This application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 63/243,292, filed Sep. 13, 2021, U.S. Provisional Application No. 63/253,973, filed Oct. 8, 2021, and U.S. Provisional Application No. 63/340,894, filed May 11, 2022, the entire contents thereof are hereby expressly incorporated by reference as though fully set forth herein.
The instant application contains a Sequence Listing which has been submitted electronically in ST.26 XML format and is hereby incorporated by reference in its entirety. Said XML document, created on Sep. 13, 2022, is named TP109206WO1_SL.XML and is 425,000 bytes in size.
The present disclosure relates to compositions including recombinant nucleases, recombinant nucleases operatively linked to nucleic acid binding domains, and methods of making and using them.
The recent advances in TALENs or CRISPR-mediated genome editing tools enable researchers to introduce double-strand breaks (DSBs) in mammalian genome efficiently. The DSBs are then mostly repaired by either the non-homologous end joining (NHEJ) pathway or the homology-directed repair (HDR) pathway. In mammalian cells, the NHEJ pathway is predominant and error-prone. However, the HDR pathway allows for precise genome editing via the use of sister chromatids or exogenous DNA molecules.
TALE (transcription activator-like effector) proteins, also referred to herein as “TAL proteins”, have a DNA binding domain (DBD) comprising an array of motifs of roughly 30-40 (e.g., 33-35) amino acid repeats that can be modified to bind to a sequence of interest. When a nuclease is fused to the TALE DBD, the resulting fusion protein (called TALEN) can efficiently target and/or process nucleic acids to affect genome editing within a cell.
Transcription activator-like (TAL) effectors represent a class of DNA binding proteins secreted by plant-pathogenic bacteria of the species, such as Xanthomonas and Ralstonia, via their type III secretion system upon infection of plant cells. Natural TAL effectors specifically have been shown to bind to plant promoter sequences thereby modulating gene expression and activating effector-specific host genes to facilitate bacterial propagation (Römer, P., et al., Plant pathogen recognition mediated by promoter activation of the pepper Bs3 resistance gene. Science 318, 645-648 (2007); Boch, J. & Bonas, U. Xanthomonas AvrBs3 family-type III effectors: discovery and function. Annu. Rev. Phytopathol. 48, 419-436 (2010); Kay, S., et al. U. A bacterial effector acts as a plant transcription factor and induces a cell size regulator. Science 318, 648-651 (2007); Kay, S. & Bonas, U. How Xanthomonas type III effectors manipulate the host plant. Curr. Opin. Microbiol. 12, 37-43 (2009).) Natural TAL effectors are generally characterized by a central repeat domain and a carboxyl-terminal nuclear localization signal sequence (NLS) and a transcriptional activation domain (AD). The central repeat domain typically consists of a variable amount of between 1.5 and 33.5 amino acid repeats that are usually 33-35 residues in length except for a generally shorter carboxyl-terminal repeat referred to as half-repeat. The repeats are mostly identical but differ in certain hypervariable residues. DNA recognition specificity of TAL effectors is mediated by hypervariable residues typically at positions 12 and 13 of each repeat—the so-called repeat variable diresidue (RVD) wherein each RVD targets a specific nucleotide in a given DNA sequence. Thus, the sequential order of repeats in a TAL protein tends to correlate with a defined linear order of nucleotides in a given DNA sequence. The underlying RVD code of some naturally occurring TAL effectors has been identified, allowing prediction of the sequential repeat order required to bind to a given DNA sequence (Boch, J. et al. Breaking the code of DNA binding specificity of TAL-type III effectors. Science 326, 1509-1512 (2009); Moscou, M. J. & Bogdanove, A. J. A simple cipher governs DNA recognition by TAL effectors. Science 326, 1501 (2009)). Further, TAL effectors generated with new repeat combinations have been shown to bind to target sequences predicted by this code. It has been shown that the target DNA sequence generally start with a 5′ thymine base to be recognized by the TAL protein.
The modular structure of TALEs allows for combination of the DNA binding domain with effector molecules such as nucleases. In particular, TAL effector nucleases allow for the development of new genome engineering tools.
There exists a substantial need for efficient systems and techniques for modifying genomes.
The instant technology generally relates to compositions and methods of uses of alternative nucleases (ANs) described herein.
In one aspect, the present disclosure provides a recombinant protein comprising a cleavage domain, wherein the cleavage domain comprises an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with the amino acid sequence of any one of SEQ ID NO: 200, 282 and 296-299, or a functional fragment thereof. In some embodiments, the recombinant protein further includes a nucleic acid binding domain operatively linked thereto. In embodiments, the nucleic acid binding domain is operatively linked to the recombinant protein via a covalent linkage. In embodiments, the nucleic acid binding domain is operatively linked to the recombinant protein via a non-covalent linkage. In embodiments, the recombinant protein is a fusion protein.
In embodiments wherein the recombinant proteins provided herein include a nucleic acid binding domain operatively linked to the cleavage domain, the nucleic acid binding domain described herein is a zinc finger nucleic acid binding domain. In other embodiments, the nucleic acid binding domain described herein is a transcription activator-like effector (TALE) deoxyribonucleic acid binding domain (DBD). In some embodiments, the TALE DBD is a T-less TALE DBD. In some embodiments, the TALE is derived from Xanthomonas, Ralstonia, or Burkholderia.
In some embodiments, the nucleic acid binding domain specifically binds to a target nucleic acid sequence in a nucleic acid molecule. In some embodiments, the target nucleic acid includes a first and a second target half site, wherein the nucleic acid binding domain specifically binds to a target half site.
In some embodiments, the cleavage domain cleaves the nucleic acid molecule at a cleavage site within the target nucleic acid sequence when a first and second nucleic acid binding domain (within a first and a second recombinant protein) bind to the first and second target half site, respectively.
In some embodiments, the nucleic acid binding domain comprises one or more repeat units. In some embodiments, each of the one or more repeat units is 30 amino acids to 45 amino acids in length, and wherein each repeat unit recognizes a nucleotide base. In some embodiments, each of the one or more repeat units is 32 amino acids to 40 amino acids in length. In some embodiments, at least one repeat unit is a non-naturally occurring repeat unit.
In some embodiments, the nucleic acid binding domain binds to a DNA target sequence. In some embodiments, the nucleic acid binding domain binds to a DNA target sequence and the cleavage domain cleaves DNA.
In another aspect, the present disclosure provides a nucleic acid encoding the recombinant protein described herein, such as an RNA (e.g., an mRNA, self-replicating RNA, o-RNA, or the like) or a DNA (e.g., a dsDNA within vector, or the like).
In another aspect, the present disclosure provides a vector comprising the nucleic acid described herein.
In another aspect, the present disclosure provides a cell comprising the recombinant protein, the nucleic acid, or the vector described herein.
In some embodiments, the cell is a prokaryotic cell. In some embodiments, the cell is a eukaryotic cell. In some embodiments, the cell is a plant cell, a yeast cell, an insect cell, or a mammalian cell.
In some embodiments, the cell further comprises a donor nucleic acid, such as a donor DNA and/or a donor RNA.
In some embodiments, the cell is genetically modified.
In another aspect, the present disclosure provides a method of modifying a genome comprising contacting a cell with the recombinant protein described herein (e.g., that includes a recombinant nuclease as provided herein operatively linked to a nucleic acid binding domain).
In another aspect, the present disclosure provides a method of genetically altering a cell, comprising contacting the cell with a recombinant protein (including a recombinant nuclease operably linked to a nucleic acid binding domain) described herein under conditions such that the recombinant protein binds a target DNA sequence in the cell (e.g., such that a first target half site and a second target half site are bound by a first DNA binding domain and a second DNA binding domain of first and second recombinant proteins provided herein, respectively). In some embodiments, the first and second target half sites are bound by a homodimer comprising two identical recombinant proteins (e.g., two identical recombinant nucleases operably liked to a nucleic acid binding domain) as described herein. In some embodiments, the first and second target half sites are bound by a heterodimer comprising different first and second recombinant proteins as described herein.
In another aspect, the present disclosure provides a method of modifying a genome comprising contacting a cell with the nucleic acid or the vector described herein.
In another aspect, the present disclosure provides a method of genetically altering a cell, comprising contacting the cell with the nucleic acid or the vector described herein under conditions such that the recombinant protein (e.g., that includes a recombinant nuclease operatively linked to a nucleic acid binding domain) is expressed and binds a target sequence in the cell.
In some embodiments, the nucleic acid or vector comprises RNA. In some embodiments, the nucleic acid or vector comprises DNA.
In another aspect, the present disclosure provides a method for modifying the genome of a cell, the method comprising: introducing into the cell a recombinant protein described herein (e.g., including a recombinant nuclease as provided herein operatively linked to a nucleic acid binding domain), or a nucleic acid encoding a recombinant protein described herein, where the recombinant protein binds to a target site within the cell’s genome (e.g., a target site comprising a first and a second target half site, wherein the nucleic acid binding domain of the recombinant protein specifically binds to a target half site sequence), and wherein binding of recombinant proteins as described herein to the target site (e.g., to the first and second target half sites) results in cleavage of the genome of the cell at a cleavage site within the target site.
In some embodiments, the method further comprises introducing into the cell a donor nucleic acid, such that at least a portion of the donor nucleic acid is inserted into the genome of the cell at a cleavage site that has been cleaved by a recombinant protein as described herein.
In some embodiments, two or more recombinant proteins (e.g., each including a recombinant nuclease operably linked to a nucleic acid binding domain) or two or more nucleic acids encoding the two or more recombinant proteins are introduced into the cell, wherein the first and second recombinant proteins form homo and/or heterodimers and/or both homo and heterodimers within the cell. In some embodiments, the introduction of the recombinant proteins or the nucleic acids encoding the recombinant proteins results in cleavage of the genome within first and second target sites.
In some embodiments, modification the genome of a cell comprises double stranded cleavage of a cleavage site within the target nucleic acid.
In some embodiments, the target site is a chromosomal locus.
In some embodiments, the genetic modification comprises a knock-in or insertion of one or more nucleotides. In some embodiments, the genetic modification comprises a knock-out or deletion of one or more nucleotides. In some embodiments, the genetic modification comprises a mutation or alternation of one or more nucleotides.
In another aspect, the present disclosure provides a non-naturally occurring nucleic acid encoding an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299. In some embodiments, the non-naturally occurring nucleic acid encodes an amino acid sequence having at least 80% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or a functional fragment thereof. In some embodiments, the non-naturally occurring nucleic acid encodes an amino acid sequence having at least 90% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or a functional fragment thereof. In some embodiments, the non-naturally occurring nucleic acid encodes an amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or a functional fragment thereof.
In another aspect, the present disclosure provides a kit comprising a first recombinant protein described herein or a first nucleic acid described herein, and at least one reagent for making or using the recombinant protein.
In some embodiments, the kit includes a vector comprising the nucleic acid described herein.
In some embodiments, the kit further includes a second recombinant protein or a second nucleic acid, as described herein. In some embodiments, the first and second recombinant proteins bind to a first and second target half site, respectively, and form a homodimer. In some embodiments, the first and second recombinant proteins bind to a first and second target half site, respectively, and form a heterodimer.
In some embodiments, the at least one additional reagent is selected from a transfection reagent, a DNA cloning reagent, primers to the first and/or second nucleic acid, a control nucleic acid, a third nucleic acid encoding a reporter, and/or a vector.
In another aspect, the present disclosure provides a method of treating a disease or disorder treatable by genetic modification, the method comprising contacting a cell with a recombinant protein described herein, or a nucleic acid encoding a recombinant proteins described herein, under conditions such that the recombinant protein is expressed and binds to and cleaves a target DNA sequence in the cell at a cleavage site, thereby genetically modifying the cell.
In some embodiments, the method further comprises introducing into the cell a donor DNA, such that at least a portion of the donor DNA is inserted into the genome of the cell at the cleavage site of the target DNA sequence in the cell.
In some embodiments, modification the genome of a cell comprises double stranded cleavage of a target site, e.g., within the cell’s genome. In some embodiments, modification of the genome of a cell comprises nicking one strand of a target site, e.g., within the cell’s genome
In some embodiments, the genetic modification comprises a knock-in. In some embodiments, the genetic modification comprises a knock-out. In some embodiments, the genetic modification comprises a mutation.
In some embodiments, the method further comprises administering the cell to a patient.
In some embodiments, the recombinant protein or nucleic acid is administered to a patient.
In some embodiments, the disease or disorder described herein is cancer, beta-thalassemia, sickle cell disease, hemophilia, blindness, Leber congenital amaurosis, human immune deficiency syndrome (HIV), cystic fibrosis, Duchenne’s muscular dystrophy, Huntington’s disease, familial hypercholesterolemia, Alzheimer’s disease, retinitis pigmentosa, retinal dystrophy, diabetes, autism spectrum disorder, hypertrophic cardiomyopathy, or Tay-Sachs disease.
In certain embodiments, the disease or disorder described herein is a blood cancer. In some embodiments, the disease or disorder described herein is a leukemia, lymphoma, myeloma, or myelodysplasia, including without limitation B-cell leukemias, B-cell acute lymphoblastic leukemia, B-cell lymphomas, B-cell non-Hodgkin’s lymphoma, follicular lymphoma, mantle cell lymphoma, T-cell lymphomas, Hodgkin’s lymphoma and multiple myeloma. In certain embodiments, the disease or disorder described herein is a solid tumor cancer such as, without limitation, lung cancer, ovarian cancer, cervical cancer, liver cancer, glioma, glioblastoma, prostate cancer, renal cancer pancreatic cancer, gastric cancer, breast cancer, colorectal cancer, melanomas or sarcomas.
In some embodiments, the recombinant protein described herein, when provided to a group of cells (e.g., immune cells, such as T cells), is capable of maintaining or increasing the amount of CD8+ cells in the group of cells. In some embodiments, the recombinant protein described herein, when treated to a group of cells (e.g., immune cells, such as T cells), is capable of maintaining or increasing the ratio of CD8+vs. CD4+ cells in the group of cells. In some embodiments, the recombinant protein described herein, when provided to a group of cells (e.g., immune cells, such as T cells), is capable of maintaining or increasing the amount of CD8+ cells in the group of cells to at least 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, or more than the amount of CD8+ cells in the group of naïve cells or cells treated with a CRISPR-based genome editing tool targeting the same locus, respectively.
In another aspect, the present disclosure provides a composition comprising a recombinant protein as described herein for treating a group of cells or a subject to maintain or increase the amount of CD8+ cells and/or the ratio of CD8+ cells vs. CD4+ cells in the group of cells or the subject.
In another aspect, the present disclosure provides a method of maintaining or increasing the amount of CD8+ cells and/or the ratio of CD8+ cells vs. CD4+ cells in a group of cells or a subject, the method comprising treating the group of cells or the subject a composition comprising a recombinant protein as described herein.
FIG. 1 is a bar graph showing gene editing efficiency of a set of alternative nucleases screened at AAVS1 in HEK293FT cells, as determined by genomic cleavage detection assay (GCD), as described in Example 1 and Example 2. 100 ng of each mRNA (encoding a first and a second recombinant protein) as described herein (200 ng per recombinant protein pair) was used and transfected into cells using the Neon electroporator. Transfections were performed in duplicate and the editing efficiency was averaged. Percent identity of each alternative nuclease to Fokl or Clo51 is displayed under the bar graph.
FIG. 2 is a bar graph showing gene editing efficiency (determined by GCD) for the top six alternative nucleases from the set of alternative nucleases depicted in FIG. 1. The alternative nucleases were tested again for repeatability in HEK293FT cells at the AAVS1 target. 100 ng of each mRNA (encoding a first and a second recombinant protein) as described herein (200 ng per recombinant protein pair) was used and transfected into cells using the Neon electroporator. Transfections were performed in duplicate and the editing efficiency was averaged. Percent identity of each alternative nuclease to Fokl or Clo51 is displayed under the graph. The alternative nucleases exhibiting the highest editing efficiencies were designated with circles at the end of the bars.
FIG. 3 is a bar graph showing gene editing efficiency (determined by GCD) for 14 alternative nucleases screened at the AAVS1 locus in HEK293FT cells as described in Examples 1 and 2. 100 ng of each mRNA (encoding a first and a second recombinant protein) as described herein (200 ng per recombinant protein pair) was used and transfected into cells using the Neon electroporator. Transfections were performed in duplicate and the editing efficiency was averaged. Percent identity of each alternative nuclease to Fokl or Clo51 is displayed under the bar graph. The alternative nucleases exhibiting the highest editing efficiencies were designated with circles at the end of the bars.
FIG. 4 is a bar graph showing gene editing efficiency (determined by GCD) for alternative nucleases screened at the AAVS1 locus in HEK293FT cells as described in Examples 1 and 2. 100 ng of each mRNA (encoding a first and a second recombinant protein) as described herein (200 ng per recombinant protein pair) was used and transfected into cells using the Neon electroporator. Transfections were performed in duplicate and the editing efficiency was averaged. Percent identity of each alternative nuclease to Fokl or Clo51 is displayed under the bar graph. The alternative nucleases exhibiting the highest editing efficiencies were designated with circles at the end of the bars.
FIG. 5 is a bar graph showing gene editing efficiency (determined by GCD) for alternative nucleases screened at the AAVS1 locus in HEK293FT cells as described in Examples 1 and 2. 100 ng of each mRNA (encoding a first and a second recombinant protein) as described herein (200 ng per recombinant protein pair) was used and transfected into cells using the Neon electroporator. Transfections were performed in duplicate and the editing efficiency was averaged. Percent identity of each alternative nuclease to Fokl or Clo51 is displayed under the bar graph. The alternative nucleases exhibiting the highest editing efficiencies were designated with circles at the end of the bars.
FIG. 6 is a bar graph showing gene editing efficiency (determined by GCD) for alternative nucleases screened at the AAVS1 locus in HEK293FT cells as described in Examples 1 and 2. 100 ng of each mRNA (encoding a first and a second recombinant protein) as described herein (200 ng per recombinant protein pair) was used and transfected into cells using the Neon electroporator. Transfections were performed in duplicate and the editing efficiency was averaged. Percent identity of each alternative nuclease to Fokl or Clo51 is displayed under the bar graph. The alternative nuclease exhibiting the highest editing efficiency was designated with a circle at the end of the bar.
FIG. 7 is a bar graph showing gene editing efficiency (determined by GCD) for the top performing alternative nucleases shown in FIGS. 3–6. The alternative nucleases were tested again for repeatability in HEK293FT cells at the AAVS1 target. 100 ng of each mRNA (encoding a first and a second recombinant protein) as described herein (200 ng per recombinant protein pair) was used and transfected into cells using the Neon electroporator. Transfections were performed in duplicate and the editing efficiency was averaged. Percent identity of each alternative nuclease to Fokl or Clo51 is displayed under the graph.
FIG. 8 is a bar graph showing gene editing efficiency (determined by GCD) for the top performing alternative nucleases showing in FIG. 7, tested at the TRAC48 locus. 100 ng of each mRNA (encoding a first and a second recombinant protein) as described herein (200 ng per recombinant protein pair) was used and transfected into cells using the Neon electroporator. Transfections were performed in duplicate and the editing efficiency was averaged. * indicates extreme toxicity shown post-transfection
FIG. 9 is a bar graph showing the gene editing efficiency (determined by GCD) at AAVS1 versus TRAC48 for each indicated alternative nuclease.
FIG. 10A is a bar graph showing gene editing efficiency of various versions of the AN197 TALEN recombinant protein, with different versions including successive amino acid additions at the N-terminus, as indicated, compared to a Fokl TALEN nuclease. The recombinant AN197 TALEN proteins were tested for gene editing efficiency (determined by GCD) at the TRAC48 and TRAC15 loci in HEK293 cells, as described in Examples 1 and 2.
FIG. 10B is a screenshot from JPRED4 of the predicted secondary structure of the N-terminus of AN197 nuclease. The original construct used in the GCD assays shown in FIG. 6, FIG. 7 and FIG. 8 assays starts at the isoleucine indicated by the arrow. The constructs showing in FIG. 10A increase the N-terminus in succession up to the alanine in position 17.
FIG. 11A shows an agarose gel depicting a genomic cleavage detection assay in primary T cells from two different donors (Donor S and Donor M). Primary T cells were electroporated with mRNA encoding an AN197 recombinant protein as described herein, an mRNA encoding Fokl TALEN, or negative control (shocked cells). The AN197 TALEN and Fokl TALEN nucleases were designed to target the human AAVS1 locus, as described in Examples 1 and 2.
FIG. 11B is a bar graph and Table showing the percent cleavage efficiency data from FIG. 11A, as determined using ALPHAMIMAGER® Software. AN197 TALEN shows similar cleavage efficiency compared to Fokl TALEN at the AAVS1 locus.
FIGS. 12A-12G are density plots depicting TCR knock-outs in activated T cells electroporated with mRNA encoding an AN197 recombinant protein operatively linked to a TALEN binding domain (FIG. 12A), mRNA encoding an AN6 recombinant protein operatively linked to a TALEN binding domain (FIG. 12B), mRNA encoding an AN159 recombinant protein operatively linked to a TALEN binding domain (FIG. 12C), mRNA encoding a Fokl TALEN (FIG. 12D) recombinant protein, or a negative control (FIG. 12E). FIG. 12F depicts a positive control (activated T cells, no stain). FIG. 12G is a bar graph showing the efficiency of TCR knock-out (% TCR knock-out) from FIGS. 12A-D.
FIG. 13 depicts panels of density plots of TCR knock out results in primary T cells from two different donors. Panels A-D are density plots depicting TCR knock out in primary T cells from two different donors (Donor A, panels A-B)(Donor B, panels C-D) electroporated with mRNA encoding a Fokl TALEN nuclease targeting the TRAC48 locus. Panels E-H are density plots depicting TCR knock out in primary T cells from two different donors (Donor A, panels E, G)(Donor B, panels F, H) electroporated with mRNA encoding AN197 operatively linked to a TALEN binding domain targeting the TRAC48 locus. Panels I-L are density plots depicting TCR knock out in primary T cells from two different donors (Donor A, panels I, K)(Donor B, panels J, L) electroporated with a CRISPR Cas9/sgRNA targeting the TRAC48 locus. Panels M-N are density plots depicting a negative control (shock only) for TCR knock out in primary T cells from two different donors (Donor A, panel M)(Donor B, panel N). Panels O-P are density plots depicting a negative control (no stain) for TCR knock out in primary T cells from two different donors (Donor A, panel 0) (Donor B, panel P). The table shows the TCR knock out efficiency data from panels A-P.
FIG. 14 depicts panels of density plots depicting TCR knock out (panels A, E, I) and CAR knock in, using increasing concentration of viral particles harboring donor DNA (10 μl: panels B, F, J) (20 μl: panels C, G, K) (30 μl: panels D, H, L)) in cells transfected with AN197 operatively linked to a TALEN binding domain (panels A-D), Fokl TALEN (panels E-H), or CRISPR (panels I-L).
FIG. 15 depicts panels of density plots depicting cells stained for markers indicative of T cell activation (CD26: panels A-D)(CD49: panels E-H), Memory T cells (CD95: panels I-L)(CD42L: panels M-P), T cell exhaustion (LAG-3: panels Q-T)(PD-1: panels U-X)(TM3: panels Y-AB); TCR (panels AC-AF); and CD4/CD8 (panels AG-AJ) in T cells transfected with AN197 operatively linked to a TALEN binding domain mRNA (panels A, E, I, M, Q, U, Y, AC, AG), Fokl TALEN mRNA (panels B, F, J, N, R, V, Z, AD, AH) or CRISPR (panels C, G, K, O, S, W, AA, AE, AI). Panels D, H, L, P, T, X, AB, AF, and AJ are naïve T cells.
FIG. 16 is a graph showing the performance of CAR-T cells (or negative control (naïve T cells)), generated using a recombinant AN197 TALEN nuclease, a Fokl TALEN, or CRISPR. Cytotoxicity of CAR-T cells was measured by the in vitro eradication of CD19-positive NALM6 cells. A flow cytometry-based assay to quantify the number of viable, CD19+ cells. NALM6 (CD19+) cells were almost completely eliminated after 4 hr of co-culture at effector (E): target (T) ratios 10:1 and 5:1. Percentage of killed cells relative to naïve T cells are shown in the graph (mean of 3 experiments ±SEM).
FIGS. 17A-17F depict TALEN AN197 editing efficiency at different targets in primary T cells. FIGS. 17A-17D and 17F shows agarose gels depicting a GCD assay at targets TIM3 (FIG. 17A), B2M (FIG. 17B), LAG3 (FIG. 17C), PD-1 (FIG. 17D) and AAVS1 (FIG. 17F). FIG. 17E is a bar graph showing the editing efficiency from FIGS. 17A-D and 17F. All targets showed higher than 80% editing efficiency detected by GCD.
FIGS. 18A-18D are graphs depicting GCD editing efficiency results of TALEN AN197 target screening for B2M (FIG. 18A), TIM3 (FIG. 18B), LAG3 (FIG. 18C) and C2TA (FIG. 18D) in HEK 293 cells.
FIGS. 19A-19C are graphs depicting the results of TALEN AN197 target screening in primary T cells for TIM3 (FIG. 19B) and LAG3 (FIG. 19C) with GCD and B2M knock out (FIG. 19A).
FIG. 20 depicts panels of density plots depicting single TRAC knock out (panel A) or single B2M knock out (panel B) or double TRAC+B2M knock out (panels D-F) with TALEN AN197 at the same time. Panel C depicts a density plot depicting a knock out negative control.
FIGS. 21A-21D are density plots depicting TALEN AN197 CAR knock-in with non-viral double-stranded DNA donor in T cells from two different donors (Donor A, FIG. 21A; Donor B, FIG. 21C) and density plots for the non-edited T cells (Donor A, FIG. 21B; Donor B, FIG. 21D).
FIGS. 22A-22D depicts editing results in primary human NK cells with TALEN AN197 and CRISPR/Cas9. The graph of FIG. 22A and agarose gel of FIG. 22B depict GCD assay results for varying amounts of TALEN AN197 mRNA. The graph of FIG. 22C and agarose gel of FIG. 22D depict GCD assay results for varying amounts of CRISPR/Cas9 RNP payload.
FIG. 23 depicts panels of density plots depicting AN197 CAR knock-in in expanded primary NK cells with AAV delivery. AN197 mRNA targeting AAVS1 was transfected into NK cells followed by the addition of AAV6-CAR at different MOI. An MOI of 7500 was used with the cells in the top row of plots (panels A-D) and an MOI of 30,000 AAV was used with the cells in the bottom row of plots (panels E-H).
FIGS. 24A-24D depicts exemplary results from iPSC’s transfected with TALEN AN197 mRNA targeting either AAVS1 or TRAC. The agarose gel of FIG. 24A and graph of
FIG. 24B depict GCD assay results in iPSCs for AAVS1 and TRAC targeted AN197 TALEN mRNA. FIG. 24C and FIG. 24D show graphs depicting relative iPSC cell number 24 hour and 96 hours after editing, respectively.
FIGS. 25A-25B depict exemplary results of TALEN AN197 protein purification (FIG. 25B) and in vitro functional activity (FIG. 25A).
FIGS. 26A-26B depicts exemplary multiplex target editing in HEK 293 cells with 1, 2, 3, or 4 TALEN AN197 pairs targeting the indicated targets. FIG. 26A is a graph depicting the editing efficiencies at AAVS1 and FIG. 26B is a graph depicting the editing efficiencies at B 2M1.
FIGS. 27A-27B depicts exemplary multiplex target editing in HEK 293 cells with 1, 2, 3, or 4 TALEN AN197 pairs targeting the indicated targets. FIG. 27A is a graph depicting the editing efficiencies at TRAC48 and FIG. 27B is a graph depicting the editing efficiencies at C2TA.
After reading this description it will become apparent to one skilled in the art how to implement the present disclosure in various alternative embodiments and alternative applications. However, all the various embodiments of the present invention will not be described herein. It will be understood that the embodiments presented here are presented by way of an example only, and not limitation. As such, this detailed description of various alternative embodiments should not be construed to limit the scope or breadth of the present disclosure as set forth herein.
Before the present technology is disclosed and described, it is to be understood that the aspects described below are not limited to specific compositions, methods of preparing such compositions, or uses thereof as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.
The detailed description divided into various sections only for the reader’s convenience and disclosure found in any section may be combined with that in another section. Titles or subtitles may be used in the specification for the convenience of a reader, which are not intended to influence the scope of the present disclosure.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In this specification and in the claims that follow, reference will be made to a number of terms that shall be defined to have the following meanings:
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
“Optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.
The term “about” when used before a numerical designation, e.g., temperature, time, amount, concentration, and such other, including a range, indicates approximations which may vary by (+) or (−) 10%, 5%, 1%, or any subrange or subvalue there between. Preferably, the term “about” when used with regard to an amount means that the amount may vary by +/−10%.
“Comprising” or “comprises” is intended to mean that the compositions and methods include the recited elements, but not excluding others. “Consisting essentially of” when used to define compositions and methods, shall mean excluding other elements of any essential significance to the combination for the stated purpose. Thus, a composition consisting essentially of the elements as defined herein would not exclude other materials or steps that do not materially affect the basic and novel characteristic(s) of the claimed invention.” Consisting of shall mean excluding more than trace elements of other ingredients and substantial method steps. Embodiments defined by each of these transition terms are within the scope of this disclosure.
As used herein “TAL effector” or “TAL effector protein” as provided herein refers to a protein including more than one TAL repeat and capable of binding to nucleic acid in a sequence specific manner. In embodiments, TAL effector protein includes at least six (e.g., at least 8, at least 10, at least 12, at least 15, at least 17, from about 6 to about 25, from about 6 to about 35, from about 8 to about 25, from about 10 to about 25, from about 12 to about 25, from about 8 to about 22, from about 10 to about 22, from about 12 to about 22, from about 6 to about 20, from about 8 to about 20, from about 10 to about 22, from about 12 to about 20, from about 6 to about 18, from about 10 to about 18, from about 12 to about 18, etc.) TAL repeats. In embodiments, the TAL effector protein includes 18 or 24 or 17.5 or 23.5 TAL nucleic acid binding cassettes. In embodiments, the TAL effector protein includes 15.5, 16.5, 17.5, 18.5, 19.5, 20.5, 21.5, 22.5 or 24.5 TAL nucleic acid binding cassettes. A TAL effector protein includes at least one polypeptide region which flanks the region containing the TAL repeats. In embodiments, flanking regions are present at the amino and/or the carboxyl termini of the TAL repeats. As used herein, the term “TALEN” refers to a TAL effector protein associated with a nuclease domain.
As used herein, the term “operatively linked” is used in connection with two or more components, in which the components linked such that both components function normally and allow the possibility that at least one of the components can mediate a function that is exerted upon at least one of the other components. By way of illustration, a polypeptide comprising a nucleic acid binding domain a DNA binding domain) and a cleavage domain are “operatively linked” When the domains retain their nucleic acid and binding functions, respectively, e.g., upon covalent or non-covalent linkage to each other.
As used herein the term “homologous recombination” or “homology-directed repair” (or “HDR”) refers to a mechanism of genetic recombination in which two DNA strands comprising similar nucleotide sequences exchange genetic material. Cells use homologous recombination during meiosis, where it serves to rearrange DNA to create an entirely unique set of haploid chromosomes, but also for the repair of damaged DNA, in particular for the repair of double strand breaks. The mechanism of homologous recombination is well known to the skilled person and has been described, for example by Paques and Haber (Paques F, Haber J E.; Microbial. Mal. Biol. Rev. 63:349-404 (1999)). In aspects, homologous recombination is enabled by the presence of said first and said second flanking element being placed upstream (5′) and downstream (3′), respectively, of said donor DNA sequence each of which being homologous to a continuous DNA sequence within said target sequence. As used herein the term “HDR-mediated genome editing” refers to genome editing that occurs through a HDR mechanism.
A “functional fragment” of a protein, polypeptide or nucleic acid is a protein, polypeptide or nucleic acid whose sequence is not identical to the full-length protein, polypeptide or nucleic acid, yet retains the same function as the full-length protein, polypeptide or nucleic acid. A functional fragment can possess more, fewer, or the same number of residues as the corresponding native molecule, and/or can contain one or more amino acid or nucleotide substitutions. Methods for determining the function of a nucleic acid (e.g., coding function, ability to hybridize to another nucleic acid) are well-known in the art. Similarly, methods for determining protein function are well-known. For example, the DNA-binding function of a polypeptide can be determined, for example, by filter-binding, electrophoretic mobility-shift, or immunoprecipitation assays. DNA cleavage can be assayed by gel electrophoresis, See Ausubel et al., supra. The ability of a protein to interact with another protein can be determined, for example, by co. immunoprecipitation, two-hybrid assays or complementation, both genetic and biochemical. See, for example, Fields et al. (1989) Nature 340:245-246; U.S. Pat. No. 5,585,245 and PCT WO 98/44350.
As used herein, “transcription activator-like effectors” (TALEs) refer to proteins composed of more than one TAL repeat and is capable of binding to nucleic acid in a sequence specific manner. TALEs represent a class of DNA binding proteins secreted by plant-pathogenic bacteria of the species, such as Xanthomonas and Ralstonia, via their type III secretion system upon infection of plant cells. Natural TALEs specifically have been shown to bind to plant promoter sequences thereby modulating gene expression and activating effector-specific host genes to facilitate bacterial propagation (Römer, P., et al., Science 318:645-648 (2007); Boch, J., et al., Annu. Rev. Phytopathol. 48:419-436 (2010); Kay, S., et al., Science 3/8:648-651 (2007); Kay, S., et al., Curr. Opin. Microbiol. 12:37-43 (2009)).
Natural TALEs are generally characterized by a central repeat domain and a carboxyl-terminal nuclear localization signal sequence (NLS) and a transcriptional activation domain (AD). The central repeat domain typically consists of a variable amount of between 1.5 and 33.5 amino acid repeats that are usually 33-35 residues in length except for a generally shorter carboxyl-terminal repeat referred to as half-repeat. The repeats are mostly identical but differ in certain hypervariable residues. DNA recognition specificity of TALEs is mediated by hypervariable residues typically at positions 12 and 13 of each repeat—the so-called repeat variable diresidue (RVD) wherein each RVD targets a specific nucleotide in a given DNA sequence. Thus, the sequential order of repeats in a TAL protein tends to correlate with a defined linear order of nucleotides in a given DNA sequence. The underlying RVD code of some naturally occurring TALEs has been identified, allowing prediction of the sequential repeat order required to bind to a given DNA sequence (Boch, J., et al., Science 326:1509-1512 (2009); Moscou, M. J., et al., Science 326:1501 (2009)). Further, TAL effectors generated with new repeat combinations have been shown to bind to target sequences predicted by this code. It has been shown that the target DNA sequence generally start with a 5′ thymine base to be recognized by the TAL protein.
The modular structure of TALEs and ZFN’s allows for combination of the DNA binding domain with effector molecules such as nucleases. For example, TALE nucleases allow for the development of new genome engineering tools.
TALEs used in some embodiments may generate DS breaks or may have a combined action for the generation of DS breaks. For example, TAL-Fokl nuclease fusions can be designed to bind at or near a target locus and form double-stranded nucleic acid cutting activity by the association of two Fokl domains.
In some embodiments, TALEs will contain greater than or equal to 6 (e.g., greater than or equal to 8, 10, 12, 15, or 17, or from 6 to 25, 6 to 35, 8 to 25, 10 to 25, 12 to 25, 8 to 22, 10 to 22, 12 to 22, 6 to 20, 8 to 20, 10 to 22, 12 to 20, 6 to 18, 10 to 18, 12 to 18, etc.) TAL repeats. In some embodiments, a TALE may contain 18 or 24 or 17.5 or 23.5 TAL nucleic acid binding cassettes. In additional embodiments, a TALE may contain 15.5, 16.5, 17.5, 18.5, 19.5, 20.5, 21.5, 22.5 or 24.5 TAL nucleic acid binding cassettes. TALEs will generally have at least one polypeptide region which flanks the region containing the TALE repeats. In many embodiments, flanking regions will be present at both the amino and carboxyl termini of the TAL repeats. Exemplary TALEs are set out in U.S. Pat. Publ. No. 2013/0274129 A1, the disclosure of which is incorporated herein by reference, and may be modified forms on naturally occurring proteins found in bacteria of the genera Burkholderia, Xanthamonas and Ralstonia.
In some embodiments, the recombinant proteins provided herein will contain nuclear localization signals (NLS) that allow them to be transported to the nucleus. For example, in some embodiments, the recombinant proteins include 1, 2, 3, 4, or more NLS’s. In some embodiments, the recombinant proteins include one or more NLS’s at the amino-terminus of the protein. In some embodiments, the recombinant proteins include one or more NLS’s at the carboxy-terminus of the protein. In some embodiments, the recombinant proteins include one or more NLS’s at the amino terminus of the protein, and one or more NLS’s at the carboxy terminus of the protein. In some embodiments, the recombinant proteins include an NLS that is internal (i.e., not at the amino or carboxy-terminus) of the protein. Preferably, the recombinant fusion proteins provided herein include an NLS between a nucleic acid binding domain and cleavage domain, and a NLS at the carboxy-terminus of the cleavage domain. In some embodiments, the recombinant fusion proteins provided herein include an NLS between a nucleic acid binding domain and cleavage domain, an NLS at the amino-terminus of the recombinant protein (e.g., at the amino terminus of the nucleic acid binding domain) and an NLS at the carboxy-terminus of the recombinant protein (e.g., at the carboxy terminus of the cleavage domain).
In some embodiments, the recombinant proteins provided herein are operatively linked to a TALE DBD. The TALE DBD can include one or more non-canonical RVDs. Non-canonical RVD’s useful in the recombinant proteins provided herein include, but are not limited to, those described in U.S. Pat. No. 8,586,526 and, U.S. Pat. No. 9,522,938. U.S. Patent Publication 20130196373, and the like.
The terms “polypeptide,” “peptide” and “protein” are used interchangeably herein to refer to a polymer of amino acid residues, wherein the polymer may in embodiments be conjugated to a moiety that does not consist of amino acids. The terms apply to amino acid polymers in which one or more amino acid residue is an artificial chemical mimetic of a corresponding naturally occurring amino acid, as well as to naturally occurring amino acid polymers and non-naturally occurring amino acid polymers.
As may be used herein, the terms “nucleic acid,” “nucleic acid molecule,” “nucleic acid oligomer,” “oligonucleotide,” “nucleic acid sequence,” “nucleic acid fragment” and “polynucleotide” are used interchangeably and are intended to include, but are not limited to, a polymeric form of nucleotides covalently linked together that may have various lengths, either deoxyribonucleotides or ribonucleotides, or analogs, derivatives or modifications thereof. Different polynucleotides may have different three-dimensional structures, and may perform various functions, known or unknown. Non-limiting examples of polynucleotides include a gene, a gene fragment, an exon, an intron, intergenic DNA (including, without limitation, heterochromatic DNA), messenger RNA (mRNA), transfer RNA, ribosomal RNA, a ribozyme, cDNA, a recombinant polynucleotide, a branched polynucleotide, a plasmid, a vector, isolated DNA of a sequence, isolated RNA of a sequence, a nucleic acid probe, and a primer. Polynucleotides useful in the methods of the disclosure may comprise natural nucleic acid sequences and variants thereof, artificial nucleic acid sequences, or a combination of such sequences.
A polynucleotide is typically composed of a specific sequence of four nucleotide bases: adenine (A); cytosine (C); guanine (G); and thymine (T) (uracil (U) for thymine (T) when the polynucleotide is RNA). Thus, the term “polynucleotide sequence” is the alphabetical representation of a polynucleotide molecule; alternatively, the term may be applied to the polynucleotide molecule itself. This alphabetical representation can be input into databases in a computer having a central processing unit and used for bioinformatics applications such as functional genomics and homology searching. Polynucleotides may optionally include one or more non-standard nucleotide(s), nucleotide analog(s) and/or modified nucleotides.
“Conservatively modified variants” applies to both amino acid and nucleic acid sequences. With respect to particular nucleic acid sequences, “conservatively modified variants” refers to those nucleic acids that encode identical or essentially identical amino acid sequences. Because of the degeneracy of the genetic code, a number of nucleic acid sequences will encode any given protein. For instance, the codons GCA, GCC, GCG and GCU all encode the amino acid alanine. Thus, at every position where an alanine is specified by a codon, the codon can be altered to any of the corresponding codons described without altering the encoded polypeptide. Such nucleic acid variations are “silent variations,” which are one species of conservatively modified variations. Every nucleic acid sequence herein which encodes a polypeptide also describes every possible silent variation of the nucleic acid. One of skill will recognize that each codon in a nucleic acid (except AUG, which is ordinarily the only codon for methionine, and TGG, which is ordinarily the only codon for tryptophan) can be modified to yield a functionally identical molecule. Accordingly, each silent variation of a nucleic acid which encodes a polypeptide is implicit in each described sequence.
As to amino acid sequences, one of skill will recognize that individual substitutions, deletions or additions to a nucleic acid, peptide, polypeptide, or protein sequence which alters, adds or deletes a single amino acid or a small percentage of amino acids in the encoded sequence is a “conservatively modified variant” where the alteration results in the substitution of an amino acid with a chemically similar amino acid. Conservative substitution tables providing functionally similar amino acids are well known in the art. Such conservatively modified variants are in addition to and do not exclude polymorphic variants, interspecies homologs, and alleles of the disclosure.
The following eight groups each contain amino acids that are conservative substitutions for one another: 1) Alanine (A), Glycine (G); 2) Aspartic acid (D), Glutamic acid (E); 3) Asparagine (N), Glutamine (Q); 4) Arginine (R), Lysine (K); 5) Isoleucine (I), Leucine (L), Methionine (M), Valine (V); 6) Phenylalanine (F), Tyrosine (Y), Tryptophan (W); 7) Serine (S), Threonine (T); and 8) Cysteine (C), Methionine (M) (see, e.g., Creighton, Proteins (1984)).
“Percentage of sequence identity” is determined by comparing two optimally aligned sequences over a comparison window, wherein the portion of the polynucleotide or polypeptide sequence in the comparison window may comprise additions or deletions (i.e., gaps) as compared to the reference sequence (which does not comprise additions or deletions) for optimal alignment of the two sequences. The percentage is calculated by determining the number of positions at which the identical nucleic acid base or amino acid residue occurs in both sequences to yield the number of matched positions, dividing the number of matched positions by the total number of positions in the window of comparison and multiplying the result by 100 to yield the percentage of sequence identity.
The terms “identical” or percent “identity,” in the context of two or more nucleic acids or polypeptide sequences, refer to two or more sequences or subsequences that are the same or have a specified percentage of amino acid residues or nucleotides that are the same (i.e., about 60% identity, preferably 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or higher identity over a specified region, when compared and aligned for maximum correspondence over a comparison window or designated region) as measured using a BLAST or BLAST 2.0 sequence comparison algorithms with default parameters described below, or by manual alignment and visual inspection (see, e.g., NCBI web site www.ncbi.nlm.nih.gov/BLAST/or the like). Such sequences are then said to be “substantially identical.” This definition also refers to, or may be applied to, the compliment of a test sequence. The definition also includes sequences that have deletions and/or additions, as well as those that have substitutions. As described below, the preferred algorithms can account for gaps and the like. Preferably, identity exists over a region that is at least about 25 amino acids or nucleotides in length, or more preferably over a region that is 50-100 amino acids or nucleotides in length.
The term “functional fragment” in reference to a protein, polypeptide, or nucleic acid means a protein polypeptide or nucleic acid whose sequence is not identical to the full-length protein, polypeptide or nucleic acid, yet retains (at least partially), the same function as the full-length protein, polypeptide or nucleic acid. Function can be determined by well known methods. For example, nuclease activity can be determined by a genomic cleavage detection assay as described herein. The nucleic acid binding function of a polypeptide can be determined by art-accepted methods such as mobility shift assays, immunoprecipitation assays, or the like.
The term “expression” of a polypeptide includes any step involved in the production of the polypeptide including, but not limited to, transcription, post-transcriptional modification, translation, post-translational modification, and secretion. Expression can be detected using conventional techniques for detecting protein (e.g., ELISA, Western blotting, flow cytometry, immunofluorescence, immunohistochemistry, etc.).
A “vector” as used herein is a nucleic acid molecule that can be used as a vehicle to transfer genetic material into a cell. A vector can be a plasmid, a virus or bacteriophage, a cosmid or an artificial chromosome such as, e.g., yeast artificial chromosomes (YACs), bacterial artificial chromosomes (BAC) or other sequences which are able to replicate or be replicated in vitro or in a host cell, or to convey a desired nucleic acid segment to a desired location within a host cell. In embodiments a vector refers to a DNA molecule harboring at least one origin of replication, a multiple cloning site (MCS) and one or more selection markers. A vector is typically composed of a backbone region and at least one insert or transgene region or a region designed for insertion of a DNA fragment or transgene such as an MCS. The backbone region often contains an origin of replication for propagation in at least one host and one or more selection markers. A vector can have one or more restriction endonuclease recognition sites (e.g., two, three, four, five, seven, ten, etc.) at which the sequences can be cut in a determinable fashion without loss of an essential biological function of the vector, and into which a nucleic acid fragment can be spliced in order to bring about its replication and cloning. Vectors can further provide primer sites (e.g., for PCR), transcriptional and/or translational initiation and/or regulation sites, recombinational signals, replicons, selectable markers, etc. Clearly, methods of inserting a desired nucleic acid fragment which do not require the use of recombination, transpositions or restriction enzymes (such as, but not limited to, uracil N glycosylase (UDG) cloning of PCR fragments (U.S. Pat. Nos. 5,334,575 and 5,888,795, both of which are entirely incorporated herein by reference), T:A cloning, and the like) can also be applied to clone a fragment into a cloning vector to be used according to the present technology. In embodiments, a vector contains additional features. Such additional features may include natural or synthetic promoters, genetic markers, antibiotic resistance cassettes or selection markers (e.g., toxins such as ccdB or tse2), epitopes or tags for detection, manipulation or purification (e.g., V5 epitope, c-myc, hemagglutinin (HA), FLAG™ polyhistidine (His), glutathione-S-transferase (GST), maltose binding protein (MBP)), scaffold attachment regions (SARs) or reporter genes (e.g., green fluorescent protein (GFP), red fluorescence protein (RFP), luciferase, β-galactosidase etc.). In embodiments, vectors are used to isolate, multiply or express inserted DNA fragments in a target host. A vector can for example be a cloning vector, an expression vector, a functional vector, a capture vector, a co-expression vector (for expression of more than one open reading frame), a viral vector or an episome (i.e., a nucleic acid capable of extrachromosomal replication) etc.
A “cloning vector” as used herein includes any vector that can be used to delete, insert, replace or assemble one or more nucleic acid molecules. In embodiments a cloning vector may contain a counter selectable marker gene (such as, e.g., ccdB or tse2) that can be removed or replaced by another transgene or DNA fragment. In embodiments a cloning vector may be referred to as donor vector, entry vector, shuttle vector, destination vector, target vector, functional vector or capture vector. Cloning vectors typically contain a series of unique restriction enzyme cleavage sites (e.g., type II or type IIS) for removal, insertion or replacement of DNA fragments. Alternatively, DNA fragments can be replaced or inserted by TOPO® Cloning or recombination as, e.g., employed in the GATEWAY® Cloning System offered by Invitrogen/Life Technologies (Carlsbad, Calif.). A cloning vector that can be used for expression of a transgene in a target host may also be referred to as expression vector. In embodiments a cloning vector is engineered to obtain the modular polypeptides as described herein.
An “expression vector” is designed for expression of a transgene and generally harbors at least one promoter sequence that drives expression of the transgene. Expression as used herein refers to transcription of a transgene or transcription and translation of an open reading frame and can occur in a cell-free environment such as a cell-free expression system or in a host cell. In embodiments expression of an open reading frame or a gene results in the production of a polypeptide or protein. An expression vector is typically designed to contain one or more regulatory sequences such as enhancer, promoter and terminator regions that control expression of the inserted transgene. Suitable expression vectors include, without limitation, plasmids and viral vectors. Vectors and expression systems for various applications are available from commercial suppliers such as Novagen (Madison, Wis.), Clontech (Palo Alto, Calif.), Stratagene (La Jolla, Calif.), and Life Technologies Corp. (Carlsbad, Calif.). In embodiments an expression vector is engineered for expression of one or more modular proteins as described herein.
A “viral vector” generally relates to a genetically-engineered noninfectious virus containing modified viral nucleic acid sequences. In embodiments, a viral vector contains at least one viral promoter and is designed for insertion of one or more transgenes or DNA fragments. In embodiments a viral vector is delivered to a target host together with a helper virus providing packaging or other functions. In embodiments viral vectors are used to stably integrate transgenes into the genome of a host cell. A viral vector may be used for delivery and/or expression of transgenes.
Viral vectors may be derived from bacteriophage, baculoviruses, tobacco mosaic virus, vaccinia virus, retrovirus (avian leukosis-sarcoma, mammalian C-type, B-type viruses, D type viruses, HTLV-BLV group, lentivirus, spumavirus), adenovirus, parvovirus (e.g., adenoassociated viruses), coronavirus, negative strand RNA viruses such as orthomyxovirus (e.g., influenza virus) or sendai virus, rhabdovirus (e.g., rabies and vesicular stomatitis virus), paramyxovirus (e.g., measles and Sendai), positive strand RNA viruses such as picornavirus and alphavirus (such as Semliki Forest virus), and double-stranded DNA viruses including adenovirus, herpes virus (e.g., Herpes Simplex virus types 1 and 2, Epstein-Barr virus, cytomegalovirus), and poxvirus (e.g., vaccinia, fowlpox and canarypox). Other viruses include without limitation Norwalk virus, togavirus, flavivirus, reoviruses, papovavirus, hepadnavirus, and hepatitis virus. For example common viral vectors used for gene delivery are lentiviral vectors based on their relatively large packaging capacity, reduced immunogenicity and their ability to stably transduce with high efficiency a large range of different cell types. Such lentiviral vectors can be “integrative” (i.e., able to integrate into the genome of a target cell) or “non-integrative” (i.e., not integrated into a target cell genome). Expression vectors containing regulatory elements from eukaryotic viruses are often used in eukaryotic expression vectors, e.g., SV40 vectors, papilloma virus vectors, and vectors derived from Epstein-Barr virus. Other exemplary eukaryotic vectors include pMSG, pAV009/A+, pMTO10/A+, pMAMneo-5, baculovirus pDSVE, and any other vector allowing expression of proteins under the direction of the SV40 early promoter, SV40 late promoter, metallothionein promoter, murine mammary tumor virus promoter, Rous sarcoma virus promoter, polyhedrin promoter, or other promoters shown effective for expression in eukaryotic cells.
A “promoter” as used herein is a transcription regulatory sequence which is capable of directing transcription of a nucleic acid segment (e.g., a transgene comprising, for example, an open reading frame) when operably connected thereto. A promoter is a nucleotide sequence which is positioned upstream of the transcription start site (generally near the initiation site for RNA polymerase II). A promoter typically comprises at least a core, or basal motif, and may include or cooperate with at least one or more control elements such as upstream elements (e.g., upstream activation regions (UARs)) or other regulatory sequences or synthetic elements. A basal motif constitutes the minimal sequence necessary for assembly of a transcription complex required for transcription initiation. In embodiments, such minimal sequence includes a “TATA box” element that may be located between about 15 and about 35 nucleotides upstream from the site of transcription initiation. Basal promoters also may include a “CCAAT box” element (typically the sequence CCAAT) and/or a GGGCG sequence, which can be located between about 40 and about 200 nucleotides, typically about 60 to about 120 nucleotides, upstream from the transcription start site. The transcription of an adjacent nucleic acid segment is initiated at the promoter region. A repressible promoter’s rate of transcription decreases in response to a repressing agent. An inducible promoter’s rate of transcription increases in response to an inducing agent. A constitutive promoter’s rate of transcription is not specifically regulated, though it can vary under the influence of general metabolic conditions.
The choice of a promoter to be included in an expression vector depends upon several factors, including without limitation efficiency, selectability, inducibility, desired expression level, and cell or tissue specificity. For example, tissue-, organ- and cell-specific promoters that confer transcription only or predominantly in a particular tissue, organ, and cell type, respectively, can be used. In embodiments, promoters that are essentially specific to seeds (“seed-preferential promoters”) can be useful. In embodiments, constitutive promoters are used that can promote transcription in most or all tissues of a specific species. Other classes of promoters include, but are not limited to, inducible promoters, such as promoters that confer transcription in response to external stimuli such as chemical agents, developmental stimuli, or environmental stimuli. Inducible promoters may be induced by pathogens or stress like cold, heat, UV light, or high ionic concentrations or may be induced by chemicals. Examples of inducible promoters are the eukaryotic metallothionein promoter, which is induced by increased levels of heavy metals; the prokaryotic lacL promoter, which is induced in response to isopropyl-β-D-thiogalacto-pyranoside (IPTG); and eukaryotic heat shock promoters, which are induced by raised temperature. Numerous additional bacterial and eukaryotic promoters suitable for use with the technology described herein are known in the art and described in, e.g., in Sambrook et al., Molecular Cloning, A Laboratory Manual (2nd ed. 1989; 3rd ed., 2001); Kriegler, Gene Transfer and Expression: A Laboratory Manual (1990); and Ausubel et al., Current Protocols in Molecular Biology. Bacterial expression systems for expressing the ZFP are available in, e.g., E. coli, Bacillus sp., and Salmonella (Palva et al., Secretion of interferon by Bacillus subtilis. Gene 22:229-235 (1983)). Kits for such expression systems are commercially available. Eukaryotic expression systems for mammalian cells, yeast, and insect cells are well known by those of skill in the art and are also commercially available.
It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes.
In one aspect, the present disclosure provides a recombinant nuclease comprising a nucleic acid binding domain and a cleavage domain, wherein the cleavage domain comprises an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 80% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 90% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 95% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 96% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 97% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 98% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 99% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence of any one of SEQ ID NOs: 3 to 259, 282, and 296-299, or a functional fragment thereof.
In some embodiments, the cleavage domain comprises an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 200, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 80% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 200, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 90% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 200, 282 and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 95% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 200, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 96% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 200, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 97% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 200, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 98% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 200, 282, and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 99% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 200, 282 and 296-299, or a functional fragment thereof. In some embodiments, the cleavage domain comprises an amino acid sequence of any one of SEQ ID NOs: 200, 282, and 296-299, or a functional fragment thereof.
In some embodiments, the cleavage domain comprises an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with the amino acid sequence of any one of AN18 (SEQ ID NO: 19), AN21 (SEQ ID NO: 22), AN26 (SEQ ID NO: 27), AN32 (SEQ ID NO: 33), AN33 (SEQ ID NO: 34), AN35 (SEQ ID NO: 36), and AN46 (SEQ ID NO: 47), or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 80% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 19, 22, 27, 33, 34, 36, and 47 (AN18, 21, 26, 32, 33, 35, and 46, respectively), or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 90% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 19, 22, 27, 33, 34, 36, and 47 (AN18, 21, 26, 32, 33, 35, and 46, respectively), or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 95% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 19, 22, 27, 33, 34, 36, and 47 (AN18, 21, 26, 32, 33, 35, and 46, respectively), or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence of any one of SEQ ID NOs: 19, 22, 27, 33, 34, 36, and 47 (AN18, 21, 26, 32, 33, 35, and 46, respectively), or functional fragments thereof.
In some embodiments, the cleavage domain comprises an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with the amino acid sequence of any one of AN6 (SEQ ID NO: 7), AN67 (SEQ ID NO: 70), AN70 (SEQ ID NO: 73), AN77 (SEQ ID NO: 80), AN90 (SEQ ID NO: 93), AN111 (SEQ ID NO: 114), AN131 (SEQ ID NO: 134), AN140 (SEQ ID NO: 143), AN159 (SEQ ID NO: 162), AN162 (SEQ ID NO:165), and AN197 (SEQ ID NO:200), or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 80% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 7, 70, 73, 80, 93, 114, 134, 143, 162, 165, and 200 (AN6, 67, 70, 77, 90, 111, 131, 140, 159, 162, and 197, respectively), or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 90% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 7, 70, 73, 80, 93, 114, 134, 143, 162, 165, and 200 (AN6, 67, 70, 77, 90, 111, 131, 140, 159, 162, and 197, respectively), or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 95% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 7, 70, 73, 80, 93, 114, 134, 143, 162, 165, and 200 (AN6, 67, 70, 77, 90, 111, 131, 140, 159, 162, and 197, respectively), or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence of any one of SEQ ID NOs: 7, 70, 73, 80, 93, 114, 134, 143, 162, 165, and 200 (AN6, 67, 70, 77, 90, 111, 131, 140, 159, 162, and 197, respectively), or functional fragments thereof.
In some embodiments, the cleavage domain comprises an amino acid sequence having at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity with the amino acid sequence of any one of AN3 (SEQ ID NO: 4), AN12 (SEQ ID NO: 13), AN30 (SEQ ID NO: 31), AN36 (SEQ ID NO: 37), AN45 (SEQ ID NO: 46), AN65 (SEQ ID NO: 68), AN68 (SEQ ID NO: 71), AN80 (SEQ ID NO: 83), AN106 (SEQ ID NO: 109), AN108 (SEQ ID NO: 111) and AN155 (SEQ ID NO:158), or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 80% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 4, 13, 31, 37, 46, 68, 71, 83, 109, 111, and 158 (AN3, 12, 30, 36, 45, 65, 68, 80, 106, 108, and 155, respectively), or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 90% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 4, 13, 31, 37, 46, 68, 71, 83, 109, 111, and 158 (AN3, 12, 30, 36, 45, 65, 68, 80, 106, 108, and 155, respectively), or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence having at least 95% sequence identity with the amino acid sequence of any one of SEQ ID NOs: 4, 13, 31, 37, 46, 68, 71, 83, 109, 111, and 158 (AN3, 12, 30, 36, 45, 65, 68, 80, 106, 108, and 155, respectively), or functional fragments thereof. In some embodiments, the cleavage domain comprises an amino acid sequence of any one of SEQ ID NOs: 4, 13, 31, 37, 46, 68, 71, 83, 109, 111, and 158 (AN3, 12, 30, 36, 45, 65, 68, 80, 106, 108, and 155, respectively), or functional fragments thereof.
The recombinant nuclease described herein can be operatively linked (e.g., covalently or non-covalently linked) to a nucleic acid binding domain. In some embodiments, the recombinant nucleases are fusion proteins, that include a cleavage domain as described herein, and a DNA binding domain. In some embodiments, fusion proteins provided herein include a linker, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more, amino acids, between the nuclease domain and the nucleic acid binding domain.
In some embodiments, the recombinant nucleases provided herein include a nucleic acid binding domain operatively linked to the N-terminus of nuclease domain. In some embodiments, the recombinant nucleases provided herein include a nucleic acid binding domain operatively linked to the C-terminus of the nuclease domain.
In addition to fusion proteins, which provide a covalent linkage of two domains (e.g., a recombinant nuclease provided herein and a nucleic acid binding domain) via peptide bonds between amino acids, other means for covalently linking, e.g., a nucleic acid binding domain to the amino- or carboxy-terminus of a nuclease provided herein include, but are not limited to “click chemistry” (see, e.g., U.S. Pat. Nos. 7,375,234 and 7,070,941, and US Patent Publication No. 2013/0046084, the entire disclosures of which are incorporated herein by reference). A number of click reactions can be used to link polypeptide segments (e.g., Cu-azide-alkyne, strain-promoted-azide-alkyne, staudinger ligation, tetrazine ligation, photo-induced tetrazole-alkene, thiol-ene, NHS esters, epoxides, isocyanates, and aldehyde—aminooxy). Ligation of polypeptide molecules using a click chemistry reaction is advantageous because click chemistry reactions are fast, modular, efficient, often do not produce toxic waste products, can be done with water as a solvent, and can be set up to be stereospecific.
Other means to operatively link the recombinant nucleases provided herein to nucleic acid binding domains include the use of polyethylene glycol cross-linkers. Further, cross-linkers may be cleavable or non-cleavable.
One category of cross-linker that may be used to connect recombinant nucleases provided herein to a nucleic acid binding domain is amine-to-sulfhydryl heterobifunctional protein cross-linkers. These may be used to conjugate two polypeptides between primary amine (lysine) and sulfhydryl (cysteine) groups. Further, cross-linkers of this type are available with different lengths and types of spacer arms, such as NHS-haloacetyl, NHS-maleimide, and NHS-pyridyldithiol cross-linkers.
Exemplary cross-linkers that are useful in operatively linking the recombinant cleavage domains and nucleic acid binding domains provided herein are set out herein are shown in Table 1.
Alternatively, the recombinant nucleases provided herein can be operatively linked to a nucleic acid binding domain via a non-covalent association. In some embodiments, each of the nuclease domain and the nucleic acid binding domain can include a “linkage domain,” that wherein the linkage domain of the nuclease and the linkage domain of the nucleic acid binding domain together form a “binding pair” capable of non-covalent binding with each other. Several “binding pairs” can be used to operatively link the recombinant nucleases and nucleic acid binding domains provided herein, including but not limited to a leucine zipper (e.g., Fos/Jun), streptavidin/strep-tag, nanobody/peptide, an affinity clamp, or the like. The binding pair may also be designed heterodimer domains (DHDs), such as DHD65a/b and DHD154a/b. A number of DHDs are set out in Chen et al., “Programmable design of orthological protein heterodimers”, Nature 163:106-110 (2019).
In some embodiments, the recombinant nucleases or the recombinant nucleases operatively linked to a nucleic acid binding domain are modified by one or more polyethylene glycan moieties. In some embodiments, pegylation of the isolated recombinant nuclease proteins or recombinant nuclease-nucleic acid binding domain proteins improves stability during delivery of the proteins to a cell. In some embodiments, pegylation of the isolated recombinant nuclease proteins or recombinant nuclease-nucleic acid binding domain proteins increases genome editing after delivery of the proteins to a cell.
In some embodiments, the pegylation is at the N-terminus of the recombinant nuclease protein or of the recombinant nuclease-nucleic acid binding domain proteins. In other embodiments, pegylation is at the C-terminus of the recombinant nuclease protein or of the recombinant nuclease-nucleic acid binding domain proteins. In some embodiments, one or more PEG moieties is attached between the N- and C-termini of the recombinant nuclease protein. In some embodiments, one or more PEG moieties is attached between the N- and C-termini of the nucleic acid binding domain protein. In other embodiments, pegylation is within or at the ends of the linker between the recombinant nuclease and the nucleic acid binding domain. In some embodiments, pegylation is at the N-terminus and/or the C-terminus of the recombinant protein containing an alternative nuclease sequence provided herein. In other embodiments, one or more PEG moieties is attached between the N- and C-termini of the recombinant protein containing an alternative nuclease sequence provided herein.
Exemplary pegylation reagents include, without limitation, NHS ester-(PEG)n, thiol-(PEG)n, and methoxy-(PEG)n compounds. In some embodiments, the recombinant proteins provided herein may be pegylated using, without limitation, mPEG12-NHS, mPEG8-NHS, mPEG4-NHS, mPEG-5K-NHS, mPEG12-SH, mPEG-2K-SH, mPEG-5K-SH, mPEG10K-SH, mPEG-20K-SH, mPEG-40K-SH, and mPEG-B40K-SH.
In some embodiments, the nucleic acid binding domain described herein is transcription activator-like effector (TALE) deoxyribonucleic acid binding domain (DBD). In some embodiments, the TALE DBD is a T-less TALE DBD. In some embodiments, the TALE is derived from Xanthomonas, Ralstonia, or Burkholderia. In some embodiments, the TALE is derived from Ralstonia solanacearum. In some embodiments, the TALE is derived from Burkholderia rhizoxinica. In some embodiments, the TALE is derived from a marine organism (e.g., MOrTL1 or MOrTL2). See, e.g., de Lange et al., Nucleic Acids Research, 43(20): 10065-10080 (2015), which is incorporated herein by reference in its entirety. In some embodiments, the nucleotide sequence encoding the TALE shares at least about 90% sequence identity with a nucleotide sequence encoding a naturally-occurring TALE. In some embodiments, the TALE shares at least about 90% sequence identity with a naturally-occurring TALE polypeptide sequence.
In other embodiments, the nucleic acid binding domain can include, for example, the DNA binding domain of a zinc finger protein. Zinc finger binding domains useful in the embodiments provided herein are well-known in the art and include, but are not limited to, those described in U.S. Pat. Nos. 5,198,346, 8,106,255, 10,808,020, U.S. Patent Application Publication No. 2011/0281306, and the like. In some embodiments, the nucleic acid binding domain can be a dCas9 (“dead” Cas9), e.g., as described in European Patent No. EP3241092.
In some embodiments, the nucleic acid binding domain binds to a target nucleic acid sequence in a nucleic acid molecule. In some embodiments, the cleavage domain cleaves the nucleic acid molecule when the nucleic acid binding domain is bound to the target nucleic acid sequence.
In some embodiments, the nucleic acid binding domain comprises one or more repeat units. In some embodiments, each of the one or more repeat units is 30 amino acids to 45 amino acids in length, and wherein each repeat unit recognizes a nucleotide base. In some embodiments, each of the one or more repeat units is 32 amino acids to 40 amino acids in length. In some embodiments, at least one repeat unit is a non-naturally occurring repeat unit.
In some embodiments, the nucleic acid binding domain binds to a DNA target sequence. In some embodiments, the nucleic acid binding domain binds to a DNA target sequence and the cleavage domain cleaves DNA.
In another aspect, the present disclosure provides a nucleic acid encoding the recombinant protein described herein.
In another aspect, the present disclosure provides a vector comprising the nucleic acid described herein.
In another aspect, the present disclosure provides a cell comprising the recombinant protein, the nucleic acid, or the vector described herein.
In some embodiments, the cell is a prokaryotic cell. In some embodiments, the cell is a eukaryotic cell. In some embodiments, the cell is a plant cell, a yeast cell, an insect cell, or a mammalian cell. Preferably, the cell can be a mammalian cell such as an immune cell (e.g., a T-cell, a B-cell, an NK cell, a macrophage, a dendritic cell, or the like), or a pluripotent cell (e.g., an embryonic stem cell, an adult stem cell, a mesenchymal stem cell, a placental stem cell, a stem cell derived from Wharton’s Jelly, an induced pluripotent stem cell (iPSC), or the like), or other type of mammalian. Other cells useful in the embodiments provided herein include, but are not limited to, CHO cells, HEK-293 cells.
In some embodiments, the cell further comprises a donor nucleic acid, such as a donor DNA and/or a donor RNA.
In some embodiments, the cell is genetically modified.
In another aspect, the present disclosure provides a method of modifying a genome comprising contacting a cell with the recombinant protein described herein.
In another aspect, the present disclosure provides a method of genetically altering a cell, comprising contacting the cell with a recombinant protein described herein under conditions such that the recombinant protein binds a target DNA sequence in the cell.
In another aspect, the present disclosure provides a method of modifying a genome comprising contacting a cell with the nucleic acid or the vector described herein. In some embodiments, this disclosure relates to a vector comprising a promoter operably linked to the nucleic acid. In some embodiments, this disclosure related to a cell comprising one or more recombinant proteins, nucleic acids, and/or vectors as described herein. In some embodiments, this disclosure relates to a cell line comprising a plurality of cells as described herein. In some embodiments, the cell is a bacterial cell, a plant cell, a yeast cell, an insect cell, or a mammalian cell.
In another aspect, the present disclosure provides a method of genetically altering a cell, comprising contacting the cell with the nucleic acid or the vector described herein under conditions such that the recombinant protein is expressed and binds a target DNA sequence in the cell. In some embodiments, the cell is a bacterial cell, a plant cell, a yeast cell, an insect cell, or a mammalian cell.
In some embodiments, the nucleic acid or vector comprises RNA. In some embodiments, the nucleic acid or vector comprises DNA.
In another aspect, the present disclosure provides a method for modifying the genome of a cell, the method comprising: introducing into the cell a recombinant protein described herein, or a nucleic acid encoding a recombinant protein described herein, where the recombinant protein binds to an intracellular nucleic acid binding site, and wherein binding of the recombinant protein with the intracellular nucleic acid binding site results in cleavage of the intracellular nucleic acid binding site and modification of the genome of the cell.
In some embodiments, contacting the cell with the recombinant protein comprises transfecting the cell with a nucleic acid encoding the recombinant protein. In some embodiments, this disclosure relates to a genetically modified cell that was modified by a method as described herein.
In some embodiments, the method further comprises introducing into the cell a donor DNA, such that at least a portion of the donor DNA is inserted into the genome of the cell at the intracellular nucleic acid binding site.
In some embodiments, two or more recombinant proteins or two or more nucleic acids encoding a recombinant protein are introduced into the cell, wherein each recombinant protein binds to and cleaves an intracellular nucleic acid binding site.
In some embodiments, modification the genome of a cell comprises double stranded cleavage of an intracellular nucleic locus.
In some embodiments, the intracellular nucleic locus is a chromosomal locus.
In some embodiments, the genetic modification comprises a knock-in. In some embodiments, the genetic modification comprises a knock-out. In some embodiments, the genetic modification comprises a mutation.
In some embodiments, the genetic modification is achieved via homologous recombination.
In another aspect, the present disclosure provides a kit comprising a first recombinant protein described herein or a first nucleic acid described herein, and at least one reagent for making or using the recombinant protein.
In some embodiments, the kit comprises a vector comprising the nucleic acid described herein.
In some embodiments, the kit further comprises a second recombinant protein or a second nucleic acid, as described herein.
In some embodiments, the at least one additional reagent is selected from a transfection reagent, a DNA cloning reagent, primers to the first and/or second nucleic acid, a control nucleic acid, a third nucleic acid encoding a reporter, and/or a vector.
In another aspect, the present disclosure provides a method of treating a disease or disorder treatable by genetic modification, the method comprising contacting a cell with a recombinant protein described herein, or a nucleic acid encoding a recombinant protein described herein, under conditions such that the recombinant protein is expressed and binds to and cleaves a target DNA sequence in the cell, thereby genetically modifying the cell.
In some embodiments, the method further comprises introducing into the cell a donor DNA, such that at least a portion of the donor DNA is inserted into the genome of the cell at the intracellular nucleic acid binding site.
In some embodiments, modification the genome of a cell comprises double stranded cleavage of an intracellular nucleic locus.
In some embodiments, the intracellular nucleic locus is a chromosomal locus.
In some embodiments, the genetic modification comprises a knock-in. In some embodiments, the genetic modification comprises a knock-out. In some embodiments, the genetic modification comprises a mutation.
In some embodiments, the method further comprises administering the genetically modified cell to a patient. Accordingly, in some embodiments, the genetic modification of the cell is performed ex vivo or in vitro.
In some embodiments, the recombinant protein or nucleic acid is administered to a patient. Accordingly, in some embodiments, the genetic modification of the cell is performed in vivo.
In some embodiments, the disease or disorder described herein is cancer, beta-thalassemia, sickle cell disease, hemophilia, blindness, Leber congenital amaurosis, human immune deficiency syndrome (HIV), cystic fibrosis, Duchenne’s muscular dystrophy, Huntington’s disease, familial hypercholesterolemia, Alzheimer’s disease, retinitis pigmentosa, retinal dystrophy, diabetes, autism spectrum disorder, hypertrophic cardiomyopathy, or Tay-Sachs disease.
In certain embodiments, the disease or disorder described herein is a blood cancer. In some embodiments, the disease or disorder described herein is a leukemia, lymphoma, myeloma, or myelodysplasia, including without limitation B-cell leukemias, B-cell acute lymphoblastic leukemia, B-cell lymphomas, B-cell non-Hodgkin’s lymphoma, follicular lymphoma, mantle cell lymphoma, T-cell lymphomas, Hodgkin’s lymphoma and multiple myeloma. In certain embodiments, the disease or disorder described herein is a solid tumor cancer such as, without limitation, lung cancer, ovarian cancer, cervical cancer, liver cancer, glioma, glioblastoma, prostate cancer, renal cancer pancreatic cancer, gastric cancer, breast cancer, colorectal cancer, melanomas or sarcomas.
In some embodiments, the recombinant protein described herein, when treated to a group of cells (e.g., immune cells, such as T cells), is capable of maintaining or increasing the amount of CD8+ cells in the group of cells. In some embodiments, the recombinant protein described herein, when treated to a group of cells (e.g., immune cells, such as T cells), is capable of maintaining or increasing the ratio of CD8+vs. CD4+ cells in the group of cells. In some embodiments, the recombinant protein described herein, when treated to a group of cells (e.g., immune cells, such as T cells), is capable of increasing the amount of CD8+ cells in the group of cells to at least 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, or more than the amount of CD8+ cells in the group of cells treated with, e.g., a CRISPR editing tool targeting the same locus
In another aspect, the present disclosure provides a composition comprising the recombinant protein described herein for treating a group of cells or a subject to maintain or increase the amount of CD8+ cells and/or the ratio of CD8+ cells vs. CD4+ cells in the group of cells or the subject.
In another aspect, the present disclosure provides a method of maintaining or increasing the amount of CD8+ cells and/or the ratio of CD8+ cells vs. CD4+ cells in a group of cells or a subject, the method comprising treating the group of cells or the subject a composition comprising the recombinant protein described herein.
One skilled in the art would understand that descriptions of making and using the particles described herein is for the sole purpose of illustration, and that the present disclosure is not limited by this illustration.
The Alternative Nucleases (ANs) candidate sequences were identified using a BLAST sequence comparison algorithm, available at the NCBI web site at ncbi.nlm.nih.gov/BLAST, to search proteins having certain sequence homology to Fokl or Clo51. Default algorithm parameters were adjusted to increase Max Target Sequences to 1000 to list identified homologs.
Sequences with a percent identity of 60% or less to cleavage domain of Fokl or Clo51 were analyzed further. Table 2 provides the AN number, source organism, percent identity to Fokl and Clo51, percent identity to AN3 and AN14, Accession number, SEQ ID NO, and amino acid sequence for some of the candidate sequence. Other such candidate AN sequences are provided in Table 3, FIG. 10A and SEQ ID NOs: 3-259, 282, and 296-299. Table 3 provides the AN number, source organism, percent identity to Fokl and Clo51, percent identity to AN197, Accession number, SEQ ID NO, and amino acid sequence for candidate nuclease sequences.
The putative N-terminus of each nuclease was determined by using the Multiple Alignment tool with the Blast algorithm, available at ncbi.nlm.nih.gov/tools/cobalt/cobalt.cgi?LINK LOC=BlastHomeLink, by aligning multiple sequences together based on similarity. Since there is no existing structure model for most of the AN, new AN sequences were then aligned against Fokl and Clo51 amino acid sequences (SEQ ID NOs: 1 and 2, respectively) to predict its N-terminal sequence.
AN sequences were reverse-translated into the corresponding encoding DNA sequences. An adaptor for GOLDENGATE™ cloning containing an AarI restriction enzyme recognition site was added to the N-terminus of the encoding DNA sequences (see SEQ ID NO: 262). A C-terminal nuclear localization signal (NLS), stop codon, and priming site for adding a polyA tail was added to the C-terminus of the encoding DNA sequences (see SEQ ID NO: 263). The sequences were then optimized to contain human codons using the Thermo Fisher Scientific GENEART™ tool. The new human codon optimized DNA sequence was copied for reference, and all constructs were ordered as sequence confirmed plasmids from GeneArt.
Plasmids containing the optimized AN sequences were engineered to include a TALEN nucleic acid binding domain using standard molecular biology techniques.
An AAVS1 (Adeno-Associated Virus Integration Site 1) sequence was chosen as the target for screening the AN due to previously demonstrated high efficiency in editing by Fokl. Therefore, a separate fragment spanning either the forward or reverse direction of a TALEN (Transcription Activator-Like Effector Nucleases) AAVS1 RVD sequence was generated by a PCR (Polymerase Chain Reaction) using sequence verified Fokl TALEN plasmids engineered to recognize the AAVS1 target site (Forward and Reverse) (see SEQ ID NOs: 264-281).
The PCR products of the cloning reactions described above were further processed by performing another amplification reaction with primers that add a polyA tail to the PCR products. The PCR reaction products for each AN sequence were verified using gel electrophoresis.
mRNA Generation/Purification
IVT reactions were set up using the MMESSAGE MMACHINE® T7 Ultra kit (Thermo Fisher Scientific, Cat. AMB13455) according to the manufacturer’s protocol. IVT reaction proudcts were purified using the KINGFISHER™ Flex instrument and a DYNABEADS™ MYONE™ Carboxylic Acid bead (Thermo Fisher Scientific, Cat. 65012) cleanup protocol. Samples were eluted in 30 μL of Ultrapure water. Concentration was determined using a QUANT-IT™ RNA Assay BR kit (Thermo Fisher Scientific Cat. Q10213) on a spectrophotometer, with samples measured in duplicate. mRNA samples were also run on a 1.2% GP gel.
100 ng of mRNA for each the nuclease (e.g., AN recombinant protein or Fokl TALEN) arms, e.g., a forward and a reverse AN recombinant protein or Fokl nuclease respectively each an RVD that specifically binds to a target half site within the target site (200 ng of mRNA in total for each transfection) were used for transfection. All transfections were done in duplicate for each nuclease pair tested. Approximately fifty thousand HEK293FT cells were used for each transfection. The cells were maintained at 37° C. in culture medium. Each transfection utilized 10 μL NEON™ Transfection System kit (Thermo Fisher Scientific cat. MPK1025) and NEON™ Transfection System (Thermo Fisher Scientific, MPK5000). The cells were recovered in DMEM growth media in 96-well flat bottom plates at 37° C. Transfected cells were allowed to recover for 48-72 hours before checking for editing.
Editing was tested using a genomic cleavage detection assay. The media was first carefully drained from the plates and 20 μL of lysis buffer (with 0.4 μL of Proteinase K) was added to each well. The cells and lysis buffer were allowed to rest at 37° C. for 2-3 minutes before being gently removed into a 96-well microamp half-skirt plate. The plate was sealed and loaded onto a PCR machine to lyse using the protocol: incubating at 68° C. for 15 min, at 95° C. for 10 min and then holding at 4° C.
After lysing, PCR reaction products were set up using GCD AAVS1 primer pair provided in the GCD kit. The PCR reaction mixtures consisted of: 25 μL of AMPLITAQ™ Gold 360 Master Mix (Thermo Fisher Scientific, Cat. 4398790), 23 μL of Ultrapure Water, 1 μL of GCD AAVS1 F/R primer mix, and 1 μL of cell lysate. The PCR protocol included: incubating the PCR reaction mixture at 95° C. for 10 min, followed by 40 cycles of incubations, each cycle including incubating the reaction mixture at 95° C. for 30 s, at 55° C. for 30 s, and then at 72° C. for 30 s. After the 40 cycles, the reaction mixture was further incubated at 72° C. for 7 min, at 95° C. for 5 min, at 85° C. for 5 s, at 25° C. for 5 s, and then held at 4° C.
Once finished, the PCR reaction mixtures were kept on ice. A 48-well 2% Ex-gel (Thermo Fisher Scientific, Cat. G800802) was used to analyze the PCR samples to confirm that the PCR products have the correct size (400 bp). An enzymatic digest was performed for each PCR reaction using: 6 μL of Ultrapure water, 1 μL of GCD enzyme buffer, 1 μL of GCD T7 endonuclease enzyme mix, and 2 μL of PCR reaction.
The reaction was at 37° C. for 1 hour. After the reaction the total mixture volume of 10 μL was loaded onto a 48 well 2% EX-gel for analysis. If the sample was edited, two bands (150 bp and 250 bp) would appear beneath the larger, uncut sample band (400 bp). The brighter the lower bands, the more population of the sample were edited. The editing efficiency was analyzed by the ALPHAIMAGER® HP software.
Cloning the AN into pCMV
Each of the top performing AN sequences was further cloned (both the forward and reverse chains of the constructs) into a modified pCMV vector. Starting from template DNA including the AN197 nuclease domain operatively linked to TAL binding domains that specifically bind to the AAVS1 locus, used in the addition of the AAVS1 binding sites to the AN197 cleavage domains, PCR was used to replace the TALEN domains specific for the AAVS1 locus with TALEN domains specific for the TAC48 locus.
The PCR product was run on a 2% EX gel to check for laddering and having the correct size (3.5 kb), then digested with 1 μL of Dpn1 at 37° C. for 2 hours. The product was then purified using a PURELINK™ Quick PCR Purification kit. The modified pCMV vector was linearized as follows: 5 μl of modified pCMV plasmid, 3 μL of Buffer G, 2 μL of BsaI restriction enzyme, and 20 μL of water.
A 2% EX-GEL™ agarose gel (Thermo Fisher Scientific, cat. G401002) was used to check the digested fragments have the correct sizes, which should be 3292 bp and 500 bp. and the linearized plasmid was purified using a PURELINK™ Quick PCR Purification kit (Thermo Fisher Scientific, cat. K310001). The purified pCMV linear vector was then diluted to 50 ng/μL.
A Seamless Cloning reaction (Thermo Fisher Scientific, cat. A13288) was set up to include: 8 μL UltraPure Water, 1 μL of linear pCMV vector, 5 μL of PCR-purified AAVS1-AN construct (forward or reverse), 4 μL of 5× Enzyme Buffer, and 2 μL of 10× Enzyme mix.
The reaction mixture was incubated at room temperature for 30 min. Fifty microliters of DH10b (Thermo Fisher Scientific, cat. 12331013) cells were then mixed with 5 μL of Seamless reaction (50 μL cells per Seamless reaction; multiple tubes would be used for multiple Seamless reactions). The reaction mixture was then recovered in SOC medium at 37° C. for 1 hour. One hundred microliters of the reaction mixture were then plated onto LB-AMP agar plates and let sit at 37° C. for 14-20 hours. Each of resulting colonies was picked into 5 mL of LB-AMP media for grow overnight under shaking at 37° C. for 14-20 hours. Once finished, the DNA components were extracted by miniprep using the PURELINK™ Quick Plasmid Miniprep Kit (Thermo Fisher Scientific, cat. K210011), and then sequenced using standard BIGDYE™ sequencing kit, according to manufacturer’s protocol (Thermo Fisher Scientific, Cat. 4337455) and the sequencing primers in the Supplementary Materials. Plasmids were verified using the Geneious Prime software.
Testing at the TRAC locus
Top performing AN sequences were tested at the TRAC locus to determine if they contained any target-specific bias. To generate the TRAC RVD (F and R) PCR fragments used a sequence confirmed TRAC48 plasmid and the primers TD1F2 and TD8 RVD R (See SEQ ID NOs: 284-295). The PCR reaction setup and PCR cycling were the same as making the AAVS1 RVD fragments.
The AN fragments (containing the TALEN-derived nucleic acid binding C-term domain and N-term cleavage domain (AN)) were created by using a sequence verified AAVS1-AN plasmid and the primers TD8F3 and TD8R2. The reactions were: 25 μL of 2× Phusion Flash PCR Master Mix (F-548), 22.5 μL of UltraPure Water, 1 μL of each primer at 10 μM, and 0.5 μL of AN AAVS1 plasmid. The PCR protocol was: incubating the PCR reaction mixture at 98° C. for 1 min, followed by 25 cycles of incubations, each cycle including incubating the reaction mixture at 98° C. for 1 s, 64.7° C. for 5 s, and at 72° C. for 15 s. After the 25 cycles, the reaction mixture was further incubated at 72° C. for 2 min, and then held at 4° C.
PCR product was run on a 2% gel to check for correct size (1.1 kb), then digested using 1 μL Dpn1 for 2 hours at 37° C., followed by purification using a PURELINK™ Quick PCR Purification kit.
The GOLDENTGATE™ cloning reaction mixture was set up using BsaI as follows: 50 ng of AN plasmid, 50 ng of purified TALEN RVD for the TRAC target (forward or reverse), 2 μL of Buffer G, 2 μL of BsaI restriction enzyme, 3 μL of ATP, 1 μL of T4 ligase, and water to make a total volume of 20 μL.
The PCR protocol was: incubating the PCR reaction mixture at 37° C. for 10 min, followed by 15 cycles of incubations, each cycle including incubating the reaction mixture at 37° C. for 1 min, and at 16° C. for 1 min. After the 15 cycles, the reaction mixture was further incubated at 37° C. for 5 min, at 65° C. for 10 min, and then held at 4° C.
After the GOLDENGATE™ cloning reaction was complete, the reaction products encoding the recombinant proteins with nucleic acid binding sites specific for the TRAC locus were used in transfection reactions as described elsewhere herein. Transfected cells were assayed using the genomic cleavage detection (GCD) assay as described elsewhere herein, using the GCD TRAC F and GCD TRAC R primers.
The Leukopak from healthy donors were purchased from AllCells Inc. The peripheral blood mononuclear cells were isolated by density gradient centrifugation. Cells were activated with the Dynabeads (1:1 beads: cell) A Human T-Activator CD3/CD28 (Thermo Fisher Scientific) in CTS OpTimizer medium (Thermo Fisher Scientific, Catalog #A3705001) supplemented with 2% human serum (Valley biomedical) with 200 U ml-1 IL-2 (Thermo Fisher Scientific, Catalog #PHC0021) at a density of 106 cells per ml. The medium was changed every 2 days, and cells were re-plated at 106 cells per ml. NALM6-Fluc-GFP cell line was purchased from the Imanis Life Sciences.
T cell basal and post-activation phenotypes were characterized by flow cytometry staining with PE conjugated TCR alpha/beta antibody (Thermo Fisher Scientific, Catalog #MA1-10455), and analyzed with an Attune NxT flow cytometer (Thermo Fisher Scientific). All data were analyzed with the Flow Jo_V10 software (Tree Star Inc.).
The following mAbs against human proteins were from Thermo Fisher Scientific: V5—PE (Catalog #12-6796-42), CD25 AF-700 (Catalog #56-0259-42), CD69 eFluor450 (Catalog #48-0699-42), CD62L APC (Catalog #17-0629-42), CD95 eFluor450 (Catalog #48-0959-42), LAG-3 eFluor506 (Catalog #69-2239-42), PD-1 SB702 (Catalog #67-2799-42), TIM3 APC (Catalog #61-3109-42), TCR α/β SB436 (Catalog #62-9986-42), CD4 APC-780 (Catalog #47-0049-42), CD8 eFluor450 (Catalog #48-0088-42). SYTOX™ Red Dead Cell Stain was used as a viability marker (Thermo Fisher Scientific, Catalog #S34859). Samples were analyzed with an Attune NxT flow cytometer (Thermo Fisher Scientific). All data were analyzed with the Flow Jo_V10 software (Tree Star Inc.).
The Activated T cells were pelleted and resuspended at 4×107 cells/ml in R buffer (Neon Transfection System Kit, Thermo Fisher Scientific). Two hundred nanograms of the TALEN alternative nucleases mRNA were added to 10 μL (2×105) on ice. Single arm TALEN mRNA (i.e., mRNA only encoding one monomer of the dimeric pair) was used as a control in some experiments. This mixture was electroporated with the Neon Transfection system (Thermo Fisher Scientific) using program 16 (two pulses of 1400 V and 20 ms pulse width). T cells were recovered in warm CTS OpTimizer medium containing 200 U/mL IL-2.
Gene editing was evaluated by the genome cleavage detection (GCD) assay using GeneArt® Genomic Cleavage Detection Kit (Thermo Fisher Scientific, USA), a method that detects locus-specific double-stranded break (DSB) formation by direct polymerase chain reaction (PCR) amplification and endonuclease activity that cuts specifically at hetero-duplex mismatches.
T cells from two different donors (donor A and donor B) were electroporated with TALEN alternative nuclease 197 or Fokl TALEN mRNA targeting human AAVS1 locus using Neon Transfection system. A negative control sample for gene modification was also prepared by transfecting with TALEN single arm mRNA. The above samples were PCR amplified using the same set of primers flanking the region of interest. After re-annealing, samples were treated with Detection Enzyme and run on a 2% E-Gel® EX Gel.
TCR α/β knockout test by flow cytometry
The Activated T cells were electroporated with TALEN alternative nucleases 197, 6, 159 and TALEN Fok 1 mRNA targeting human TRAC locus. After 4 days, the TCR α/β knockout frequency was tested by flow cytometry. The TCR α/β knockout efficiency with Fokl TALEN, TALEN alternative nuclease 197, and a CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR Associated Protein 9) in 2 different T cell donors were measured and compared. Each group had two independent electroporation. The TALEN alternative nuclease 197, Fokl TALEN and CRISPR/Cas9—targeted CAR gene integration into the TRAC locus was also tested. Knock-in efficiency was proportional to the AAV6-CAR dosage. These results demonstrate the high efficiency and precision of gene targeting offered by TALEN alternative nuclease 197.
A FACS (Fluorescence-Activated Cell Sorting) analysis of activation, memory and exhaustion markers in T cells (day 5 after transfection) were performed. All the TALEN alternative nuclease 197, Fokl TALEN and CRISPR/Cas9 generated CAR-T (Chimeric Antigen Receptor) cells maintained a phenotype analogous to untransduced T cells, mainly composed of naïve and central memory cells (CD62L+ cells), a phenotype associated with greater in vivo anti-tumor activity.
The Cytotoxicity of CAR-T cells was measured by the in vitro eradication of the CD19-positive NALM6 cell line. For this purpose, a flow cytometry-based assay was used to quantify the number of viable, CD19+ cells. NALM6 (CD19+) cells were almost completely eliminated after 4 hr of co-culturing at effector (E): target (T) ratios of 10:1 and 5:1. Percentage of cell killing, relative to naïve T cells, is shown in FIG. 16 (mean of 3 experiments ±SEM).
New alternative nucleases (ANs) were identified by screening the NCBI database for sequences having certain homology to the restriction endonuclease Fokl or Clo51. As a result, 206 Alternative Nucleases (ANs) were identified and named as AN1-AN206, including three batches: AN14 (including AN1-AN14), AN50 (including AN15-AN64), and AN142 (including AN65-AN206). All these ANs were cloned and further screened for editing activity at AAVS1 target site, a target at which Fokl TALENs achieve 100% editing efficiency (by Sanger sequencing).
FIG. 1 shows an exemplary result of screening of 50 ANs (“the AN50 batch”), using the Genomic Cleavage Detection Kit, to assess cleavage efficiency of the AAVS1 (Adeno-Associated Virus Integration Site 1) target site. Top performing ANs, (e.g., the circled candidates, such as AN18, AN21, AN26, AN33, AN35, and AN46), which showed high editing efficiency, were re-tested to confirm the data repeatability (FIG. 2) and cloned into pCMV plasmid for sequence verification of the constructs.
Similarly, AN6 was identified as a top performing AN (FIG. 3), while AN67, AN70, AN77, AN90, AN111, AN131, AN140, AN159, AN162, and AN197 in the AN142 batch were identified as top performing ANs (FIGS. 4–6). FIG. 7 shows the retest result of these top performing ANs. The tables below the bar graphs in FIGS. 1–7 provide the percent identity of each of the AN sequence in the graph to Fokl and Clo51.
These top performing ANs at the AAVS1 target site were then screened for their activity to the TRAC site, a target of relevance to the CAR-T therapy field (using TRAC48 TALENs). As shown in FIGS. 8–9, ANs acted differently at different targets. AN197 (SEQ ID NO:200) was shown to work well at both AAVS1 and TRAC48 sites (FIG. 9).
The AN197 recombinant protein used in the experiments depicted in FIGS. 6–9 was further optimized by changing its N-terminus sequence. As shown in FIGS. 10A and 10B, the optimization extends the N-terminus of original AN197 (“AN197_I” in FIG. 10A, SEQ ID NO: 200) up to 5 amino acids longer. As shown in FIG. 10A, AN197_ASKTGI extends the N-terminus by 5 amino acids (SEQ ID NO: 299), AN197 SKTGI extends the N-terminus by 4 amino acids (SEQ ID NO: 298), AN197_KTGI extends the N-terminus by 3 amino acids (SEQ ID NO: 297), AN197_TGI extends the N-terminus by 2 amino acids (SEQ ID NO: 282), and AN197_GI extends the N-terminus by 1 amino acid (SEQ ID NO: 296). The optimized AN197 recombinant proteins were tested for their editing efficiency at TRAC15, a target hard to edit for Fokl. It was shown that the original and optimized AN197 recombinant proteins had better editing efficiency than Fokl at the TRAC15 site (FIG. 10A). One exemplary AN197 amino acid sequence is shown in SEQ ID NO: 282. Other exemplary AN197 amino acid sequences are shown in SEQ ID NOS: 296-299. The optimized AN197-based nucleases displayed similar editing efficiencies.
Several top performing ANs were further tested in human primary T cells for their editing efficiency (e.g., at the AAVS1 or TRAC48 site). A GCD assay as described elsewhere herein was used to determine the editing efficiency on the AAVS1 site, while flow cytometry was used for testing the editing on the TRAC48 site.
Surprisingly, as shown in FIGS. 11A, 11B, 12A-12G, 13 and 14, AN197 worked as well (as measured by gene editing efficiency) as Fokl TALEN and CRISPR for TRAC knock out and CAR knock-in in human primary T cells at both the AAVS1 and TRAC48 loci. Furthermore, AN197 CAR-T cells had similar phenotype (read by activation, memory and exhaustion markers) as Fokl TALEN and CRISPR CAR-T (FIG. 15). Interestingly, cells transfected with nucleic acids encoding either Fokl TALEN or an AN197 recombinant protein resulted in a higher number of CD8+ cells than the editing with CRISPR (FIG. 15).
AN197 CAR-T cells had comparable cytotoxicity to target cells as Fokl TALEN CAR-T cells in the killing assay (FIG. 16). Surprisingly, the TALEN-edited cells performed better than the CRISPR-edited cells in this killing assay, probably contributed by the higher amount of CD8+ cells resulted from the former editing. Given the extremely low homology of AN197 to known nucleases such as Fokl and Clo51, it is surprising and unexpected that AN197 not only functioned as well as Fokl TALEN and CRISPR, but further that AN197 showed beneficial properties compared to CRISPR.
TALEN alternative nuclease 197 (TALEN AN197) editing efficiency was tested in several targets (TIM3, B2M, LAG3, PD-1 and AAVS1) in human primary T cells and HEK 293 cells. The selected target pairs were identified from a previous screen to have good editing efficiency. The same protocols as described elsewhere herein were used for the mRNA generation, transfection and GCD assay. Exemplary editing efficiency results for the various targets are shown in FIGS. 17A-17F. All targets showed higher than 80% editing efficiency detected by GCD.
Ten consecutive TALEN AN197 mRNA pairs targeting either B2M, TIM-3, LAG3 or C2TA were electroporated into HEK293 cells or primary human T cells to determine the best editing TALEN AN197 pair for each target. The cells were harvested 2-3 days after electroporation and editing efficiency was determined by the GCD assay. For T cell B2M screening, B2M KO was determined by flow cytometry as described herein. Exemplary results of editing efficiency for the targets in HEK 293 cells is shown in FIGS. 18A-18D. Exemplary results of editing efficiency for the LAG3 and TIM3 targets and B2M KO in primary T cells is shown in FIGS. 19A-19C.
Fifty consecutive TALEN AN197 pairs (each AN197 pair was moved 1 bp to the right along the sequence) targeting near the exon1 region of TRAC. Each pair was transfected into human primary T cells and tested for editing efficiency by both GCD and flow cytometry. Target cleavage by the TALEN AN197 pairs was observed at all fifty sites.
To determine whether multiple genes can be edited at the same time with TALEN AN197, we transfected different concentrations (50 ng, 100 ng, 150 ng of forward and reverse each) of AN197 mRNA targeting TRAC and AN197 mRNA targeting B2M at the same time. TRAC or B2M targeting AN197 mRNA were also electroporated separately to compare the editing efficiency to the multiplex reaction (100 ng of each AN197 forward and reverse). TRAC or B2M knock out efficiencies were determined by flow cytometry, as previously described (B2M-FITC, Thermo Fisher Scientific, Catalog #A15737). As shown in FIG. 20, double knock-outs of TRAC and B2M were readily achieved with the multiplex reaction.
Multiplex editing was also tested by transfecting HEK293T cells with TALEN AN197 pairs targeting different targets at the same time (1 pair, 2 pairs, 3 pairs or 4 pairs). The editing efficiency and cell viability of each combination of transfection was examined. All samples showed similar editing efficiencies, whether they were editing 1, 2, 3 or 4 targets at the same time. The viable cell count decreased slightly with 4 targets combined, possibly because of the increased amount of mRNA used. As shown in FIGS. 26A-26B and 27A-27B, the results demonstrate that TALEN AN197 can edit multiple targets at the same time. This may be particular use for clinical applications where multiple edits are needed.
The TRAC knock out and CAR knock-in efficiencies in human primary T cells was tested with CAR double-strand DNA (dsDNA) donors using the AN197 mRNA or CRISPR/Cas9 RNP systems. To prepare the dsDNA donors, long double-strand HDR templates encoding an anti-CD19 CAR with 500 bp homology arms were synthesized and cloned into a pAAV plasmid, which then served as a template for generating a dsDNA donor. Specific PCR primers targeting the left and right homology arms were synthesized without chemical modifications. Amplicons were generated with Phusion Flash PCR Master Mix (Thermo Fisher Scientific), purified by PureLink™ Pro 96 PCR Purification Kit (Thermo Fisher Scientific), and resuspended in water to 1-3 μg/μl measured by light absorbance on a NanoDrop spectrophotometer (Thermo Fisher Scientific).
HDR templates were mixed and incubated with AN197 mRNA or CRISPR/Cas9 RNPs for at least 5 min prior to mixing with and electroporating into cells. This mixture was electroporated with the Neon Transfection system (Thermo Fisher Scientific) using program 16 (two pulses of 1400 V and 20 ms pulse width). T cells were recovered in warm CTS OpTimizer medium containing 200 U/mL IL-2. At 3 days after electroporation, cells were collected for staining and flow cytometry analysis. In brief, cells were stained TCR α/b, V5 and live—dead dye, then analyzed on an Attune NxT flow cytometer with an automated 96-well sampler (Thermo Fisher Scientific) sampling a defined volume (50-150 μL per well) to obtain quantitative cell counts. Cytometry data were processed and analyzed using FlowJo software (BD Bioscience).
Primary human T cells were transfected TALEN AN197 or CRISPR with both systems targeting TRAC. For AN197, 300 ng of dsDNA donor was used and for CRISPR, 800 ng dsDNA donor was used. We observed 33-36% TCR knock out and CAR knock-in efficiencies with AN197, while the CRISPR efficiency was around 27% in the two donors tested. FIG. 21 shows exemplary results of AN197CAR knock-in with non-viral ds-DNA donor. In other transfection reactions, the AN197 system achieved up to 41.5% CAR knock-in efficiency with non-viral ds-DNA donor.
Primary human NK cells were obtained from healthy donor leukopaks from AllCells Inc. The peripheral blood mononuclear cells were isolated by density gradient centrifugation. NK cells were subsequently obtained by depletion of non-NK cells using the Miltenyi NK cell separation kit (Miltenyi Biotech, Bergisch Gladbach, Germany), according to the manufacturer’s instruction. Freshly isolated NK cells were cultured with Gibco™ CTS™ NK-Xpander™ Medium (A50190, Thermo Fisher Scientific) in the presence of 500 U/ml recombinant human IL-2 (PHC0023, Thermo Fisher Scientific). Every 4-6 days NK cells were expanded until the right exponential growth phase was reached to perform gene editing. After day 5, fresh CTS™ NK-Xpander™ complete medium with fresh IL-2 (500U/mL) was added every 1-2 days as necessary.
The expanded NK cells were pelleted and resuspended at 4×107 cells/ml in R buffer (Neon Transfection System Kit, Thermo Fisher System). Two hundred nanograms of the TALEN alternative nucleases mRNA or and a CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR Associated Protein 9) was added to 10 μL (2×105) on ice. Shocked only was used as a control for all experiments. This mixture was electroporated with the Neon Transfection system (Thermo Fisher Scientific) using program 5 (one pulses of 1700 V and 20 ms pulse width). NK cells were recovered in warm Gibco™ CTS™ NK-Xpander™ Medium containing 500 U/mL IL-2. After 3 days, cells were collected for GCD assay.
Human primary NK cells were Neon electroporated with TALEN AN197 mRNA or CRISPR/Cas9 targeting AAVS1. Cells were collected 3 days after transfection to determine the editing efficiency using the GCD assay. Different amounts of mRNA (100-200 ng) or RNP (1× to 2× payload) were used. A 1× RNP payload was 1.2 micrograms Cas9, 7.5 pmole gRNA. Both systems showed similar editing efficiencies of around 60%. Exemplary results are shown in FIGS. 22A-22D.
TALEN alternative nuclease CAR knock-in with viral donor was performed in NK cells. The expanded NK cells were pelleted and resuspended in R buffer (Neon Transfection System Kit, Thermo Fisher Scientific) electroporated with TALEN AN mRNA or and a CRISPR/Cas9 as described above. The electroporated NK cells were recovered in warm Gibco™ CTS™ NK-Xpander™ Medium containing 500 U/mL IL-2. AAV6-CAR was added in the cell suspension with different multiplicity of infection (MOI). The expansion started immediately after the electroporation with Gibco™ CTS™ NK-Xpander™ Medium (A50190, Thermo Fisher Scientific) in the presence of 500 U/ml recombinant human IL-2 (PHC0023, Thermo Fisher Scientific). The CAR knock-in efficiencies (detected by Flow Cytometry with a V5-PE antibody) were monitored over the course of time (up to Day 28).
AN197 mRNA targeting AAVS1 was transfected into NK cells followed by the addition of AAV6-CAR at different MOI. An increase in CAR+ population was observed with longer culture times. CAR knock-in efficiency was higher in higher AAV6 MOI cells, however over time the knock-in efficiency became similar to the lower AAV6 MOI samples. Exemplary results of AN197 CAR knock-in with viral delivery in NK cells are shown in FIG. 23.
iPSC’s were transfected with TALEN AN197 mRNA targeting either AAVS1 or TRAC with the Neon electroporator. Cells were harvested 7 days after electroporation for GCD assay analysis.
iPSC’s were cultured in StemFlex Medium (Thermo Fisher Scientific) in rhLaminin-521 coated plates at 37° C., 5% CO2. 100 ng of each mRNA pair targeting either TRAC or AAVS1 were transfected into 40,000-200,000 cells using the neon electroporator (program 2). Immediately after transfection, the cells were transferred to StemFlex Medium containing 1× RevitaCell™ Supplement (Thermo Fisher Scientific). 24 hours later, the media was changed to StemFlex Medium without RevitaCell™ Supplement. Seven days after transfection, the cells were harvested for GCD assay. Exemplary results are shown in FIGS. 24A-24D. For both AAVS1 and TRAC targets, about 60% editing efficiency was observed.
TALEN AN197 proteins were produced in E. coli BL21(DE3) cells transformed with a pET28a plasmid containing the AN197 sequence (AAVS1 TALF or TALR). A single colony was grown overnight (12-14 hours) in 100 mL BRM supplemented with 50m/m1 kanamycin at 37° C. with shaking. The following day, 20 ml of the overnight culture was added to each 1 Liter BRM supplemented with 50m/mlkanamycin and incubated at 37° C. with shaking until the optical density at 600 nm (0D600) reached 0.4-0.6. The culture was then incubated at 22° C. to an OD600 of 0.8. AN197 protein was induced by the addition of isopropyl β-d-1-thiogalactopyranoside (IPTG) to a final concentration of 0.5 mM for 16 ˜18 hours at 22° C. with shaking.
The cells were harvested by centrifugation at 5,000 rpm for 30 minutes at 4° C. and the pellet was resuspended in 3 volumes lysis buffer (25 mM Tris-HCl, pH 8.0, 300 mM NaCl, lx Protease Inhibitor Cocktail (Pierce), 1 mM TCEP, 0.5% Triton-X100,10% glycerol). Cells were lysed 3 times using a microfluidizer at 20,000 psi. After the cell debris was removed by centrifugation at 24,200 RCF for 1 hour at 4° C., AN197 protein in the soluble fraction was first purified using the AKTA pure chromatography system (Cytiva) with a 10m1POROS™ 50 HE column. The cleared lysate was loaded onto the column, washed with Buffer A (25 mM Tris-HCl pH 8.0, 300 mM NaCl, 1 mM TCEP, 10% glycerol), and eluted with linear salt gradient up to 1 M NaCl. The peak fractions with major AN197 proteins were pooled and further purified with a 5 ml HisPur™ Ni-NTA column. After loading, the column was first washed with Buffer C (25 mM Tris-HCl pH 8.0, 1M NaCl, 1 mM TCEP, 10% glycerol) and subsequently with buffer D (40 mM imidazole, 25 mM Tris-HCl pH 8.0, 500 mM NaCl, 1 mM TCEP, 10% glycerol), and eluted with linear gradient up to 0.5M imidazole. Protein fractions were subsequently concentrated and buffer exchanged to 25 mM Tris-HCl, pH 8.0, 1 mM TCEP, 250 mM NaCl, and 50% glycerol, using an Amicon Ultra15 Centrifugal Filter Unit (EMD Millipore). Protein samples were filtered through a 0.22 μM low-protein binding filter (EMD Millipore), aliquoted, and stored at −80° C. Protein purities were assessed by SDS-PAGE and concentration were measured by Bradford assay.
With first the Heparin column followed by a Ni-NTA purification column in the AKTA pure chromatography system, a pure TALEN AN197 protein preparation was obtained (see FIG. 25B).
To test whether the TALEN AN197 protein was functional, an in vitro functional assay was performed. Purified AN197 protein was mixed with a substrate that contained the same two AN197 binding sites (palindromic) with 16 bp spacing. The in vitro cleavage assay was performed by mixing 100 ng of PCR amplified target DNA substrate, 50 mM potassium acetate, 20 mM Tris-acetate, 10 mM magnesium acetate, 100m/m1 BSA, 1 mM DTT at pH 7.9 and purified AN197 proteins in 10 μl total reaction volume each. Cleavage reactions were incubated at 25° C. for 1 hour or 37° C. for 15 to 60 minutes. Cleavage products were separated by E-Gel™ EX 2% Agarose Gels (Invitrogen). The gel image was captured and processed with iBright imaging system (Invitrogen). The substrate fragment contains two target sites in palindrome with 16 bp spacing in between. As shown in FIG. 25A, purified TALEN AN197 protein efficiently cuts the target substrate, confirming its functional activity. The cutting pattern and resulting fragment termini from the AN197 nuclease is similar to that of Fokl.
To test the activity of the isolated TALEN AN197 protein in cells, purified TALEN AN197 protein was introduced into cells using the Neon™ Transfection System (Thermo Fisher Scientific). Electroporation of HEK293FT cells with the purified TALEN AN197 protein resulted in about 35-40% editing as detected by GCD assays. While the purified protein was soluble in high salt buffer, the protein was somewhat less stable in the Neon electroporation buffer (R buffer) leading to some precipitation of the protein. To improve the stability of purified TALEN AN197 under these conditions, the protein was PEGylated using pegylating reagents such as PEG-SH and PEG-NHS reagents. When AAVS1 targeting TALEN AN197 protein was pegylated with mPEG-5K-SH, we obtained up to 75% editing of the target site in HEK293FT cells. Delivering PEGylated TALEN AN197 protein to cells resulted in up to 60% cell editing in primary human T cells and up to 48% cell editing in iPSCs. This demonstrates that the PEGylated TALEN AN197 protein is functional in multiple cell types.
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