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  • C12N15/09—Recombinant DNA-technology
  • C12N15/10—Processes for the isolation, preparation or purification of DNA or RNA
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  • C12N15/09—Recombinant DNA-technology
  • C12N15/11—DNA or RNA fragments; Modified forms thereof; Non-coding nucleic acids having a biological activity
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  • C12N15/00—Mutation or genetic engineering; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification; Use of hosts therefor
  • C12N15/09—Recombinant DNA-technology
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  • C12N15/09—Recombinant DNA-technology
  • C12N15/11—DNA or RNA fragments; Modified forms thereof; Non-coding nucleic acids having a biological activity
  • C12N15/62—DNA sequences coding for fusion proteins
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  • C12N9/14—Hydrolases (3)
  • C12N9/16—Hydrolases (3) acting on ester bonds (3.1)
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  • C12N9/00—Enzymes; Proenzymes; Compositions thereof; Processes for preparing, activating, inhibiting, separating or purifying enzymes
  • C12N9/14—Hydrolases (3)
  • C12N9/78—Hydrolases (3) acting on carbon to nitrogen bonds other than peptide bonds (3.5)
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
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  • C12N2310/00—Structure or type of the nucleic acid
  • C12N2310/10—Type of nucleic acid
  • C12N2310/20—Type of nucleic acid involving clustered regularly interspaced short palindromic repeats [CRISPR]
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  • C12N2800/00—Nucleic acids vectors
  • C12N2800/80—Vectors containing sites for inducing double-stranded breaks, e.g. meganuclease restriction sites
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
  • Y02A50/30—Against vector-borne diseases, e.g. mosquito-borne, fly-borne, tick-borne or waterborne diseases whose impact is exacerbated by climate change

Definitions

• Targeted editing of nucleic acid sequences is a highly promising approach for the study of gene function and also has the potential to provide new therapies for human genetic diseases.
• An ideal nucleic acid editing technology possesses three
• NHEJ and HDR are stochastic processes that typically result in modest gene editing efficiencies as well as unwanted gene alterations that can compete with the desired alteration. Since many genetic diseases in principle can be treated by effecting a specific nucleotide change at a specific location in the genome (for example, a C to T change in a specific codon of a gene associated with a disease), 9 the development of a programmable way to achieve such precision gene editing would represent both a powerful new research tool, as well as a potential new approach to gene editing-based human therapeutics.
• Nucleic acid programmable DNA binding proteins such as the clustered regularly interspaced short palindromic repeat (CRISPR) system is a recently discovered prokaryotic adaptive immune system 10 that has been modified to enable robust and general genome engineering in a variety of organisms and cell lines.
• CRISPR-Cas CRISPR associated
• sgRNA RNA molecule
• a Cas protein then acts as an endonuclease to cleave the targeted DNA sequence.
• the target DNA sequence must be both complementary to the sgRNA, and also contain a "protospacer-adjacent motif (PAM) at the 3 '-end of the complementary region in order for the system to function.
• PAM protospacer-adjacent motif
• S. pyogenes Cas9 has been mostly widely used as a tool for genome engineering.
• This Cas9 protein is a large, multi-domain protein containing two distinct nuclease domains. Point mutations can be introduced into Cas9 to abolish nuclease activity, resulting in a dead Cas9 (dCas9) that still retains its ability to bind DNA in a sgRNA-programmed manner. 16
• dCas9 when fused to another protein or domain, dCas9 can target that protein or domain to virtually any DNA sequence simply by co-expression with an appropriate sgRNA.
• dCas9 complex for genome engineering purposes is immense. Its unique ability to bring proteins to specific sites in a genome programmed by the sgRNA in theory can be developed into a variety of site- specific genome engineering tools beyond nucleases, including deaminases (e.g., cytidine deamianses), transcriptional activators, transcriptional repressors, histone-modifying proteins, integrases, and recombinases. 11 Some of these potential applications have recently been implemented through dCas9 fusions with transcriptional activators to afford RNA-guided transcriptional activators, 17 ' 18 transcriptional repressors, 16 ' 19 ' 20 and chromatin modification enzymes. 21 Simple co-expression of these fusions with a variety of sgRNAs results in specific expression of the target genes. These seminal studies have paved the way for the design and construction of readily programmable sequence-specific effectors for the precise manipulation of genomes.
• deaminases e.g.,
• nucleic acid programmable DNA binding protein for example CasX, CasY, Cpfl, C2cl, C2c2, C2c3, or Argonaute protein
• a cytidine deaminase domain fused by a linker are useful for efficiently deaminating target cytidine residues.
• Other aspects of this disclosure relate to the recognition that a nucleobase editing fusion protein with a cytidine deaminase domain fused to the N-terminus of a napDNAbp via a linker was capable of efficiently deaminating target nucleic acids in a double stranded DNA target molecule.
• fusion proteins which are also referred to herein as base editors, generate less indels and more efficiently deaminate target nucleic acids than other base editors, such as base editors without a UGI domain.
• Other aspects of this disclosure relate to the recognition that a nucleobase editing fusion protein with a cytidine deaminase domain fused to the N-terminus of napDNAbp via a linker perform base editing with higher efficiency and greatly improved product purity when the fusion protein is comprised of more than one UGI domain.
• Example 17 which demonstrates that a fusion protein (e.g., base editor) comprising two UGI domains generates less indels and more efficiently deaminates target nucleic acids than other base editors, such as those comprising one UGI domain.
• a fusion protein e.g., base editor
• the fusion protein comprises: (i) a nucleic acid programmable DNA binding protein (napDNAbp); (ii) a cytidine deaminase domain; and (iii) a uracil glycosylase inhibitor (UGI) domain, where the napDNAbp is a CasX, CasY, Cpfl, C2cl, C2c2, C2c3, or Argonaute protein.
• the nucleic acid programmable DNA binding protein (napDNAbp) is a CasX protein.
• the CasX protein comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 29 or 30.
• the CasX protein comprises the amino acid sequence of SEQ ID NO: 29 or 30.
• the fusion protein comprises: (i) a nucleic acid programmable DNA binding protein (napDNAbp); (ii) a cytidine deaminase domain; (iii) a first uracil glycosylase inhibitor (UGI) domain; and (iv) a second uracil glycosylase inhibitor (UGI) domain, wherein the napDNAbp is a Cas9, dCas9, or Cas9 nickase protein. In some embodiments, the napDNAbp is a dCas9 protein.
• the napDNAbp is a CasX, CasY, Cpfl, C2cl, C2c2, C2c3, or Argonaute protein.
• the dCas9 protein is a S. pyogenes dCas9 (SpCas9d).
• the dCas9 protein is a S. pyogenes dCas9 harboring a D10A mutation.
• the dCas9 protein comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 6 or 7.
• the dCas9 protein comprises the amino acid sequence of SEQ ID NO: 6 or 7.
• the dCas9 protein is a S. aureus dCas9 (SaCas9d). In some embodiments, the dCas9 protein is a S. aureus dCas9 harboring a D10A mutation. In some embodiments, the dCas9 protein comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 33-36. In some embodiments, the dCas9 protein comprises the amino acid sequence of SEQ ID NO: 33-36.
• the nucleic acid programmable DNA binding protein [0009] In some embodiments, the nucleic acid programmable DNA binding protein
• napDNAbp is a CasY protein.
• the CasY protein comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 31. In some embodiments, the CasY protein comprises the amino acid sequence of SEQ ID NO: 31.
• the nucleic acid programmable DNA binding protein [0010] In some embodiments, the nucleic acid programmable DNA binding protein
• napDNAbp is a Cpfl or Cpfl mutant protein.
• the Cpfl or Cpfl mutant protein comprises an amino acid sequence that is at least 90% identical to any one of SEQ ID NOs: 9-24.
• the Cpfl or Cpf 1 mutant protein comprises the amino acid sequence of any one of SEQ ID NOs: 9-24.
• the nucleic acid programmable DNA binding protein [0011] In some embodiments, the nucleic acid programmable DNA binding protein
• napDNAbp is a C2cl protein.
• the C2cl protein comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 26. In some embodiments, the C2cl protein comprises the amino acid sequence of SEQ ID NO: 26.
• the nucleic acid programmable DNA binding protein [0012] In some embodiments, the nucleic acid programmable DNA binding protein
• napDNAbp is a C2c2 protein.
• the C2c2 protein comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 27. In some embodiments, the C2c2 protein comprises the amino acid sequence of SEQ ID NO: 27.
• the nucleic acid programmable DNA binding protein [0013] In some embodiments, the nucleic acid programmable DNA binding protein
• napDNAbp is a C2c3 protein.
• the C2c3 protein comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 28. In some embodiments, the C2c3 protein comprises the amino acid sequence of SEQ ID NO: 28.
• the nucleic acid programmable DNA binding protein [0014] In some embodiments, the nucleic acid programmable DNA binding protein
• napDNAbp is an Argonaute protein.
• the Argonaute protein comprises an amino acid sequence that is at least 90% identical to SEQ ID NO: 25. In some embodiments, the Argonaute protein comprises the amino acid sequence of SEQ ID NO: 25.
• fusion proteins provided herein are capable of generating one or more mutations (e.g., a C to T mutation) without generating a large proportion of indels.
• any of the fusion proteins (e.g., base editing proteins) provided herein generate less than 10% indels.
• any of the fusion proteins (e.g., base editing proteins) provided herein generate less than 10%, 9%, 8%, 7%, 6%, 5.5%, 5%, 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, 0.5%, or 0.1% indels.
• the fusion protein comprises a napDNAbp and an
• apolipoprotein B mRNA-editing complex 1 (APOBEC l) deaminase domain, where the deaminase domain is fused to the N-terminus of the napDNAbp domain via a linker comprising the amino acid sequence SGSETPGTSESATPES (SEQ ID NO: 604).
• the napDNAbp comprises the amino acid sequence of any of the napDNAbp provided herein.
• the deaminase is rat APOBECl (SEQ ID NO: 76).
• the deaminase is human APOBEC l (SEQ ID NO: 74).
• the deaminase is pmCDAl (SEQ ID NO: 81). In some embodiments, the deaminase is human APOBEC3G (SEQ ID NO: 60). In some embodiments, the deaminase is a human APOBEC3G variant of any one of (SEQ ID NOs: 82-84).
• the fusion protein comprises a napDNAbp and an apolipoprotein B mRNA-editing complex 1 catalytic polypeptide-like 3G (APOBEC3G) deaminase domain, wherein the deaminase domain is fused to the N-terminus of the napDNAbp domain via a linker of any length or composition (e.g., an amino acid sequence, a peptide, a polymer, or a bond).
• the linker comprises the amino acid sequence SGSETPGTSESATPES (SEQ ID NO: 604).
• the linker comprises the amino acid sequence
• SGGSSGGSSGS ETPGTS ES ATPES SGGSSGGS (SEQ ID NO: 605).
• the fusion protein comprises a napDNAbp and a cytidine deaminase 1 (CDA1) deaminase domain, wherein the deaminase domain is fused to the N- terminus of the napDNAbp domain via a linker comprising the amino acid sequence
• the linker comprises the amino acid sequence SGGSSGGSSGS ETPGTS ES ATPES SGGSSGGS (SEQ ID NO: 605).
• the napDNAbp comprises the amino acid sequence of any of the napDNAbp s provided herein.
• the fusion protein comprises a napDNAbp and an activation- induced cytidine deaminase (AID) deaminase domain, where the deaminase domain is fused to the N-terminus of the napDNAbp domain via a linker comprising the amino acid sequence SGSETPGTSESATPES (SEQ ID NO: 604).
• the linker comprises the amino acid sequence SGGSSGGSSGS ETPGTS ES ATPES SGGSSGGS (SEQ ID NO: 605).
• the napDNAbp comprises the amino acid sequence of any of the napDNAbp s provided herein.
• a nucleobase editing fusion protein with an apolipoprotein B mRNA- editing complex 1 (APOBEC1) deaminase domain fused to the N-terminus of a napDNAbp via a linker comprising the amino acid sequence SGSETPGTSESATPES (SEQ ID NO: 604) was capable of efficiently deaminating target nucleic acids in a double stranded DNA target molecule.
• the fusion protein comprises a napDNAbp domain and an apolipoprotein B mRNA-editing complex 1 (APOBEC1) deaminase domain, where the deaminase domain is fused to the N-terminus of the napDNAbp via a linker comprising the amino acid sequence SGSETPGTSESATPES (SEQ ID NO: 604).
• APOBEC1 apolipoprotein B mRNA-editing complex 1
• Some aspects of this disclosure provide strategies, systems, reagents, methods, and kits that are useful for the targeted editing of nucleic acids, including editing a single site within a subject' s genome, e.g., a human' s genome.
• fusion proteins of napDNAbp e.g., CasX, CasY, Cpfl, C2cl, C2c2, C2c3, or Argonaute protein
• deaminases or deaminase domains are provided.
• methods for targeted nucleic acid editing are provided.
• reagents and kits for the generation of targeted nucleic acid editing proteins e.g., fusion proteins of napDNAbp and deaminases or deaminase domains, are provided.
• fusion proteins comprising a napDNAbp as provided herein that is fused to a second protein (e.g., an enzymatic domain such as a cytidine deaminase domain), thus forming a fusion protein.
• a second protein e.g., an enzymatic domain such as a cytidine deaminase domain
• the second protein comprises an enzymatic domain, or a binding domain.
• the enzymatic domain is a nuclease, a nickase, a recombinase, a deaminase, a methyltransferase, a methylase, an acetylase, an acetyltransferase, a transcriptional activator, or a transcriptional repressor domain.
• the enzymatic domain is a nucleic acid editing domain.
• the nucleic acid editing domain is a deaminase domain.
• the deaminase is a cytosine deaminase or a cytidine deaminase.
• the deaminase is an apolipoprotein B mRNA-editing complex (APOBEC) family deaminase. In some embodiments, the deaminase is an APOBEC 1 deaminase. In some embodiments, the deaminase is an APOBEC2 deaminase. In some embodiments, the deaminase is an APOBEC3 deaminase. In some embodiments, the deaminase is an APOBEC 1 deaminase. In some embodiments, the deaminase is an APOBEC2 deaminase. In some embodiments, the deaminase is an APOBEC3 deaminase. In some embodiments, the deaminase is an APOBEC1 deaminase. In some embodiments, the deaminase is an APOBEC 1 deaminase. In some embodiments, the deamina
• the deaminase is an APOBEC3A deaminase. In some embodiments, the deaminase is an APOBEC3B deaminase. In some embodiments, the deaminase is an APOBEC3C deaminase. In some embodiments, the deaminase is an APOBEC3D deaminase. In some embodiments, the deaminase is an
• the deaminase is an APOBEC3F deaminase. In some embodiments, the deaminase is an APOBEC3G deaminase. In some embodiments, the deaminase is an APOBEC3H deaminase. In some embodiments, the deaminase is an APOBEC4 deaminase. In some embodiments, the deaminase is an activation-induced deaminase (AID). It should be appreciated that the deaminase may be from any suitable organism (e.g. , a human or a rat).
• the deaminase is from a human, chimpanzee, gorilla, monkey, cow, dog, rat, or mouse. In some embodiments, the deaminase is rat APOBEC 1 (SEQ ID NO: 76). In some embodiments, the deaminase is human
• APOBEC 1 (SEQ ID NO: 74).
• the deaminase is pmCDAl .
• Some aspects of this disclosure provide fusion proteins comprising: (i) a CasX, CasY, Cpfl, C2cl, C2c2, C2c3, or Argonaute protein domain comprising the amino acid sequence of SEQ ID NO: 32; and (ii) an apolipoprotein B mRNA-editing complex 1
• APOBEC1 deaminase domain, wherein the deaminase domain is fused to the N-terminus of the napDNAbp via a linker comprising the amino acid sequence of SGSETPGTSESATPES (SEQ ID NO: 604).
• the deaminase is rat APOBEC 1 (SEQ ID NO: 76).
• the deaminase is human APOBEC1 (SEQ ID NO: 74).
• the fusion protein comprises the amino acid sequence of SEQ ID NO: 591.
• the fusion protein comprises the amino acid sequence of SEQ ID NO: 5737.
• the deaminase is pmCDAl (SEQ ID NO: 81). In some embodiments, the deaminase is human APOBEC3G (SEQ ID NO: 60). In some embodiments, the deaminase is a human APOBEC3G variant of any one of SEQ ID NOs: 82-84.
• fusion proteins comprising a deaminase domain, a napDNAbp domain and a uracil glycosylase inhibitor (UGI) domain demonstrate improved efficiency for deaminating target nucleotides in a nucleic acid molecule.
• U:G heteroduplex DNA may be responsible for a decrease in nucleobase editing efficiency in cells.
• Uracil DNA glycosylase (UDG) catalyzes removal of U from DNA in cells, which may initiate base excision repair, with reversion of the U:G pair to a C:G pair as the most common outcome.
• Uracil DNA Glycosylase Inhibitor may inhibit human UDG activity.
• base excision repair may be inhibited by molecules that bind the single strand, block the edited base, inhibit UGI, inhibit base excision repair, protect the edited base, and/or promote "fixing" of the non-edited strand, etc.
• this disclosure contemplates fusion proteins comprising a napDNAbp-cytidine deaminase domain that is fused to a UGI domain.
• fusion proteins comprising a deaminase domain, a napDNAbp domain, and more than one uracil glycosylase inhibitor (UGI) domain (e.g., one, two, three, four, five, or more UGI domains) demonstrate improved efficiency for deaminating target nucleotides in a nucleic acid molecule and/or improved nucleic acid product purity.
• UGI uracil glycosylase inhibitor
• the addition of a second UGI domain may substantially decrease the access of UDG to the G:U base editing intermediate, thereby improving the efficiency of the base editing.
• any of the base editors provided herein are capable of modifying a specific nucleotide base without generating a significant proportion of indels.
• An "indel", as used herein, refers to the insertion or deletion of a nucleotide base within a nucleic acid. Such insertions or deletions can lead to frame shift mutations within a coding region of a gene.
• any of the base editors provided herein are capable of generating a greater proportion of intended modifications (e.g., point mutations or deaminations) versus indels.
• any of the base editors provided herein are capable of generating a certain percentage of desired mutations.
• the desired mutation is a C to T mutation.
• the desired mutation is a C to A mutation,
• the desired mutation is a C to G mutation.
• any of the base editors provided herein are capable of generating at least 1% of desired mutations.
• any of the base editors provided herein are capable of generating at least 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, 95%, or 99% of desired mutations.
• Some aspects of the disclosure are based on the recognition that any of the base editors provided herein are capable of efficiently generating an intended mutation, such as a point mutation, in a nucleic acid (e.g. a nucleic acid within a genome of a subject) without generating a significant number of unintended mutations, such as unintended point mutations.
• an intended mutation such as a point mutation
• the deaminase domain of the fusion protein is fused to the N- terminus of the napDNAbp domain.
• the UGI domain is fused to the C- terminus of the napDNAbp domain.
• the napDNAbp and the nucleic acid editing domain are fused via a linker.
• the napDNAbp domain and the UGI domain are fused via a linker.
• a second UGI domain is fused to the C-terminus of a first UGI domain.
• the first UGI domain and the second UGI domain are fused via a linker.
• linkers may be used to link any of the peptides or peptide domains of the invention.
• the linker may be as simple as a covalent bond, or it may be a polymeric linker many atoms in length.
• the linker is a polpeptide or based on amino acids. In other embodiments, the linker is not peptide-like.
• the linker is a covalent bond (e.g., a carbon-carbon bond, disulfide bond, carbon-heteroatom bond, etc.).
• the linker is a carbon-nitrogen bond of an amide linkage.
• the linker is a cyclic or acyclic, substituted or unsubstituted, branched or unbranched aliphatic or hetero aliphatic linker.
• the linker is polymeric (e.g., polyethylene, polyethylene glycol, polyamide, polyester, etc.).
• the linker comprises a monomer, dimer, or polymer of aminoalkanoic acid.
• the linker comprises an aminoalkanoic acid (e.g., glycine, ethanoic acid, alanine, beta-alanine, 3-aminopropanoic acid, 4-aminobutanoic acid, 5-pentanoic acid, etc.).
• the linker comprises a monomer, dimer, or polymer of aminohexanoic acid (Ahx). In certain embodiments, the linker is based on a carbocyclic moiety (e.g., cyclopentane, cyclohexane). In other embodiments, the linker comprises a polyethylene glycol moiety (PEG). In other embodiments, the linker comprises amino acids. In certain embodiments, the linker comprises a peptide. In certain embodiments, the linker comprises an aryl or heteroaryl moiety. In certain embodiments, the linker is based on a phenyl ring. The linker may included funtionalized moieties to facilitate attachment of a nucleophile (e.g.
• electrophile Any electrophile may be used as part of the linker.
• exemplary electrophiles include, but are not limited to, activated esters, activated amides, Michael acceptors, alkyl halides, aryl halides, acyl halides, and
• the linker comprises the amino acid sequence (GGGGS) n (SEQ ID NO: 607), (G) substitution (SEQ ID NO: 608), (EAAAK) context (SEQ ID NO: 609), (GGS) connect (SEQ ID NO:610), (SGGS) connect (SEQ ID NO: 606), SGSETPGTSESATPES (SEQ ID NO: 604), (XP) thread (SEQ ID NO: 611), SGGS(GGS) n (SEQ ID NO: 612),
• the linker comprises the amino acid sequence (GGS) n (SEQ ID NO: 610), wherein n is 1, 3, or 7. In some embodiments, the linker comprises the amino acid sequence SGGS(GGS) n (SEQ ID NO: 612), wherein n is 2. In some embodiments, the linker comprises the amino acid sequence SGSETPGTSESATPES (SEQ ID NO: 604). In some embodiments, the linker comprises the amino acid sequence
• SGGSSGGSSGS ETPGTS ES ATPES SGGSSGGS (SEQ ID NO: 605).
• the fusion protein comprises the structure [nucleic acid editing domain] -[optional linker sequence] -[napDNAbp]- [optional linker sequence] -[UGI] .
• the fusion protein comprises the structure [nucleic acid editing domain] - [optional linker sequence] -[UGI] -[optional linker sequence] -[napDNAbp] ; [UGI] -[optional linker sequence] -[nucleic acid editing domain] -[optional linker sequence] -[napDNAbp];
• the nucleic acid editing domain comprises a deaminase. In some embodiments, the nucleic acid editing domain comprises a deaminase. In some embodiments, the deaminase is a cytidine deaminase. In some embodiments, the deaminase is an apolipoprotein B mRNA-editing complex (APOBEC) family deaminase.
• APOBEC apolipoprotein B mRNA-editing complex
• the deaminase is an APOBEC 1 deaminase, an APOBEC2 deaminase, an APOBEC3A deaminase, an APOBEC3B deaminase, an APOBEC3C deaminase, an
• APOBEC3D deaminase an APOBEC3D deaminase
• an APOBEC3F deaminase an APOBEC3G deaminase
• an APOBEC3D deaminase an APOBEC3D deaminase
• an APOBEC3F deaminase an APOBEC3F deaminase
• an APOBEC3G deaminase an APOBEC3G deaminase
• the deaminase is an activation-induced deaminase (AID).
• the deaminase is a cytidine deaminase 1 (CDA1).
• the deaminase is a Lamprey CDA1 (pmCDAl) deaminase.
• the deaminase is from a human, chimpanzee, gorilla, monkey, cow, dog, rat, or mouse. In some embodiments, the deaminase is from a human. In some embodiments the deaminase is from a rat. In some embodiments, the deaminase is a rat APOBEC 1 deaminase comprising the amino acid sequence set forth in (SEQ ID NO: 76). In some embodiments, the deaminase is a human APOBEC 1 deaminase comprising the amino acid sequence set forth in (SEQ ID NO: 74).
• the deaminase is pmCDAl (SEQ ID NO: 81). In some embodiments, the deaminase is human APOBEC 3 G (SEQ ID NO: 60). In some embodiments, the deaminase is a human APOBEC3G variant of any one of (SEQ ID NOs: 82-84). In some embodiments, the deaminase is at least 80%, at least 85%, at least 90%, at least 92%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.5% identical to any one of the amino acid sequences set forth in SEQ ID NOs: 49-84.
• the UGI domain comprises an amino acid sequence that is at least 80%, at least 85%, at least 90%, at least 92%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.5% identical to SEQ ID NO: 134. In some embodiments, the UGI domain comprises the amino acid sequence as set forth in SEQ ID NO: 134.
• Some aspects of this disclosure provide complexes comprising a napDNAbp fusion protein as provided herein, and a guide RNA bound to the napDNAbp.
• Some aspects of this disclosure provide methods of using the napDNAbp, fusion proteins, or complexes provided herein. For example, some aspects of this disclosure provide methods comprising contacting a DNA molecule (a) with a napDNAbp or a fusion protein as provided herein and with a guide RNA, wherein the guide RNA is about 15- 100 nucleotides long and comprises a sequence of at least 10 contiguous nucleotides that is complementary to a target sequence; or (b) with a napDNAbp, a napDNAbp fusion protein, or a napDNAbp or napDNAbp complex with a gRNA as provided herein.
• kits comprising a nucleic acid construct, comprising (a) a nucleotide sequence encoding a napDNAbp or a napDNAbp fusion protein as provided herein; and (b) a heterologous promoter that drives expression of the sequence of (a).
• the kit further comprises an expression construct encoding a guide RNA backbone, wherein the construct comprises a cloning site positioned to allow the cloning of a nucleic acid sequence identical or complementary to a target sequence into the guide RNA backbone.
• Some aspects of this disclosure provide polynucleotides encoding a napDNAbp of a fusion protein as provided herein. Some aspects of this disclosure provide vectors comprising such polynucleotides. In some embodiments, the vector comprises a heterologous promoter driving expression of polynucleotide.
• Some aspects of this disclosure provide cells comprising a napDNAbp protein, a fusion protein, a nucleic acid molecule, and/or a vector as provided herein.
• any of the fusion proteins provided herein that include a Cas9 domain may be replaced with any of the napDNAbp provided herein, for example CasX, CasY, Cpfl, C2cl, C2c2, C2c3, or Argonaute protein.
• Figure 1 shows the deaminase activity of deaminases on single stranded DNA substrates.
• Single stranded DNA substrates using randomized PAM sequences (NNN PAM) were used as negative controls.
• Canonical PAM sequences used include the (NGG PAM).
• Figure 2 shows the activity of Cas9:deaminase fusion proteins on single stranded DNA substrates.
• Figure 3 illustrates double stranded DNA substrate binding by
• Figure 4 illustrates a double stranded DNA deamination assay.
• Figure 5 demonstrates that Cas9 fusions can target positions 3-11 of double-stranded DNA target sequences (numbered according to the schematic in Figure 5).
• Upper Gel 1 ⁇ rAPOBECl-GGS-dCas9, 125 nM dsDNA, 1 equivalent sgRNA.
• Mid Gel 1 ⁇ rAPOBECl- (GGS) 3 (SEQ ID NO: 610)-dCas9, 125 nM dsDNA, 1 equivalent sgRNA.
• Lower Gel 1.85 ⁇ rAPOBECl-XTEN-dCas9, 125 nM dsDNA, 1 equivalent sgRNA.
• Figure 6 demonstrates that the correct guide RNA, e.g., the correct sgRNA, is required for deaminase activity.
• Figure 7 illustrates the mechanism of target DNA binding of in vivo target sequences by deaminase-dCas9:sgRNA complexes.
• Figure 8 shows successful deamination of exemplary disease-associated target sequences.
• Figure 9 shows in vitro C ⁇ T editing efficiencies using His6-rAPOBECl-XTEN- dCas9.
• Figure 10 shows C ⁇ T editing efficiencies in HEK293T cells is greatly enhanced by fusion with UGI.
• Figures 11A to 11C show NBE1 mediates specific, guide RNA-programmed C to U conversion in vitro.
• Figure 11 A Nucleobase editing strategy. DNA with a target C at a locus specified by a guide RNA is bound by dCas9, which mediates the local denaturation of the DNA substrate. Cytidine deamination by a tethered APOBEC1 enzyme converts the target C to U. The resulting G:U heteroduplex can be permanently converted to an A:T base pair following DNA replication or repair. If the U is in the template DNA strand, it will also result in an RNA transcript containing a G to A mutation following transcription.
• Figure 1 IB Deamination assay showing an activity window of approximately five nucleotides. Following incubation of NBEl-sgRNA complexes with dsDNA substrates at 37 °C for 2 h, the 5' fluorophore-labeled DNA was isolated and incubated with USER enzyme (uracil DNA glycosylase and endonuclease VIII) at 37 °C for 1 h to induce DNA cleavage at the site of any uracils. The resulting DNA was resolved on a denaturing polyacrylamide gel, and any fluorophore-linked strands were visualized.
• USER enzyme uracil DNA glycosylase and endonuclease VIII
• Each lane is labeled according to the position of the target C within the protospacer, or with "-" if no target C is present, counting the base distal from the PAM as position 1.
• Figure 11C Deaminase assay showing the sequence specificity and sgRNA-dependence of NBE1.
• the DNA substrate with a target C at position 7 was incubated with NBE1 as in Figure 1 IB with either the correct sgRNA, a mismatched sgRNA, or no sgRNA. No C to U editing is observed with the mismatched sgRNA or with no sgRNA.
• the positive control sample contains a DNA sequence with a U synthetically incorporated at position 7.
• Figures 12A to 12B show effects of sequence context and target C position on nucleobase editing efficiency in vitro.
• Figure 12A Effect of changing the sequence surrounding the target C on editing efficiency in vitro.
• the deamination yield of 80% of targeted strands (40% of total sequencing reads from both strands) for C 7 in the protospacer sequence 5'-TTATTTCGTGGATTTATTTA-3'(SEQ ID NO: 591) was defined as 1.0, and the relative deamination efficiencies of substrates containing all possible single-base mutations at positions 1-6 and 8-13 are shown. Values and error bars reflect the mean and standard deviation of two or more independent biological replicates performed on different days.
• Figure 12B Positional effect of each NC motif on editing efficiency in vitro.
• NC target motif was varied from positions 1 to 8 within the protospacer as indicated in the sequences shown on the right (the PAM shown in red, the protospacer plus one base 5' to the protospacer are also shown).
• the percentage of total sequence reads containing T at each of the numbered target C positions following incubation with NBE1 is shown in the graph. Note that the maximum possible deamination yield in vitro is 50% of total sequencing reads (100% of targeted strands). Values and error bars reflect the mean and standard deviation of two or three independent biological replicates performed on different days.
• Figure 12B depicts SEQ ID NOs: 619 through 626from top to bottom, respectively.
• Figures 13A to 13C show nucleobase editing in human cells.
• Figure 13 A shows nucleobase editing in human cells.
• FIG. 13A depicts SEQ ID NOs: 127 through 132 from top to bottom, respectively.
• Figure 13B HEK293T cells were transfected with plasmids expressing NBE1, NBE2, or NBE3 and an appropriate sgRNA. Three days after transfection, genomic DNA was extracted and analyzed by high-throughput DNA sequencing at the six loci.
• Cellular C to T conversion percentages defined as the percentage of total DNA sequencing reads with Ts at the target positions indicated, are shown for NBE1, NBE2, and NBE3 at all six genomic loci, and for wt Cas9 with a donor HDR template at three of the six sites (EMX1, HEK293 site 3, and HEK293 site 4). Values and error bars reflect the mean and standard deviation of three independent biological replicates performed on different days.
• Figure 13C Frequency of indel formation, calculated as described in the Methods, is shown following treatment of HEK293T cells with NBE2 and NBE3 for all six genomic loci, or with wt Cas9 and a single- stranded DNA template for HDR at three of the six sites (EMX1, HEK293 site 3, and HEK293 site 4). Values reflect the mean of at least three independent biological replicates performed on different days.
• Figures 14A to 14C show NBE2- and NBE3-mediated correction of three disease- relevant mutations in mammalian cells.
• sequence of the protospacer is indicated to the right of the name of the mutation, with the PAM and the base responsible for the mutation indicated in bold with a subscripted number corresponding to its position within the protospacer.
• the amino acid sequence above each disease-associated allele is shown, together with the corrected amino acid sequence following nucleobase editing in red.
• FIG. 14A The Alzheimer's disease- associated APOE4 allele is converted to APOE3 ' in mouse astrocytes by NBE3 in 11% of total reads (44% of nucleofected astrocytes). Two nearby Cs are also converted to Ts, but with no change to the predicted sequence of the resulting protein (SEQ ID NO: 627).
• Figure 14B The cancer-associated p53 N239D mutation is corrected by NBE2 in 11% of treated human lymphoma cells (12% of nucleofected cells) that are heterozygous for the mutation (SEQ ID NO: 628).
• Figure 14C The p53 Y163C mutation is corrected by NBE3 in 7.6% of nucleofected human breast cancer cells (SEQ ID NO: 629).
• Figures 15A to 15D show effects of deaminase-dCas9 linker length and composition on nucleobase editing.
• Gel-based deaminase assay showing the deamination window of nucleobase editors with deaminase-Cas9 linkers of GGS ( Figure 15A), (GGS (SEQ ID NO: 610) ( Figure 15B), XTEN ( Figure 15C), or (GGS) 7 (SEQ ID NO: 610) ( Figure 15D).
• Figures 16A to 16B show NBE1 is capable of correcting disease-relevant mutations in vitro.
• Figure 16A Protospacer and PAM sequences of seven disease-relevant mutations.
• the disease-associated target C in each case is indicated with a subscripted number reflecting its position within the protospacer. For all mutations except both APOE4 SNPs, the target C resides in the template (non-coding) strand.
• Figure 16A depicts SEQ ID NOs: 631 through 636 from top to bottom, respectively.
• Figure 16B Deaminase assay showing each dsDNA oligonucleotide before ( -) and after (+) incubation with NBE1, DNA isolation, and incubation with USER enzymes to cleave DNA at positions containing U. Positive control lanes from incubation of synthetic oligonucleotides containing U at various positions within the protospacer with USER enzymes are shown with the corresponding number indicating the position of the U.
• Figure 17 shows processivity of NBE1.
• the protospacer and PAM of a 60-mer DNA oligonucleotide containing eight consecutive Cs is shown at the top.
• the oligonucleotide (125 iiM ) was incubated with NBE1 (2 ⁇ ) for 2 h at 37 °C.
• the DNA was isolated and analyzed by high-throughput sequencing. Shown are the percent of total reads for the most frequent nine sequences observed. The vast majority of edited strands (>93%) have more than one C converted to T.
• This figure depicts SEQ ID NO: 309.
• Figures 18A to 18H show the effect of fusing UGI to NBEl to generate NBE2.
• Figure 18 A Protospacer and PAM sequences of the six mammalian cell genomic loci targeted with nucleobase editors. Editable Cs are indicated with labels corresponding to their positions within the protospacer.
• Figure 18A depicts SEQ ID NOs: 127 through 132 from top to bottom, respectively.
• Figures 18B to 18G HEK293T cells were transfected with plasmids expressing NBEl, NBE2, or NBEl and UGI, and an appropriate sgRNA. Three days after transfection, genomic DNA was extracted and analyzed by high-throughput DNA sequencing at the six loci.
• Cellular C to T conversion percentages defined as the percentage of total DNA sequencing reads with Ts at the target positions indicated, are shown for NBEl, NBEl and UGI, and NBE2 at all six genomic loci.
• Figure 18H C to T mutation rates at 510 Cs surrounding the protospacers of interest for NBEl, NBEl plus UGI on a separate plasmid, NBE2. and untreated cells are shown.
• the data show the results of 3,000,000 DNA sequencing reads from 1.5x106 cells. Values reflect the mean of at least two biological experiments conducted on different days.
• Figure 19 shows nucleobase editing efficiencies of NBE2 in U20S and HEK293T cells.
• Cellular C to T conversion percentages by NBE2 are shown for each of the six targeted genomic loci in HEK293T cells and U20S cells.
• HEK293T cells were transfected using lipofectamine 2000, and U20S cells were nucleofected.
• U20S nucleofection efficiency was 74%.
• Figure 20 shows nucleobase editing persists over multiple cell divisions.
• Cellular C to T conversion percentages by NBE2 are displayed at two genomic loci in HEK293T cells before and after passaging the cells.
• HEK293T cells were transfected using Lipofectamine 2000. Three days post transfection, the cells were harvested and split in half. One half was subjected to HTS analysis, and the other half was allowed to propagate for approximately five cell divisions, then harvested and subjected to HTS analysis.
• Figure 21 shows genetic variants from ClinVar that can be corrected in principle by nucleobase editing.
• NCBI ClinVar database of human genetic variations and their corresponding phenotypes 68 was searched for genetic diseases that can be corrected by current nucleobase editing technologies.
• the results were filtered by imposing the successive restrictions listed on the left.
• the x-axis shows the number of occurrences satisfying that restriction and all above restrictions on a logarithmic scale.
• Figure 22 shows in vitro identification of editable Cs in six genomic loci. Synthetic 80-mers with sequences matching six different genomic sites were incubated with NBEl then analyzed for nucleobase editing via HTS. For each site, the sequence of the protospacer is indicated to the right of the name of the site, with the PAM highlighted in red. Underneath each sequence are the percentages of total DNA sequencing reads with the corresponding base. A target C was considered as "editable” if the in vitro conversion efficiency is >10%. Note that maximum yields are 50% of total DNA sequencing reads since the non-targeted strand is not a substrate for nucleobase editing. This figure depicts SEQ ID NOs: 127 through 132 from top to bottom, respectively.
• Figure 23 shows activities of NBEl, NBE2, and NBE3 at EMX1 off-targets.
• HEK293T cells were transfected with plasmids expressing NBEl, NBE2, or NBE3 and a sgRNA matching the EMX1 sequence using Lipofectamine 2000.
• genomic DNA was extracted, amplified by PCR, and analyzed by high- throughput DNA sequencing at the on-target loci, plus the top ten known Cas9 off-target loci for the EMX1 sgRNA, as previously determined using the GUIDE-seq method 55 .
• EMX1 off- target 5 locus did not amplify and is not shown. Sequences of the on-target and off-target protospacers and protospacer adjacent motifs (PAMs) are displayed.
• conversion percentages defined as the percentage of total DNA sequencing reads with T at each position of an original C within the protospacer, are shown for NBE1, NBE2, and NBE3. On the far right are displayed the total number of sequencing reads reported for each sequence. This figure depicts SEQ ID NOs: 127, and 637 through 645 from top to bottom, respectively.
• Figure 24 shows activities of NBE1, NBE2, and NBE3 at FANCF off-targets.
• HEK293T cells were transfected with plasmids expressing NBE1, NBE2, or NBE3 and a sgRNA matching the FANCF sequence using Lipofectamine 2000.
• genomic DNA was extracted, amplified by PCR, and analyzed by high- throughput DNA sequencing at the on-target loci, plus all of the known Cas9 off-target loci for the FANCF sgRNA, as previously determined using the GUIDE-seq method 55 . Sequences of the on-target and off-target protospacers and protospacer adjacent motifs (PAMs) are displayed.
• Cellular C to T conversion percentages defined as the percentage of total DNA sequencing reads with T at each position of an original C within the protospacer, are shown for NBE1, NBE2, and NBE3. On the far right are displayed the total number of sequencing reads reported for each sequence. This figure depicts SEQ ID NOs: 128 and 646 through 653 from top to bottom, respectively.
• Figure 25 shows activities of NBE1, NBE2, and NBE3 at HEK293 site 2 off-targets.
• HEK293T cells were transfected with plasmids expressing NBE1, NBE2, or NBE3 and a sgRNA matching the HEK293 site 2 sequence using Lipofectamine 2000.
• genomic DNA was extracted, amplified by PCR, and analyzed by high- throughput DNA sequencing at the on-target loci, plus all of the known Cas9 off-target loci for the HEK293 site 2 sgRNA, as previously determined using the GUIDE-seq method 55 .
• HEK293T cells were transfected with plasmids expressing NBE1, NBE2, or NBE3 and a sgRNA matching the HEK293 site 3 sequence using Lipofectamine 2000. Three days after transfection, genomic DNA was extracted, amplified by PCR, and analyzed by high- throughput DNA sequencing at the on-target loci, plus all of the known Cas9 off-target loci for the HEK293 site 3 sgRNA, as previously determined using the GUIDE-seq method. 55
• Figure 27 shows activities of NBE1, NBE2, and NBE3 at HEK293 site 4 off-targets.
• HEK293T cells were transfected with plasmids expressing NBE1, NBE2, or NBE3 and a sgRNA matching the HEK293 site 4 sequence using Lipofectamine 2000.
• genomic DNA was extracted, amplified by PCR, and analyzed by high- throughput DNA sequencing at the on-target loci, plus the top ten known Cas9 off-target loci for the HEK293 site 4 sgRNA, as previously determined using the GUIDE-seq method.
• Figure 28 shows non-target C mutation rates. Shown here are the C to T mutation rates at 2,500 distinct cytosines surrounding the six on-target and 34 off-target loci tested, representing a total of 14,700,000 sequence reads derived from approximately 1.8x106 cells.
• Figures 29A to 29C show base editing in human cells.
• Figure 29A shows possible base editing outcomes in mammalian cells. Initial editing resulted in a U:G mismatch.
• UDG uracil DNA glycosylase
• Figures 30A to 30B show BE3-mediated correction of two disease-relevant mutations in mammalian cells.
• the sequence of the protospacer is shown to the right of the mutation, with the PAM and the target base in red with a subscripted number indicating its position within the protospacer. Underneath each sequence are the percentages of total sequencing reads with the corresponding base.
• Cells were treated as described in the Materials and Methods.
• Figure 30A shows the Alzheimer's disease-associated APOE4 allele converted to APOE3r in mouse astrocytes by BE3 in 74.9% of total reads. Two nearby Cs were also converted to Ts, but with no change to the predicted sequence of the resulting protein.
• Figure 31 shows activities of BE1, BE2, and BE3 at HEK293 site 2 off-targets.
• HEK293T cells were transfected with plasmids expressing BE1, BE2, or BE3 and a sgRNA matching the HEK293 site 2 sequence using Lipofectamine 2000. Three days after
• genomic DNA was extracted, amplified by PCR, and analyzed by high- throughput DNA sequencing at the on-target loci, plus all of the known Cas9 and dCas9 off- target loci for the HEK293 site 2 sgRNA, as previously determined by Joung and coworkers using the GUIDE-seq method (63), and Adli and coworkers using chromatin
• ChlP-seq immunoprecipitation high-throughput sequencing
• Figure 32 shows activities of BEl, BE2, and BE3 at HEK293 site 3 off-targets.
• HEK293T cells were transfected with plasmids expressing BEl, BE2, or BE3 and a sgRNA matching the HEK293 site 3 sequence using Lipofectamine 2000. Three days after
• genomic DNA was extracted, amplified by PCR, and analyzed by high- throughput DNA sequencing at the on-target loci, plus all of the known Cas9 off-target loci and the top five known dCas9 off-target loci for the HEK293 site 3 sgRNA, as previously determined by Joung and coworkers using the GUIDE-seq method 54 , and using chromatin immunoprecipitation high-throughput sequencing (ChlP-seq) experiments 61 . Sequences of the on-target and off-target protospacers and protospacer adjacent motifs (PAMs) are displayed.
• PAMs protospacer adjacent motifs
• Cellular C to T conversion percentages defined as the percentage of total DNA sequencing reads with T at each position of an original C within the protospacer, are shown for BEl, BE2, and BE3. On the far right are displayed the total number of sequencing reads reported, and the ChlP-seq signal intensity reported for each sequence. This figure depicts SEQ ID NOs: 130, 656 to 660 and 678-682 from top to bottom, respectively.
• Figure 33 shows activities of BEl, BE2, and BE3 at HEK293 site 4 off-targets.
• HEK293T cells were transfected with plasmids expressing BEl, BE2, or BE3 and a sgRNA matching the HEK293 site 4 sequence using Lipofectamine 2000. Three days after
• genomic DNA was extracted, amplified by PCR, and analyzed by high- throughput DNA sequencing at the on-target loci, plus the top ten known Cas9 off-target loci and the top five known dCas9 off-target loci for the HEK293 site 4 sgRNA, as previously determined using the GUIDE-seq method 54 , and using chromatin immunoprecipitation high- throughput sequencing (ChlP-seq) experiments 61 . Sequences of the on-target and off-target protospacers and protospacer adjacent motifs (PAMs) are displayed.
• PAMs protospacer adjacent motifs
• Cellular C to T conversion percentages defined as the percentage of total DNA sequencing reads with T at each position of an original C within the protospacer, are shown for BEl, BE2, and BE3. On the far right are displayed the total number of sequencing reads reported, and the ChlP-seq signal intensity reported for each sequence. This figure depicts SEQ ID NOs: 131, 661 to 670, 683 and 684 from top to bottom, respectively.
• Figure 34 shows mutation rates of non-protospacer bases following BE3-mediated correction of the Alzheimer's disease-associated APOE4 allele to APOE3r in mouse astrocytes.
• the DNA sequence of the 50 bases on either side of the protospacer from Figure 30A and Figure 34B is shown with each base's position relative to the protospacer.
• the side of the protospacer distal to the PAM is designated with positive numbers, while the side that includes the PAM is designated with negative numbers, with the PAM.
• each sequence are the percentages of total DNA sequencing reads with the corresponding base for untreated cells, for cells treated with BE3 and an sgRNA targeting the APOE4 C158R mutation, or for cells treated with BE3 and an sgRNA targeting the VEGFA locus.
• BE3-treated sample resulted in mutation rates above those of untreated controls.
• This figure depicts SEQ ID NOs: 685 to 688 from top to bottom, respectively.
• Figure 35 shows mutation rates of non-protospacer bases following BE3-mediated correction of the cancer-associated p53 Y163C mutation in HCC1954 human cells.
• the DNA sequence of the 50 bases on either side of the protospacer from Figure 30B and Figure 39B is shown with each base's position relative to the protospacer.
• the side of the protospacer distal to the PAM is designated with positive numbers, while the side that includes the PAM is designated with negative numbers, with the PAM.
• Underneath each sequence are the percentages of total sequencing reads with the corresponding base for untreated cells, for cells treated with BE3 and an sgRNA targeting the TP 53 Y163C mutation, or for cells treated with BE3 and an sgRNA targeting the VEGFA locus.
• Neither BE3-treated sample resulted in mutational rates above those of untreated controls.
• This figure depicts SEQ ID NOs: 689 to692 from top to bottom, respectively.
• Figures 36A to 36F show the effects of deaminase, linker length, and linker composition on base editing.
• Figure 36A shows a gel-based deaminase assay showing activity of rAPOBECl, pmCDAl, hAID, hAPOBEC3G, rAPOBECl-GGS-dCas9, rAPOBECl- (GGS) 3 (SEQ ID NO: 610)-dCas9, and dCas9-(GGS) 3 (SEQ ID NO: 610)-rAPOBECl on ssDNA.
• Enzymes were expressed in a mammalian cell lysate-derived in vitro transcription- translation system and incubated with 1.8 ⁇ dye-conjugated ssDNA and USER enzyme (uracil DNA glycosylase and endonuclease VIII) at 37 °C for 2 hours. The resulting DNA was resolved on a denaturing polyacrylamide gel and imaged.
• the positive control is a sequence with a U synthetically incorporated at the same position as the target C.
• Figure 36B shows coomassie-stained denaturing PAGE gel of the expressed and purified proteins used in Figures 36C to 36F.
• Figures 36C to 36F show gel-based deaminase assay showing the deamination window of base editors with deaminase-Cas9 linkers of GGS ( Figure 36C), (GGS) 3 (SEQ ID NO: 610) ( Figure 36D), XTEN ( Figure 36E), or (GGS) 7 (SEQ ID NO: 610) ( Figure 36F).
• Figures 37A to 37C show BEl base editing efficiencies are dramatically decreased in mammalian cells.
• Figure 37A Protospacer and PAM sequences of the six mammalian cell genomic loci targeted by base editors. Target Cs are indicated in red with subscripted numbers corresponding to their positions within the protospacer.
• Figure 37B shows synthetic 80-mers with sequences matching six different genomic sites were incubated with BEl then analyzed for base editing by HTS. For each site, the sequence of the protospacer is indicated to the right of the name of the site, with the PAM. Underneath each sequence are the percentages of total DNA sequencing reads with the corresponding base. We considered a target C as "editable" if the in vitro conversion efficiency is >10%.
• Figure 37C shows HEK293T cells were transfected with plasmids expressing BEl and an appropriate sgRNA. Three days after transfection, genomic DNA was extracted and analyzed by high-throughput DNA sequencing at the six loci. Cellular C to T conversion percentages, defined as the percentage of total DNA sequencing reads with Ts at the target positions indicated, are shown for BEl at all six genomic loci. Values and error bars of all data from HEK293T cells reflect the mean and standard deviation of three independent biological replicates performed on different days.
• Figure 37A depicts SEQ ID NOs: 127 to 132 from top to bottom, respectively.
• Figure 37B depicts SEQ ID NOs: 127 to 132 from top to bottom, respectively.
• Figure 38 shows base editing persists over multiple cell divisions.
• Cellular C to T conversion percentages by BE2 and BE3 are shown for HEK293 sites 3 and 4 in HEK293T cells before and after passaging the cells.
• HEK293T cells were nucleofected with plasmids expressing BE2 or BE3 and an sgRNA targeting HEK293 site 3 or 4.
• Three days after nucleofection, the cells were harvested and split in half. One half was subjected to HTS analysis, and the other half was allowed to propagate for approximately five cell divisions, then harvested and subjected to HTS analysis. Values and error bars reflect the mean and standard deviation of at least two biological experiments.
• Figures 39A to 39C show non-target C/G mutation rates. Shown here are the C to T and G to A mutation rates at 2,500 distinct cytosines and guanines surrounding the six on- target and 34 off-target loci tested, representing a total of 14,700,000 sequence reads derived from approximately 1.8xl0 6 cells.
• Figures 39A and 39B show cellular non-target C to T and G to A conversion percentages by BE1, BE2, and BE3 are plotted individually against their positions relative to a protospacer for all 2,500 cytosines/guanines. The side of the protospacer distal to the PAM is designated with positive numbers, while the side that includes the PAM is designated with negative numbers.
• Figure 39C shows average non-target cellular C to T and G to A conversion percentages by BE1, BE2, and BE3 are shown, as well as the highest and lowest individual conversion percentages.
• Figures 40A to 40B show additional data sets of BE3-mediated correction of two disease-relevant mutations in mammalian cells.
• sequence of the protospacer is indicated to the right of the name of the mutation, with the PAM and the base responsible for the mutation indicated in red bold with a subscripted number corresponding to its position within the protospacer.
• the amino acid sequence above each disease-associated allele is shown, together with the corrected amino acid sequence following base editing. Underneath each sequence are the percentages of total sequencing reads with the corresponding base.
• Cells were nucleofected with plasmids encoding BE3 and an appropriate sgRNA.
• Figure 40A shows the Alzheimer's disease- associated APOE4 allele is converted to APOE3r in mouse astrocytes by BE3 in 58.3% of total reads only when treated with the correct sgRNA. Two nearby Cs are also converted to Ts, but with no change to the predicted sequence of the resulting protein. Identical treatment of these cells with wt Cas9 and donor ssDNA results in 0.2% correction, with 26.7% indel formation.
• Figure 40B shows the cancer-associated p53 Y163C mutation is corrected by BE3 in 3.3% of nucleofected human breast cancer cells only when treated with the correct sgRNA. Identical treatment of these cells with wt Cas9 and donor ssDNA results in no detectable mutation correction with 8.0% indel formation.
• Figures 40A to 40B depict SEQ ID NOs: 671, 627, 672 and 629.
• Figure 41 shows a schematic representation of an exemplary USER (Uracil-Specific Excision Reagent) Enzyme-based assay, which may be used to test the activity of various deaminases on single- stranded DNA (ssDNA) substrates.
• USER User-Specific Excision Reagent
• Figure 42 is a schematic of the pmCDA-nCas9-UGI-NLS construct and its activity at the HeK-3 site relative to the base editor (rAPOBECl) and the negative control (untreated). This figure depicts SEQ ID NO: 693.
• Figure 43 is a schematic of the pmCDAl-XTEN-nCas9-UGI-NLS construct and its activity at the HeK-3 site relative to the base editor (rAPOBECl) and the negative control (untreated). This figure depicts SEQ ID NO: 694.
• Figure 44 shows the percent of total sequencing reads with target C converted to T using cytidine deaminases (CD A) or APOBEC.
• Figure 45 shows the percent of total sequencing reads with target C converted to A using deaminases (CD A) or APOBEC.
• Figure 46 shows the percent of total sequencing reads with target C converted to G using deaminases (CD A) or APOBEC.
• Figure 47 is a schematic of the huAPOBEC3G-XTEN-nCas9-UGI-NLS construct and its activity at the HeK-2 site relative to a mutated form
• Figure 48 shows the schematic of the LacZ construct used in the selection assay of Example 7.
• Figure 49 shows reversion data from different plasmids and constructs.
• Figure 50 shows the verification of lacZ reversion and the purification of reverted clones.
• Figure 51 is a schematic depicting a deamination selection plasmid used in Example 7.
• Figure 52 shows the results of a chloramphenicol reversion assay (pmCDAl fusion).
• Figures 53A to 53B demonstrated DNA correction induction of two constructs.
• Figure 54 shows the results of a chloramphenicol reversion assay (huAPOBEC3G fusion).
• Figure 55 shows the activities of BE3 and HF-BE3 at EMX1 off-targets.
• Figure 56 shows on-target base editing efficiencies of BE3 and HF-BE3.
• Figure 57 is a graph demonstrating that mutations affect cytidine deamination with varying degrees. Combinations of mutations that each slightly impairs catalysis allow selective deamination at one position over others.
• the FANCF site was
• Figure 58 is a schematic depicting next generation base editors.
• Figure 59 is a schematic illustrating new base editors made from Cas9 variants.
• Figure 60 shows the base-edited percentage of different NGA PAM sites.
• Figure 61 shows the base-edited percentage of cytidines using NGCG PAM EMX (VRER BE3) and the C 1 TC 3 C 4 C 5 ATC 8 AC 10 ATCAACCGGT (SEQ ID NO: 696) spacer.
• Figure 62 shows the based-edited percentages resulting from different NNGRRT PAM sites.
• Figure 63 shows the based-edited percentages resulting from different NNHRRT PAM sites.
• Figures 64A to 64C show the base-edited percentages resulting from different TTTN PAM sites using Cpfl BE2.
• the spacers used were:
• Figure 65 is a schematic depicting selective deamination as achieved through kinetic modulation of cytidine deaminase point mutagenesis.
• Figure 66 is a graph showing the effect of various mutations on the deamination window probed in cell culture with multiple cytidines in the spacer.
• the spacer used was: TGC3C 4 C 5 C6TC 8 C 9 C 10 TC 12 C 1 3C 14 TGGCCC (SEQ ID NO: 700).
• Figure 67 is a graph showing the effect of various mutations on the deamination window probed in cell culture with multiple cytidines in the spacer.
• the spacer used was: AGAGC 5 C 6 C 7 C 8 C 9 C 10 C 11 TC 13 AAAGAGA (SEQ ID NO: 701).
• Figure 68 is a graph showing the effect of various mutations on the FANCF site with a limited number of cytidines.
• the spacer used was:
• Figure 69 is a graph showing the effect of various mutations on the HEK3 site with a limited number of cytidines.
• the spacer used was: GGCC 4 C 5 AGACTGAGCACGTGATGG (SEQ ID NO: 702). Note that the double and triple mutants preferentially edit the cytidine at the fifth position over the cytidine in the fourth position.
• Figure 70 is a graph showing the effect of various mutations on the EMX1 site with a limited number of cytidines.
• the spacer used was:
• Figure 71 is a graph showing the effect of various mutations on the HEK2 site with a limited number of cytidines.
• the spacer used was:
• Figure 72 shows on-target base editing efficiencies of BE3 and BE3 comprising mutations W90Y R132E in immortalized astrocytes.
• Figure 73 depicts a schematic of three Cpfl fusion constructs.
• Figures 74 shows a comparison of plasmid delivery of BE3 and HF-BE3 (EMX1,
• Figure 75 shows a comparison of plasmid delivery of BE3 and HF-BE3 (HEK3 and HEK 4).
• Figure 76 shows off-target editing of EMX-1 at all 10 sites. This figure depicts SEQ ID NOs: 127 and 637-645
• Figure 77 shows deaminase protein lipofection to HEK cells using a
• GAGTCCGAGCAGAAGAAGAAG (SEQ ID NO: 705) spacer.
• the EMX-1 on-target and EMX-1 off target site 2 were examined.
• Figure 78 shows deaminase protein lipofection to HEK cells using a
• Figure 79 shows deaminase protein lipofection to HEK cells using a
• GGCCCAGACTGAGCACGTGA (SEQ ID NO: 707) spacer.
• the HEK- 3 on target site was examined.
• Figure 80 shows deaminase protein lipofection to HEK cells using a
• GGCACTGCGGCTGGAGGTGGGGG (SEQ ID NO: 708) spacer.
• Figure 81 shows the results of an in vitro assay for sgRNA activity for sgHR_13 (GTCAGGTCGAGGGTTCTGTC (SEQ ID NO: 709) spacer; C8 target: G51 to STOP), sgHR_14 (GGGCCGCAGTATCCTCACTC (SEQ ID NO: 710) spacer; C7 target; C7 target: Q68 to STOP), and sgHR_15 (CCGCCAGTCCCAGTACGGGA (SEQ ID NO: 711) spacer; CIO and CI 1 are targets: W239 or W237 to STOP).
• Figure 82 shows the results of an in vitro assay for sgHR_17
• CAACCACTGCTCAAAGATGC (SEQ ID NO: 712) spacer; C4 and C5 are targets: W410 to STOP), and sgHR_16 (CTTCCAGGATGAGAACACAG (SEQ ID NO: 713) spacer; C4 and C5 are targets: W273 to STOP).
• Figure 83 shows the direct injection of BE3 protein complexed with sgHR_13 in zebrafish embryos.
• Figure 84 shows the direct injection of BE3 protein complexed with sgHR_16 in zebrafish embryos.
• Figure 85 shows the direct injection of BE3 protein complexed with sgHR_17 in zebrafish embryos.
• Figure 86 shows exemplary nucleic acid changes that may be made using base editors that are capable of making a cytosine to thymine change.
• Figure 87 shows an illustration of apolipoprotein E (APOE) isoforms
• a base editor e.g., BE3
• one APOE isoform e.g., APOE4
• another APOE isoform e.g., APOE3r
• Figure 88 shows base editing of APOE4 to APOE3r in mouse astrocytes. This figure depicts SEQ ID Nos: 671 and 627.
• Figure 89 shows base editing of PRNP to cause early truncation of the protein at arginine residue 37. This figure depicts SEQ ID Nos: 577 and 714.
• Figure 90 shows that knocking out UDG (which UGI inhibits) dramatically improves the cleanliness of efficiency of C to T base editing.
• Figure 91 shows that use of a base editor with the nickase but without UGI leads to a mixture of outcomes, with very high indel rates.
• Figures 92A to 92G show that SaBE3, SaKKH-BE3, VQR-BE3, EQR-BE3, and VRER-BE3 mediate efficient base editing at target sites containing non-NGG PAMs in human cells.
• Figure 92A shows base editor architectures using S. pyogenes and S. aureus Cas9.
• Figure 92B shows recently characterized Cas9 variants with alternate or relaxed PAM requirements.
• Figures 92C and 92D show HEK293T cells treated with the base editor variants shown as described in Example 12. The percentage of total DNA sequencing reads (with no enrichment for transfected cells) with C converted to T at the target positions indicated are shown. The PAM sequence of each target tested is shown below the X-axis.
• the charts show the results for SaBE3 and SaKKH-BE3 at genomic loci with NNGRRT PAMs ( Figure 92C), SaBE3 and SaKKH-BE3 at genomic loci with NNNRRT PAMs ( Figure 92D), VQR-BE3 and EQR-BE3 at genomic loci with NGAG PAMs ( Figure 92E), and with NGAH PAMs ( Figure 92F), and VRER-BE3 at genomic loci with NGCG PAMs ( Figure 92G).
• Values and error bars reflect the mean and standard deviation of at least two biological replicates.
• Figures 93A to 93C demonstrate that base editors with mutations in the cytidine deaminase domain exhibit narrowed editing windows.
• Figures 93A to 93C show HEK293T cells transfected with plasmids expressing mutant base editors and an appropriate sgRNA. Three days after transfection, genomic DNA was extracted and analyzed by high-throughput DNA sequencing at the indicated loci.
• FIG. 93 A illustrates certain cytidine deaminase mutations which narrow the base editing window. See Figure 98 for the characterization of additional mutations.
• Figure 93B shows the effect of cytidine deaminase mutations which effect the editing window width on genomic loci.
• Figure 93C shows that YE1-BE3, YE2-BE3, EE-BE3, and YEE-BE3 effect the product distribution of base editing, producing predominantly singly- modified products in contrast with BE3. Values and error bars reflect the mean and standard deviation of at least two biological replicates.
• Figures 94A and 94B show genetic variants from ClinVar that in principle can be corrected by the base editors developed in this work.
• the NCBI ClinVar database of human genetic variations and their corresponding phenotypes was searched for genetic diseases that in theory can be corrected by base editing.
• Figure 94A demonstrates improvement in base editing targeting scope among all pathogenic T ⁇ C mutations in the ClinVar database through the use of base editors with altered PAM specificities.
• the white fractions denote the proportion of pathogenic T ⁇ C mutations accessible on the basis of the PAM requirements of either BE3, or BE3 together with the five modified-PAM base editors developed in this work.
• Figure 94B shows improvement in base editing targeting scope among all pathogenic T ⁇ C mutations in the ClinVar database through the use of base editors with narrowed activity windows.
• BE3 was assumed to edit Cs in positions 4-8 with comparable efficiency as shown in Figures 93A to 93C.
• YEE-BE3 was assumed to edit with C5>C6>C7>others preference within its activity window.
• the white fractions denote the proportion of pathogenic T ⁇ C mutations that can be edited BE3 without comparable editing of other Cs (left), or that can be edited BE3 or YEE-BE3 without comparable editing of other Cs (right).
• Figures 95A to 95B show the effect of truncated guide RNAs on base editing window width.
• HEK293T cells were transfected with plasmids expressing BE3 and sgRNAs of different 5' truncation lengths. The treated cells were analyzed as described in the
• Figure 95A shows protospacer and PAM sequence (top, SEQ ID NO: 715) and cellular C to T conversion percentages, defined as the percentage of total DNA sequencing reads with Ts at the target positions indicated, at a site within the EMXl genomic locus. At this site, the base editing window was altered through the use of a 17-nt truncated gRNA.
• Figure 95B shows protospacer and PAM sequences (top, SEQ ID NOs: 715 and 716) and cellular C to T conversion percentages, defined as the percentage of total DNA sequencing reads with Ts at the target positions indicated, at sites within the HEK site 3 and site 4 genomic loci. At these sites, no change in the base editing window was observed, but a linear decrease in editing efficiency for all substrate bases as the sgRNA is truncated was noted.
• Figure 96 shows the effect of APOBECl-Cas9 linker lengths on base editing window width.
• HEK293T cells were transfected with plasmids expressing base editors with rAPOBECl-Cas9 linkers of XTEN, GGS, (GGS) 3 (SEQ ID NO: 610), (GGS) 5 (SEQ ID NO: 610), or (GGS) 7 (SEQ ID NO: 610) and an sgRNA.
• the treated cells were analyzed as described in the Examples.
• Cellular C to T conversion percentages defined as the percentage of total DNA sequencing reads with Ts at the target positions indicated, are shown for the various base editors with different linkers.
• Figures 97A to 97C show the effect of rAPOBEC mutations on base editing window width.
• Figure 97C shows HEK293T cells transfected with plasmids expressing an sgRNA targeting either Site A or Site B and the BE3 point mutants indicated. The treated cells were analyzed as described in the Examples. All C's in the protospacer and within three basepairs of the protospacer are displayed and the cellular C to T conversion percentages are shown. The 'editing window widths', defined as the calculated number of nucleotides within which editing efficiency exceeds the half-maximal value, are displayed for all tested mutants.
• Figure 98 shows the effect of APOBEC1 mutation son product distributions of base editing in mammalian cells.
• HEK293T cells were transfected with plasmids expressing BE3 or its mutants and an appropriate sgRNAs. The treated cells were analyzed as described in the Examples.
• Cellular C to T conversion percentages defined as the percentage of total DNA sequencing reads with Ts at the target positions indicated, are shown (left). Percent of total sequencing reads containing the C to T conversion is shown on the right.
• the BE3 point mutants do not significantly affect base editing efficiencies at HEK site 4, a site with only one target cytidine.
• Figure 99 shows a comparison of on-target editing plasma delivery in BE3 and HF- BE3.
• Figure 100 shows a comparison of on-target editing in protein and plasma delivery of BE3.
• Figure 101 shows a comparison of on-target editing in protein and plasma devliery of HF-BE3.
• Figure 102 shows that both lipofection and installing HF mutations decrease off- target deamination events. The diamond indicates no off targets were detected and the specificity ratio was set to 100.
• Figure 103 shows in vitro C to T editing on a synthetic substrate with Cs placed at even positions in the protospacer (NNNNTC 2 TC 4 TC 6 TC 8 TC 10 TC 12 TC 14 TC 16 TC 18 TC 20 NGG, SEQ ID NO: 723).
• Figure 104 shows in vitro C to T editing on a synthetic substrate with Cs placed at odd positions in the protospacer (NNNNTC 2 TC 4 TC 6 TC 8 TC 10 TC 12 TC 14 TC 16 TC 18 TC 20 NGG, SEQ ID NO: 723).
• Figure 105 includes two graphs depicting the specificity ratio of base editing with plasmid vs. protein delivery.
• Figures 106A to 106B shows BE3 activity on non-NGG PAM sites.
• HEK293T cells were transfected with plasmids expressing BE3 and appropriate sgRNA. The treated cells were analyzed as described in the Examples.
• Figure 106A shows BE3 activity on sites can be efficiently targeted by SaBE3 or SaKKH-BE3.
• BE3 shows low but significant activity on the NAG PAM. This figure depicts SEQ ID NOs: 728 and 729.
• Figure 106B shows BE3 has significantly reduced editing at sites with NGA or NGCG PAMs, in contrast to VQR-BE3 or VRER-BE3. This figure depicts SEQ ID NOs: 730 and 731.
• Figures 107A to 107B show the effect of APOBEC1 mutations on VQR-BE3 and SaKKH-BE3.
• HEK293T cells were transfected with plasmids expressing VQR-BE3, SaKKH- BE3 or its mutants and an appropriate sgRNAs. The treated cells were analyzed as described in the Examples below. Cellular C to T conversion percentages, defined as the percentage of total DNA sequencing reads with Ts at the target positions indicated, are shown.
• Figure 107A shows that the window-modulating mutations can be applied to VQR-BE3 to enable selective base editing at sites targetable by NGA PAM. This figure depicts SEQ ID NOs: 732 and 733.
• Figure 107B shows that, when applied to SaKKH-BE3, the mutations cause overall decrease in base editing efficiency without conferring base selectivity within the target window. This figure depicts SEQ ID NOs: 728 and 734.
• Figure 108 shows a schematic representation of nucleotide editing.
• MMR mismatch repair
• BE3 Nickase refers to base editor 3, which comprises a Cas9 nickase domain
• UMI uracil glycosylase inhibitor
• UDG uracil DNA glycosylase
• APOBEC APOBEC cytidine deaminase.
• Figure 109 shows schematic representations of exemplary base editing constructs.
• the structural arrangement of base editing constructs is shown for BE3, BE4-pmCDAl, BE4- hAID, BE4-3G, BE4-N, BE4-SSB, BE4-(GGS) 3 , BE4-XTEN, BE4-32aa, BE4-2xUGI, and BE4.
• Linkers are shown in grey (XTEN, SGGS (SEQ ID NO: 606), (GGS) 3 (SEQ ID NO: 610), and 32aa).
• Deaminases are shown (rAPOBECl, pmCDAl, hAID, and hAPOBEC3G).
• Uracil DNA Glycosylase Inhibitor (UGI) is shown.
• Single-stranded DNA binding protein is shown in purple.
• Cas9 nickase, dCas9(A840H) is shown in red.
• Figure 109 also shows the following target sequences: EMXl, FANCF, HEK2, HEK3, HEK4, and RNF2.
• the amino acid sequences are indicated in SEQ ID NOs: 127-132 from top to bottom.
• the PAM sequences are the last three nucleotides.
• the target cytosine (C) is numbered and indicated in red.
• Figure 110 shows the base editing results for the indicated base editing constructs (BE3, pmCDAl hAID, hAPOBEC3G, BE4-N, BE4-SSB, BE4-(GGS) 3 , BE-XTEN, BE4- 32aa, and BE4-2xUGI) on the targeted cytoine (C 5 ) of the EMXl sequence,
• GAGTC 5 CGAGCAGAAGAAGAAGGG SEQ ID NO: 127.
• the total percentage of targeted cytosines (C 5 ) that were mutated is indicated for each base editing construct, under "C5".
• the total percentage of indels is indicated for each base editing construct, under "indel”.
• the proportion of mutated cytosines that were mutated to an adenine (A), guanine (G), or thymine (T) are indicated for each base editing construct in the pie chart.
• Figure 111 shows the base editing results for the indicated base editing constructs (BE3, pmCDAl hAID, hAPOBEC3G, BE4-N, BE4-SSB, BE4-(GGS) 3 , BE-XTEN, BE4- 32aa, and BE4-2xUGI) on the targeted cytoine (C 8 ) of the FANCF sequence,
• GGAATCCC 8 TTCTGCAGCACCTGG SEQ ID NO: 128,.
• C 8 targeted cytosines
• Indel indels
• the proportion of mutated cytosines that were mutated to an adenine (A), guanine (G), or thymine (T) are indicated for each base editing construct in the pie chart.
• Figure 112 shows the base editing results for the indicated base editing constructs (BE3, pmCDAl hAID, hAPOBEC3G, BE4-N, BE4-SSB, BE4-(GGS) 3 , BE-XTEN, BE4- 32aa, and BE4-2xUGI) on the targeted cytoine (C 6 ) of the HEK2 sequence,
• GAACAC 6 AAAGCATAGACTGCGGG SEQ ID NO: 129.
• C 6 targeted cytosines
• Indel indels
• Figure 113 shows the base editing results for the indicated base editing constructs (BE3, pmCDAl hAID, hAPOBEC3G, BE4-N, BE4-SSB, BE4-(GGS) 3 , BE-XTEN, BE4- 32aa, and BE4-2xUGI) on the targeted cytoine (C 5 ) of the HEK3 sequence,
• GGCCC 5 AGACTGAGCACGTGATGG SEQ ID NO: 130.
• the total percentage of targeted cytosines (C 5 ) that were mutated are indicated for each base editing construct, under "C5.”.
• the total percentage of indels are indicated for each base editing construct, under "indel”.
• the proportion of mutated cytosines that were mutated to an adenine (A), guanine (G), or thymine (T) are indicated for each base editing construct in the pie chart.
• Figure 114 shows the base editing results for the indicated base editing constructs (BE3, pmCDAl hAID, hAPOBEC3G, BE4-N, BE4-SSB, BE4-(GGS) 3 , BE-XTEN, BE4- 32aa, and BE4-2xUGI) on the targeted cytoine (C 5 ) of the HEK4 sequence,
• GGCAC 5 TGCGGCTGGAGGTCCGGG SEQ ID NO: 131.
• C5. The total percentage of targeted cytosines
• indels are indicated for each base editing construct, under "indel”.
• the proportion of mutated cytosines that were mutated to an adenine (A), guanine (G), or thymine (T) are indicated for each base editing construct in the pie chart.
• Figure 115 shows the base editing results for the indicated base editing constructs (BE3, pmCDAl hAID, hAPOBEC3G, BE4-N, BE4-SSB, BE4-(GGS) 3 , BE-XTEN, BE4- 32aa, and BE4-2xUGI) on the targeted cytoine (C 6 ) of the RNF2 sequence,
• Figure 116 shows exemplary fluorescent labeled (Cy3 labeled) DNA constructs used to test for Cpfl mutants that nick the target strand.
• both the non-target strand (top strand) and target strand (bottom strand) are fluorescently labeled.
• the non-target strand (top strand) is fluorescently labeled and the target strand (bottom strand) is not fluorescently labeled.
• the non- target strand (top strand) is not fluorescently labeled and the target strand (bottom strand) is fluorescently labeled.
• Figure 117 shows data demonstrating the ability of various Cpfl constructs (e.g. , R836A, R1138A, wild-type) to cleave the target and non-target strands of the DNA constructs shown in Figure 116 over the reaction time of either 30 minutes (30 min) or greater than two hours (2h+).
• Cpfl constructs e.g. , R836A, R1138A, wild-type
• Figure 118 shows data demonstrating that a base editor having the architecture, APOBEC-AsCpfl(R912A)-UGI is capable of editing C residues (e.g., of target sequences FANCF1, FANCF2, HEK3-3, and HEK3-4) having a window from the 7 th to the 11 th base of the target sequence.
• BG indicates background mutation levels (untreated).
• AsCpfl indicates AsCpfl only treated (control)
• APOBEC-AsCpfl(R912A)-UGI indicates a base editor containing a Cpfl that preferentially cuts the target strand
• APOBEC-AsCpfl(R1225A)- UGI indicates a self-defeating base editor containing a Cpfl that cuts the non-target strand.
• the target sequences of FANCF1, FANCF2, HEK3-3, and HEK3-4 are as follows:
• FANCF1 GCGGATGTTCCAATCAGTACGCA (SEQ ID NO: 724)
• FANCF2 CGAGCTTCTGGCGGTCTCAAGCA (SEQ ID NO: 725)
• Figure 119 shows a schematic representation of a base editor comprising a Cpfl protein (e.g., AsCpfl or LbCpfl).
• Cpfl protein e.g., AsCpfl or LbCpfl.
• Different linker sequences e.g. , XTEN, GGS, (GGS) 3 (SEQ ID NO: 610), (GGS) 5 (SEQ ID NO: 610), and (GGS) 7 (SEQ ID NO: 610)
• linker sequences e.g. , XTEN, GGS, (GGS) 3 (SEQ ID NO: 610), (GGS) 5 (SEQ ID NO: 610), and (GGS) 7 (SEQ ID NO: 610)
• Figure 120 shows data demonstrating the ability of the construct shown in Figure 119 to edit the C 8 residue of the HEK3 site TGCTTCTC 8 CAGCCCTGGCCTGG (SEQ ID NO: 592).
• Different linker sequences which link the APOBEC domain to the Cpfl domain (e.g., LbCpfl(R836A) or AsCpfl (R912A)) were tested.
• Exemplary linkers that were tested include XTEN, GGS, (GGS) 3 (SEQ ID NO: 610), (GGS) 5 (SEQ ID NO: 610), and (GGS) 7 (SEQ ID NO: 610).
• Figure 121 shows data demonstrating the ability of the construct shown in Figure 119, having the LbCpfl domain, to edit the C 8 and C 9 residues of the HEK3
• TGCTTCTC 8 C 9 AGCCCTGGCCTGG (SEQ ID NO: 592).
• linker sequences from a database maintained by the Centre of Integrative Bioinformatics VU, which link the APOBEC domain to the LbCpfl domain were tested.
• Exemplary linkers that were tested include lau7, lclk, lc20, lee8, lflz, lign, ljmc, lsfe, 2ezx, and 2reb.
• Figure 122 shows a schematic representation of the structure of AsCpfl, where the N and C termini are indicated.
• Figure 123 shows a schematic representation of the structure of SpCas9, where the N and C termini are indicated.
• Figure 124 shows a schematic representation of AsCpfl, where the red circle indicates the predicted area where the editing window is. The square indicates a helical region that may be obstructing APOBEC activity.
• Figures 125A and 125B show engineering and in vitro characterization of a high fidelity base editor (HF-BE3).
• Figure 125A shows a schematic representation of HF-BE3. Point mutations introduced into BE3 to generate HF-BE3 are shown. The representation used PDB structures 4UN3 (Cas9), 4ROV (cytidine deaminase) and 1UGI (uracil DNA glycosylase inhibitor).
• Figure 125B shows in vitro deamination of synthetic substrates containing 'TC repeat protospacers. Values and error bars reflect mean and range of two independent replicates performed on different days.
• Figures 126A to 126C show purification of base editor proteins.
• Figure 126A shows selection of optimal E. coli strain for base editor expression. After IPTG-induced protein expression for 16 h at 18 °C, crude cell lysate was analyzed for protein content.
• BL21 Star (DE3) (Thermo Fisher) cells showed the most promising post-expression levels of both BE3 and HF-BE3 and were used for expression of base editors.
• Figure 126B shows purification of expressed base editor proteins. Placing the His6 tag on the C-terminus of the base editors lead to production of a truncation product for both BE3 and HF-BE3 (lanes 1 and 2).
• Figures 127A to 127D show activity of a high fidelity base editor (HF-BE3) in human cells.
• Figures 127A to 127C show on- and off-target editing associated with plasmid transfection of BE3 and HF-BE3 was assayed using high-throughput sequencing of genomic DNA from HEK293T cells treated with sgRNAs targeting non-repetitive genomic loci EMX1 ( Figure 127A), FANCF ( Figure 127B), and HEK293 site 3 ( Figure 127C).
• On- and off-target loci associated with each sgRNA are separated by a vertical line.
• Figure 127D shows on- and off-target editing associated with the highly repetitive sgRNA targeting VEGFA site 2.
• Figures 128A to 128C show the effect of dosage of BE3 protein or plasmid on the efficiency of on-target and off-target base editing in cultured human cells.
• Figure 128A shows on-target editing efficiency at each of the four genomic loci was averaged across all edited cytosines in the activity window for each sgRNA. Values and error bars reflect mean + S.E.M of three independent biological replicates performed on different days.
• Figures 128B and 128C show on- and off-target editing at the EMX1 site arising from BE3 plasmid titration (Figure 128B) or BE3 protein titration (Figure 128C) in HEK293T cells. Values and error bars reflect mean + S.D. of three independent biological replicates performed on different days.
• Figures 129A to 129B show on-target:off-target base editing frequency ratios for plasmid and protein delivery of BE3 and HF-BE3.
• Base editing on-target:off-target specificity ratios were calculated by dividing the on-target editing percentage at a particular cytosine in the activity window by the off-target editing percentage at the corresponding cytosine for the indicated off-target locus (see Methods).
• off-target editing was below the threshold of detection (0.025% of sequencing reads)
• we set the off-target editing to the limit of detection (0.025%) and divided the on-target editing percentage by this upper limit. In these cases, denoted by ⁇ , the specificity ratios shown represent lower limits.
• Figures 130A to 130D show protein delivery of base editors into cultured human cells.
• Figures 130A to 130D show on- and off-target editing associated with RNP delivery of base editors complexed with sgRNAs targeting EMX1 (Figure 130A), FANCF (Figure 130B), HEK293 site 3 (Figure 130C) and VEGFA site 2 (Figure 130D).
• Off-target base editing was undetectable at all of the sequenced loci for non-repetitive sgRNAs. Values and error bars reflect mean + S.D. of three independent biological replicates performed on different days. Stars indicate significant editing based on a comparison between the treated sample and an untreated control.
• Figures 131A to 131C show indel formation associated with base editing at genomic loci.
• Figure 131A shows indel frequency at on-target loci for VEGFA site 2, EMXl, FANCF, and HEK293 site 3 sgRNAs.
• Figure 131B shows the ratio of base editingdndel formation. The diamond ( ⁇ ) indicates no indels were detected (no significant difference in indel frequency in the treated sample and in the untreated control).
• Figure 131C shows indels observed at the off-target loci associated with the on-target sites interrogated in Figure 131A. Values and error bars reflect mean + S.D. of three independent biological replicates performed on different days.
• Figures 132A to 132D show DNA-free in vivo base editing in zebrafish embryos and in the inner ear of live mice using RNP delivery of BE3.
• Figure 132A shows on-target genome editing in zebrafish harvested 4 days after injection of BE3 complexed with indicated sgRNA. Values and error bars reflect mean + s.d. of three injected and three control zebrafish. Controls were injected with BE3 complexed with an unrelated sgRNA.
• Figure 132B shows schematic showing in vivo injection of BE3: sgRNA complexes encapsulated into cationic lipid nanoparticles
• Figure 132C shows base editing of cytosine residues in the base editor window at the VEGFA site 2 genomic locus.
• Figure 132D shows on-target editing at each cytosine in the base editing window of the VEGFA site 2 target locus.
• Figure 132D ( Figures 132C and 132D) shows values and error bars reflect mean + S.E.M. of three mice injected with sgRNA targeting VEGFA Site 2, three uninjected mice and one mouse injected with unrelated sgRNA.
• Figures 133A to 133E show on- and off-target base editing in murine NIH/3T3 cells.
• Figure 133A shows on-target base editing associated with the 'VEGFA site 2' sgRNA (See Figure 132E for sequences). The negative control corresponds to cells treated with plasmid encoding BE3 but no sgRNA. Values and error bars reflect mean + S.D. of three independent biological replicates performed on different days.
• Figures 133B to 133E show off-target editing associated with this site was measured using high-throughput DNA sequencing at the top four predicted off-target loci for this sgRNA (sequences shown in Figure 132E).
• Figure 133B shows off-target 2
• Figure 133C shows off-target 1
• Figure 133D shows off-target 3
• Figure 133E shows off-target 4. Values and error bars reflect mean + S.D. of three independent biological replicates performed on different days.
• Figures 134A to 134B show off-target base editing and on-target indel analysis from in vivo-edited murine tissue.
• Figure 134A shows editing plotted for each cytosine in the base editing window of off-target loci associated with VEGFA site 2.
• Figure 134B shows indel rates at the on-target base editor locus. Values and error bars reflect mean + S.E.M of three injected and three control mice.
• Figures 135A to 135C show the effects on base editing product purity of knocking out UNG.
• Figure 135A shows HAP1 (UNG + ) and HAP1 UNG cells treated with BE3 as described in the Materials and Methods of Example 17.
• Figure 135B shows protospacers and PAM sequences of the genomic loci tested, with the target Cs analyzed in Figure 135A shown in red.
• Figure 135C shows the frequency of indel formation following treatment with BE3 in HAP1 cells or HAP1 UNG cells. Values and error bars reflect the mean + S.D. of three independent biological replicates performed on different days.
• Figures 136A to 136D show the effects of multi-C base editing on product purity.
• Figure 136A shows representative high-throughput sequencing data of untreated, BE3-treated, and AID-BE3 -treated human HEK293T cells. The sequence of the protospacer is shown at the top, with the PAM and the target Cs in red with subscripted numbers indicating their position within the protospacer. Underneath each sequence are the percentages of total sequencing reads with the corresponding base. The relative percentage of target Cs that are cleanly edited to T rather than to non-T bases is much higher for AID-BE3-treated cells, which edits three Cs at this locus, than for BE3-treated cells, which edits only one C.
• Figure 136B shows
• FIG. 136C shows protospacers and PAM sequences of genomic loci studied, with the target Cs that are analyzed in Figure 136B shown in red.
• Figure 136D shows the frequency of indel formation following the treatment shown in Figure 136A. Values and error bars reflect the mean + S.D. of three independent biological replicates performed on different days.
• Figures 137A to 137C show the effects on C-to-T editing efficiencies and product purities of changing the architecture of BE3.
• Figure 137A shows protospacers and PAM sequences of genomic loci studied, with the target Cs in Figure 137C shown in purple and red, and the target Cs in Figure 137B shown in red.
• Figure 137B shows HEK293T cells treated with BE3, SSB-BE3, N-UGI-BE3, and BE3-2xUGI as described in the Materials and Methods of Example 17.
• the product distribution among edited DNA sequencing reads is shown for BE3, N-UGI-BE3, and BE3-2xUGI.
• Figure 137C shows C-to-T base editing efficiencies. Values and error bars reflect the mean + S.D. of three independent biological replicates performed on different days.
• Figures 138A to 138D show the effects of linker length variation in BE3 on C-to-T editing efficiencies and product purities.
• Figure 138A shows the architecture of BE3, BE3C, BE3D, and BE3E
• Figure 138B shows protospacers and PAM sequences of genomic loci studied, with the target Cs in Figure 138C shown in purple and red, and target Cs in Figure 138D shown in red.
• Figure 138C shows HEK293T cells treated with BE3, BE3C, BE3D, or BE3E as described in the Materials and Methods of Example 17. C-to-T base editing efficiencies are shown.
• Figure 138D shows the product distribution among edited DNA sequencing reads (reads in which the target C is mutated) for BE3, BE3C, BE3D, and BE3E. Values and error bars reflect the mean + S.D. of three independent biological replicates performed on different days.
• Figures 139A to 139D show BE4 increases base editing efficiency and product purities compared to BE3.
• Figure 139A shows the architectures of BE3, BE4, and Target- AID.
• Figure 139B shows protospacers and PAM sequences of genomic loci studied, with the target Cs in Figure 139C shown in purple and red, and the target Cs in Figure 139D shown in red.
• Figure 139C shows HEK293T cells treated with BE3, BE4, or Target- AID as described in the Materials and Methods of Example 17. C-to-T base editing efficiencies are shown.
• Figure 139D shows the product distribution among edited DNA sequencing reads (reads in which the target C is mutated) for BE3 and BE4. Values and error bars reflect the mean + S.D. of three independent biological replicates performed on different days.
• Figures 140A to 140C show CDA1-BE3 and AID-BE3 edit Cs following target Gs more efficiently than BE3.
• Figure 140A shows protospacer and PAM sequences of genomic loci studied, with target Cs edited by BE3, CDA1-BE3, and AID-BE3 shown in red, and target Cs (following Gs) edited by CDA1-BE3 and AID-BE3 only shown in purple.
• Figure 140B shows HEK293T cells treated with BE3, CDA1-BE3, AID-BE3, or APOBEC3G-BE3 as described in the Materials and Methods of Example 17. C-to-T base editing efficiencies are shown.
• Figure 140C shows individual DNA sequencing reads from HEK293T cells that were treated with BE3, CDA1-BE3, or AID-BE3 targeting the HEK2 locus and binned according to the sequence of the protospacer and analyzed, revealing that > 85% of sequencing reads that have clean C to Tedits by CDA1-BE3 and AID-BE3 have both Cs edited to T (Figure 140C).
• Figures 141A to 141C show uneven editing in sites with multiple editable Cs results in lower product purity.
• Figure 141A shows protospacers and PAM sequences of genomic loci studied, with the target Cs in Figure 141C shown in purple and red, and target Cs in Figure 141B shown in red.
• Figures 141B and 141C show HEK293T cells treated with BE3 as described in the Materials and Methods of Example 17. The product distribution among edited DNA sequencing reads (reads in which the target C is mutated) is shown.
• C to non-T editing is more frequent when editing efficiencies are unequal for two Cs within the same locus. Values and error bars reflect the mean + S.D. of three independent biological replicates performed on different days.
• Figures 142A to 142D show base editing of multiple Cs results in higher base editing product purity.
• Figure 142A shows protospacers and PAM sequences of genomic loci studied, with the target Cs that are investigated in Figure 142B shown in red.
• Figure 142B shows HEK293T cells treated with BE3 or BE3B (which lacks UGI) as described in the Materials and Methods of Example 17. The product distribution among edited DNA sequencing reads (reads in which the target C is mutated) is shown.
• Figure 142C shows the HTS reads from HEK293T cells that were treated with BE3 or BE3B (which lacks UGI) targeting the HEK2 locus were binned according to the identity of the primary target C at position 6.
• Figure 142D shows the distribution of edited reads with A, G, and T at C5 in cells treated with BE3 or BE3B targeting the HEK4 locus (a site with only a single editable C), illustrating that single G:U mismatches are processed via UNG-initiated base excision repair to give a mixture of products. Values and error bars reflect the mean + S.D. of three independent biological replicates performed on different days.
• Figure 143 shows base editing of multiple Cs results in higher base editing product purity at the HEK3 and RNF2 loci.
• DNA sequencing reads from HEK293T cells treated with BE3 or BE3B (without UGI) targeting the HEK3 and RNF2 loci were separated according to the identity of the base at the primary target C position (in red). The four groups of sequencing reads were then interrogated for the identity of the base at the secondary target C position (in purple).
• the primary target C (in red) is incorrectly edited to G, the secondary target C is more likely to remain C.
• the primary target C (in red) is converted to T, the secondary target C is more likely to also be edited to a T in the same sequencing read.
• Values and error bars reflect the mean + S.D. of three independent biological replicates performed on different days.
• Figures 144A to 144C show BE4 induces lower indel frequencies than BE3, and Target-AID exhibits similar product purities as CDA1-BE3.
• Figure 144A shows HEK293T cells treated with BE3, BE4, or Target-AID as described in the Materials and Methods of Example 17. The frequency of indel formation (see Materials and Methods of Example 17) is shown.
• Figure 144B shows HEK293T cells treated with CDA1-BE3 or Target-AID as described in the Materials and Methods of Example 17.
• the product distribution among edited DNA sequencing reads reads in which the target C is mutated
• Figure 144C shows protospacers and PAM sequences of genomic loci studied, with the target Cs that are investigated in Figure 144B shown in red. Values and error bars reflect the mean + S.D. of three independent biological replicates performed on different days.
• Figures 145A to 145C show SaBE4 exhibits increased base editing yields and product purities compared to SaBE3.
• Figure 145A shows HEK293T cells treated with SaBE3 and SaBE4 as described in the Materials and Methods of Example 17. The percentage of total DNA sequencing reads with Ts at the target positions indicated are shown.
• Figure 145B shows protospacers and PAM sequences of genomic loci studied, with the target Cs in Figure 145A shown in purple and red, with target Cs that are investigated in Figure 145C shown in red.
• Figure 145C shows the product distribution among edited DNA sequencing reads (reads in which the target C is mutated). Values and error bars reflect the mean + S.D. of three independent biological replicates performed on different days.
• Figure 146 shows base editing outcomes from treatment with BE3, CDA1-BE3, AID-BE3, or APOBEC3G-BE3 at the EMX1 locus.
• the sequence of the protospacer is shown at the top, with the PAM and the target bases in red with a subscripted number indicating their positions within the protospacer. Underneath the sequence are the percentages of total sequencing reads with the corresponding base.
• Cells were treated as described in the Materials and Methods of Example 17. Values shown are from one representative experiment.
• Figure 147 shows base editing outcomes from treatment with BE3, CDA1-BE3, AID-BE3, or APOBEC3 G-BE3 at the FANCF locus.
• the sequence of the protospacer is shown at the top, with the PAM and the target bases in red with a subscripted number indicating their positions within the protospacer. Underneath the sequence are the percentages of total sequencing reads with the corresponding base.
• Cells were treated as described in the Materials and Methods of Example 17. Values shown are from one representative experiment.
• Figure 148 shows base editing outcomes from treatment with BE3, CDA1-BE3, AID-BE3, or APOBEC3G-BE3 at the HEK2 locus.
• the sequence of the protospacer is shown at the top, with the PAM and the target bases in red with a subscripted number indicating their positions within the protospacer. Underneath the sequence are the percentages of total sequencing reads with the corresponding base.
• Cells were treated as described in the Materials and Methods of Example 17. Values shown are from one representative experiment.
• Figure 149 shows base editing outcomes from treatment with BE3, CDA1-BE3, AID-BE3, or APOBEC3G-BE3 at the HEK3 locus.
• the sequence of the protospacer is shown at the top, with the PAM and the target bases in red with a subscripted number indicating their positions within the protospacer. Underneath the sequence are the percentages of total sequencing reads with the corresponding base.
• Cells were treated as described in the Materials and Methods of Example 17. Values shown are from one representative experiment.
• Figure 150 shows base editing outcomes from treatment with BE3, CDA1-BE3, AID-BE3, or APOBEC3G-BE3 at the HEK4 locus.
• the sequence of the protospacer is shown at the top, with the PAM and the target bases in red with a subscripted number indicating their positions within the protospacer. Underneath the sequence are the percentages of total sequencing reads with the corresponding base.
• Cells were treated as described in the Materials and Methods of Example 17. Values shown are from one representative experiment.
• Figure 151 shows base editing outcomes from treatment with BE3, CDA1-BE3, AID-BE3, or APOBEC3G-BE3 at the RNF2 locus.
• the sequence of the protospacer is shown at the top, with the PAM and the target bases in red with a subscripted number indicating their positions within the protospacer. Underneath the sequence are the percentages of total sequencing reads with the corresponding base.
• Cells were treated as described in the Materials and Methods of Example 17. Values shown are from one representative experiment.
• FIG. 152 shows a schematic of LBCpf 1 fusion constructs.
• Construct 10 has a domain arrangement of [Apobec]-[LbCpfl]-[UGI]-[UGI]; construct 11 has a domain arrangement of [Apobec]-[LbCpfl]-[UGI]; construct 12 has a domain arrangement of [UGI]- [Apobec]-[LbCpfl]; construct 13 has a domain arrangement of [Apobec]-[UGI]-[LbCpfl]; construct 14 has a domain arrangement of [LbCpfl]-[UGI]-[Apobec]; construct 15 has a domain arrangement of [LbCpfl]-[Apobec]-[UGI].
• D/N/A which refers to nuclease dead LbCpfl (D); LbCpfl nickase (N) and nuclease active LbCpfl (D/N/A, which refers to nucle
• Figure 153 shows the percentage of C to T editing of six C residues in the EMX target TTTGT AC 3 TTTGTC 9 C 1 oTC 12C 13 GGTTC 18 TG (SEQ ID NO: 738) using a guide of 19 nucleotides in length, i.e., EMX19: TACTTTGTCCTCCGGTTCT (SEQ ID NO: 744). Editing was tested for several of the constructs shown in Figure 152.
• Figure 154 shows the percentage of C to T editing of six C residues in the EMX target TTTGT AC 3 TTTGTC 9 C 1 oTC 12C 13 GGTTC 18 TG (SEQ ID NO: 738) using a guide of 18 nucleotides in length, i.e., EMX18: TACTTTGTCCTCCGGTTC (SEQ ID NO: 745). Editing was tested for several of the constructs shown in Figure 152.
• Figure 155 shows the percentage of C to T editing of six C residues in the EMX target TTTGT AC 3 TTTGTC 9 C 1 oTC 12C 13 GGTTC 18 TG (SEQ ID NO: 738) using a guide of 17 nucleotides in length, i.e., EMX17: TACTTTGTCCTCCGGTT (SEQ ID NO: 746). Editing was tested for several of the constructs shown in Figure 152.
• Figure 156 shows the percentage of C to T editing of eight C residues in the HEK2 target TTTCC 1 AGC 4 C 5 C 6 GC 8 TGGC 12 C 13 C 14 TGTAAA (SEQ ID NO: 739) using a guide of 23 nucleotides in length, i.e., Hek2_23: CAGCCCGCTGGCCCTGTAAAGGA (SEQ ID NO: 747). Editing was tested for several of the constructs shown in Figure 152.
• Figure 157 shows the percentage of C to T editing of eight C residues in the HEK2 target TTTCC 1 AGC 4 C 5 C 6 GC 8 TGGC 12 C 13 C 14 TGTAAA (SEQ ID NO: 739) using a guide of 20 nucleotides in length, i.e., Hek2_20: CAGCCCGCTGGCCCTGTAAA (SEQ ID NO: 748). Editing was tested for several of the constructs shown in Figure 152.
• Figure 158 shows the percentage of C to T editing of eight C residues in the HEK2 target TTTCC 1 AGC 4 C 5 C 6 GC 8 TGGC 12 C 13 C 14 TGTAAA (SEQ ID NO: 739) using a guide of 19 nucleotides in length, i.e., Hek2_19: CAGCCCGCTGGCCCTGTAA (SEQ ID NO: 749). Editing was tested for several of the constructs shown in Figure 152.
• Figure 159 shows the percentage of C to T editing of eight C residues in the HEK2 target TTTCC 1 AGC 4 C 5 C 6 GC 8 TGGC 12 C 13 C 14 TGTAAA (SEQ ID NO: 739) using a guide of
• Hek2_18 CAGCCCGCTGGCCCTGTA (SEQ ID NO: 750).
• Figure 160 shows the editing percentage values (after adjustment based on indel count), and the percentage of indels for the experiments depicted in figure 153.
• Figure 161 shows the editing percentage values (after adjustment based on indel count), and the percentage of indels for the experiments depicted in figure 154.
• Figure 162 shows the editing percentage values (after adjustment based on indel count), and the percentage of indels for the experiments depicted in figure 155.
• Figure 163 shows the editing percentage values (after adjustment based on indel count), and the percentage of indels for the experiments depicted in figure 156.
• Figure 164 shows the editing percentage values (after adjustment based on indel count), and the percentage of indels for the experiments depicted in figure 157.
• Figure 165 shows the editing percentage values (after adjustment based on indel count), and the percentage of indels for the experiments depicted in figure 158.
• Figure 166 shows the editing percentage values (after adjustment based on indel count), and the percentage of indels for the experiments depicted in figure 159.
• nucleic acid programmable DNA binding protein refers to a protein that associates with a nucleic acid (e.g., DNA or RNA), such as a guide nucleic acid (e.g. , gRNA), that guides the napDNAbp to a specific nucleic acid sequence, for example, by hybridinzing to the target nucleic acid sequence.
• a Cas9 protein can associate with a guide RNA that guides the Cas9 protein to a specific DNA sequence is has
• the napDNAbp is a class 2 microbial CRISPR-Cas effector.
• the napDNAbp is a Cas9 domain, for example, a nuclease active Cas9, a Cas9 nickase (nCas9), or a nuclease inactive Cas9 (dCas9).
• nucleic acid programmable DNA binding proteins include, without limitation, Cas9 (e.g., dCas9 and nCas9), CasX, CasY, Cpfl, C2cl, C2c2, C2C3, and Argonaute.
• nucleic acid programmable DNA binding proteins also include nucleic acid programmable proteins that bind RNA.
• the napDNAbp may be associated with a nucleic acid that guides the napDNAbp to an RNA.
• Other nucleic acid programmable DNA binding proteins are also within the scope of this disclosure, though they may not be specifically described in this disclosure.
• the napDNAby is an "RNA -programmable nuclease" or "RNA-guided nuclease.”
• RNA-programmable nuclease or "RNA-guided nuclease.”
• the terms are used interchangeably herein and refer to a nuclease that forms a complex with (e.g. , binds or associates with) one or more RNA(s) that is not a target for cleavage.
• an RNA-programmable nuclease when in a complex with an RNA, may be referred to as a nuclease:RNA complex.
• the bound RNA(s) is referred to as a guide RNA (gRNA).
• gRNAs can exist as a complex of two or more RNAs, or as a single RNA molecule. gRNAs that exist as a single RNA molecule may be referred to as single-guide RNAs (sgRNAs), though "gRNA” is also used to refer to guide RNAs that exist as either single molecules or as a complex of two or more molecules.
• sgRNAs single-guide RNAs
• gRNAs that exist as a single RNA species comprise two domains: (1) a domain that shares homology to a target nucleic acid (i.e., directs binding of a Cas9 complex to the target); and (2) a domain that binds a Cas9 protein.
• domain (2) corresponds to a sequence known as a tracrRNA and comprises a stem-loop structure.
• domain (2) is identical or homologous to a tracrRNA as provided in Jinek et ah , Science 337:816-821 (2012), the entire contents of which is incorporated herein by reference.
• Other examples of gRNAs e.g., those including domain 2 can be found in U.S.
• a gRNA comprises two or more of domains (1) and (2), and may be referred to as an "extended gRNA.”
• an extended gRNA will bind two or more Cas9 proteins and bind a target nucleic acid at two or more distinct regions, as described herein.
• the gRNA comprises a nucleotide sequence that complements a target site, which mediates binding of the nuclease/RNA complex to said target site, providing the sequence specificity of the nuclease:RNA complex.
• the RNA-programmable nuclease is the (CRIS PR-associated system) Cas9 endonuclease, for example, Cas9 (Csnl) from Streptococcus pyogenes (see, e.g., "Complete genome sequence of an Ml strain of Streptococcus pyogenes.” Ferretti J.
• any of the sgRNAs provided herein comprise a sequence, e.g., a sgRNA backbone sequence that binds to a napDNAbp.
• a sgRNA backbone sequence that binds to a napDNAbp.
• sgRNAs have been described in Jinek M, Chylinski K, Fonfara I, Hauer M, Doudna JA, and Charpentier E (2012) A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity. Science, 337, 816-812; Mali P, Esvelt KM, Church GM (2013) Cas9 as a versatile tool for engineering biology. Nature Methods, 10, 957-963; Li JF, Norville JE, Aach J, McCromack M, Zhang D, Bush J, Church GM, and Sheen J (2013) Multiplex and homologous
• any of the gRNAs (e.g., sgRNAs) provided herin comprise the nucleic acid sequence of GTAATTTCTACTAAGTGTAGAT (SEQ ID NO: 741), wherein each of the Ts of SEQ ID NO: 741 are uracil (U), i.e., GUAAUUUCUACUAAGUGUAGAU, or the sequence
• RNA -programmable nucleases e.g., Cas9
• Cas9 RNA:DNA hybridization to target DNA cleavage sites
• Methods of using RNA-programmable nucleases, such as Cas9, for site-specific cleavage (e.g., to modify a genome) are known in the art (see e.g., Cong, L. et ah, Multiplex genome engineering using CRISPR/Cas systems. Science 339, 819-823 (2013); Mali, P. et ah, RNA-guided human genome engineering via Cas9. Science 339, 823-826 (2013); Hwang, W.Y.
• et ah Efficient genome editing in zebrafish using a CRISPR-Cas system. Nature biotechnology 31, 227-229 (2013); Jinek, M. et ah RNA-programmed genome editing in human cells. eLife 2, e00471 (2013); Dicarlo, J.E. et ah, Genome engineering in Saccharomyces cerevisiae using CRISPR-Cas systems. Nucleic Acids Research (2013); Jiang, W. et ah, RNA-guided editing of bacterial genomes using CRISPR-Cas systems. Nature Biotechnology 31, 233-239 (2013); the entire contents of each of which are incorporated herein by reference).
• Cas9 or “Cas9 nuclease” refers to an RNA-guided nuclease comprising a Cas9 protein, or a fragment thereof (e.g., a protein comprising an active, inactive, or partially active DNA cleavage domain of Cas9, and/or the gRNA binding domain of Cas9).
• a Cas9 nuclease is also referred to sometimes as a casnl nuclease or a CRISPR (clustered regularly interspaced short palindromic repeat)-associated nuclease.
• CRISPR is an adaptive immune system that provides protection against mobile genetic elements (viruses, transposable elements and conjugative plasmids).
• CRISPR clusters contain spacers, sequences complementary to antecedent mobile elements, and target invading nucleic acids. CRISPR clusters are transcribed and processed into CRISPR RNA (crRNA). In type II CRISPR systems correct processing of pre-crRNA requires a trans-encoded small RNA (tracrRNA), endogenous ribonuclease 3 (rnc) and a Cas9 protein. The tracrRNA serves as a guide for ribonuclease 3-aided processing of pre-crRNA. Subsequently, Cas9/crRNA/tracrRNA endonucleolytically cleaves linear or circular dsDNA target complementary to the spacer.
• tracrRNA trans-encoded small RNA
• rnc endogenous ribonuclease 3
• Cas9 protein serves as a guide for ribonuclease 3-aided processing of pre-crRNA.
• sgRNA single guide RNAs
• gNRA single guide RNAs
• Cas9 recognizes a short motif in the CRISPR repeat sequences (the PAM or protospacer adjacent motif) to help distinguish self versus non-self.
• Cas9 nuclease sequences and structures are well known to those of skill in the art (see, e.g., "Complete genome sequence of an Ml strain of
• Cas9 orthologs have been described in various species, including, but not limited to, S. pyogenes and S. thermophilus . Additional suitable Cas9 nucleases and sequences will be apparent to those of skill in the art based on this disclosure, and such Cas9 nucleases and sequences include Cas9 sequences from the organisms and loci disclosed in Chylinski, Rhun, and Charpentier, "The tracrRNA and Cas9 families of type II CRISPR-Cas immunity systems" (2013) RNA Biology 10:5, 726-737; the entire contents of which are incorporated herein by reference.
• a Cas9 nuclease has an inactive ⁇ e.g., an inactivated) DNA cleavage domain, that is, the Cas9 is a nickase.
• a nuclease-inactivated Cas9 protein may interchangeably be referred to as a "dCas9" protein (for nuclease-"dead” Cas9).
• Methods for generating a Cas9 protein (or a fragment thereof) having an inactive DNA cleavage domain are known (See, e.g., Jinek et al, Science.
• the DNA cleavage domain of Cas9 is known to include two subdomains, the HNH nuclease subdomain and the RuvCl subdomain.
• the HNH subdomain cleaves the strand complementary to the gRNA, whereas the RuvCl subdomain cleaves the non-complementary strand. Mutations within these subdomains can silence the nuclease activity of Cas9.
• proteins comprising fragments of Cas9 are provided.
• a protein comprises one of two Cas9 domains: (1) the gRNA binding domain of Cas9; or (2) the DNA cleavage domain of Cas9.
• proteins comprising Cas9 or fragments thereof are referred to as "Cas9 variants.”
• a Cas9 variant shares homology to Cas9, or a fragment thereof.
• a Cas9 variant is at least about 70% identical, at least about 80% identical, at least about 90% identical, at least about 95% identical, at least about 96% identical, at least about 97% identical, at least about 98% identical, at least about 99% identical, at least about 99.5% identical, or at least about 99.9% identical to wild type Cas9.
• the Cas9 variant may have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 21, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 or more amino acid changes compared to wild type Cas9.
• the Cas9 variant comprises a fragment of Cas9 ⁇ e.g., a gRNA binding domain or a DNA-cleavage domain), such that the fragment is at least about 70% identical, at least about 80% identical, at least about 90% identical, at least about 95% identical, at least about 96% identical, at least about 97% identical, at least about 98% identical, at least about 99% identical, at least about 99.5% identical, or at least about 99.9% identical to the corresponding fragment of wild type Cas9.
• a fragment of Cas9 ⁇ e.g., a gRNA binding domain or a DNA-cleavage domain
• the fragment is at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95% identical, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.5% of the amino acid length of a corresponding wild type Cas9.
• the fragment is at least 100 amino acids in length.
• the fragment is at least 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, or at least 1300 amino acids in length.
• wild type Cas9 corresponds to Cas9 from
• nucleotide SEQ ID NO: 2 (amino acid)
• wild type Cas9 corresponds to, or comprises SEQ ID NO:3 (nucleotide) and/or SEQ ID NO: 4 (amino acid):
• wild type Cas9 corresponds to Cas9 from Streptococcus pyogenes (NCBI Reference Sequence: NC_002737.2, SEQ ID NO: 5 (nucleotide); and Uniport Reference Sequence: Q99ZW2, SEQ ID NO: 6 (amino acid).
• YTSTKEVLDATLIHQSITGLYETRIDLSQLGGD (SEQ ID NO: 6) (single underline: HNH domain; double underline: RuvC domain)
• Cas9 refers to Cas9 from: Corynebacterium ulcerans (NCBI Refs: NC 015683.1, NC_017317.1); Corynebacterium diphtheria (NCBI Refs: NC 016782.1, NC_016786.1); Spiroplasma syrphidicola (NCBI Ref: NC_021284.1); Prevotella intermedia (NCBI Ref: NC 017861.1); Spiroplasma taiwanense (NCBI Ref: NC_021846.1);
• NCBI Ref Streptococcus iniae
• Belliella baltica NCBI Ref: NC_018010.1
• Psychroflexus torquisl NCBI Ref: NC_018721.1
• Streptococcus thermophilus NCBI Ref: YP_820832.1
• Listeria innocua NCBI Ref: NP_472073.1
• Campylobacter jejuni NCBI Ref: YP_002344900.1
• Neisseria, meningitidis NCBI Ref: YP_002342100.1 or to a Cas9 from any of the organisms listed in Example 5.
• dCas9 corresponds to, or comprises in part or in whole, a Cas9 amino acid sequence having one or more mutations that inactivate the Cas9 nuclease activity.
• a dCas9 domain comprises D10A and/or H840A mutation.
• the Cas9 domain comprises a D10A mutation, while the residue at position 840 remains a histidine in the amino acid sequence provided in SEQ ID NO: 6, or at corresponding positions in any of the amino acid sequences provided in another Cas9 domain, such as any of the Cas9 proteins provided herein.
• the presence of the catalytic residue H840 restores the acvitity of the Cas9 to cleave the non-edited (e.g., non-deaminated) strand containing a G opposite the targeted C.
• Restoration of H840 does not result in the cleavage of the target strand containing the C.
• Such Cas9 variants are able to generate a single-strand DNA break (nick) at a specific location based on the gRNA-defined target sequence, leading to repair of the non-edited strand, ultimately resulting in a G to A change on the non-edited strand.
• a schematic representation of this process is shown in Figure 108.
• the C of a C-G basepair can be deaminated to a U by a deaminase, e.g., an APOBEC deamonase.
• a deaminase e.g., an APOBEC deamonase.
• Nicking the non-edited strand, having the G facilitates removal of the G via mismatch repair mechanisms.
• UGI inhibits UDG, which prevents removal of the U.
• dCas9 variants having mutations other than D10A and H840A are provided, which, e.g., result in nuclease inactivated Cas9 (dCas9).
• Such mutations include other amino acid substitutions at D10 and H820, or other substitutions within the nuclease domains of Cas9 (e.g., substitutions in the HNH nuclease subdomain and/or the RuvCl subdomain).
• variants or homologues of dCas9 are provided which are at least about 70% identical, at least about 80% identical, at least about 90% identical, at least about 95% identical, at least about 98% identical, at least about 99% identical, at least about 99.5% identical, or at least about 99.9% identical to SEQ ID NO: 6.
• variants of dCas9 are provided having amino acid sequences which are shorter, or longer than SEQ ID NO: 6, by about 5 amino acids, by about 10 amino acids, by about 15 amino acids, by about 20 amino acids, by about 25 amino acids, by about 30 amino acids, by about 40 amino acids, by about 50 amino acids, by about 75 amino acids, by about 100 amino acids or more.
• Cas9 fusion proteins as provided herein comprise the full- length amino acid sequence of a Cas9 protein, e.g., one of the Cas9 sequences provided herein. In other embodiments, however, fusion proteins as provided herein do not comprise a full- length Cas9 sequence, but only a fragment thereof.
• a Cas9 fusion protein provided herein comprises a Cas9 fragment, wherein the fragment binds crRNA and tracrRNA or sgRNA, but does not comprise a functional nuclease domain, e.g., in that it comprises only a truncated version of a nuclease domain or no nuclease domain at all.
• Exemplary amino acid sequences of suitable Cas9 domains and Cas9 fragments are provided herein, and additional suitable sequences of Cas9 domains and fragments will be apparent to those of skill in the art.
• Cas9 refers to Cas9 from: Corynebacterium ulcerans (NCBI Refs: NC 015683.1, NC_017317.1); Corynebacterium diphtheria (NCBI Refs: NC 016782.1, NC_016786.1); Spiroplasma syrphidicola (NCBI Ref: NC_021284.1); Prevotella intermedia (NCBI Ref: NC 017861.1); Spiroplasma taiwanense (NCBI Ref: NC_021846.1);
• NCBI Ref Streptococcus iniae
• NCBI Ref NC_021314.1
• Belliella baltica NCBI Ref: NC_018010.1
• Psychroflexus torquis I NCBI Ref: NC_018721.1
• Streptococcus thermophilus NCBI Ref: YP_820832.1
• Listeria innocua NCBI Ref: NP_472073.1
• Campylobacter jejuni NCBI Ref: YP_002344900.1
• Neisseria, meningitidis NCBI Ref: YP_002342100.1
• deaminase or “deaminase domain,” as used herein, refers to a protein or enzyme that catalyzes a deamination reaction.
• the deaminase or deaminase domain is a cytidine deaminase, catalyzing the hydrolytic deamination of cytidine or deoxycytidine to uridine or deoxyuridine, respectively.
• the deaminase or deaminase domain is a cytidine deaminase domain, catalyzing the hydrolytic deamination of cytosine to uracil.
• the deaminase or deaminase domain is a naturally-occuring deaminase from an organism, such as a human, chimpanzee, gorilla, monkey, cow, dog, rat, or mouse. In some embodiments, the deaminase or deaminase domain is a variant of a naturally-occuring deaminase from an organism, that does not occur in nature.
• the deaminase or deaminase domain is at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75% at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.5% identical to a naturally-occuring deaminase from an organism.
• an effective amount refers to an amount of a biologically active agent that is sufficient to elicit a desired biological response.
• an effective amount of a nuclease may refer to the amount of the nuclease that is sufficient to induce cleavage of a target site specifically bound and cleaved by the nuclease.
• an effective amount of a fusion protein provided herein may refer to the amount of the fusion protein that is sufficient to induce editing of a target site specifically bound and edited by the fusion protein.
• an agent e.g., a fusion protein, a nuclease, a deaminase, a recombinase, a hybrid protein, a protein dimer, a complex of a protein (or protein dimer) and a polynucleotide, or a polynucleotide
• an agent e.g., a fusion protein, a nuclease, a deaminase, a recombinase, a hybrid protein, a protein dimer, a complex of a protein (or protein dimer) and a polynucleotide, or a polynucleotide
• the desired biological response e.g., on the specific allele, genome, or target site to be edited, on the cell or tissue being targeted, and on the agent being used.
• linker refers to a chemical group or a molecule linking two molecules or moieties, e.g., two domains of a fusion protein, such as, for example, a nuclease-inactive Cas9 domain and a nucleic acid editing domain ⁇ e.g., a deaminase domain).
• a linker may be, for example, an amino acid sequence, a peptide, or a polymer of any length and compostion.
• a linker joins a gRNA binding domain of an RNA- programmable nuclease, including a Cas9 nuclease domain, and the catalytic domain of anucleic-acid editing protein.
• a linker joins a dCas9 and a nucleic-acid editing protein.
• the linker is positioned between, or flanked by, two groups, molecules, or other moieties and connected to each one via a covalent bond, thus connecting the two.
• the linker is an amino acid or a plurality of amino acids (e.g., a peptide or protein).
• the linker is an organic molecule, group, polymer, or chemical moiety.
• the linker is 1-100 amino acids in length, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 30-35, 35-40, 40-45, 45-50, 50-60, 60-70, 70-80, 80-90, 90-100, 100-150, or 150-200 amino acids in length. Longer or shorter linkers are also contemplated.
• mutation refers to a substitution of a residue within a sequence, e.g., a nucleic acid or amino acid sequence, with another residue, or a deletion or insertion of one or more residues within a sequence. Mutations are typically described herein by identifying the original residue followed by the position of the residue within the sequence and by the identity of the newly substituted residue. Various methods for making the amino acid substitutions (mutations) provided herein are well known in the art, and are provided by, for example, Green and Sambrook, Molecular Cloning: A Laboratory Manual (4 th ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (2012)).
• nucleic acid and “nucleic acid molecule,” as used herein, refer to a compound comprising a nucleobase and an acidic moiety, e.g., a nucleoside, a nucleotide, or a polymer of nucleotides.
• polymeric nucleic acids e.g., nucleic acid molecules comprising three or more nucleotides are linear molecules, in which adjacent nucleotides are linked to each other via a phosphodiester linkage.
• nucleic acid refers to individual nucleic acid residues (e.g. nucleotides and/or nucleosides).
• nucleic acid refers to an oligonucleotide chain comprising three or more individual nucleotide residues.
• oligonucleotide and
• nucleic acid can be used interchangeably to refer to a polymer of nucleotides (e.g., a string of at least three nucleotides).
• nucleic acid encompasses RNA as well as single and/or double-stranded DNA. Nucleic acids may be naturally occurring, for example, in the context of a genome, a transcript, an mRNA, tRNA, rRNA, siRNA, snRNA, a plasmid, cosmid, chromosome, chromatid, or other naturally occurring nucleic acid molecule.
• a nucleic acid molecule may be a non-naturally occurring molecule, e.g., a recombinant DNA or RNA, an artificial chromosome, an engineered genome, or fragment thereof, or a synthetic DNA, RNA, DNA/RNA hybrid, or including non-naturally occurring nucleotides or nucleosides.
• nucleic acid DNA
• RNA and/or similar terms include nucleic acid analogs, e.g., analogs having other than a phosphodiester backbone.
• Nucleic acids can be purified from natural sources, produced using recombinant expression systems and optionally purified, chemically synthesized, etc. Where appropriate, e.g.
• nucleic acids in the case of chemically synthesized molecules, can comprise nucleoside analogs such as analogs having chemically modified bases or sugars, and backbone modifications.
• a nucleic acid sequence is presented in the 5' to 3' direction unless otherwise indicated.
• a nucleic acid is or comprises natural nucleosides (e.g. adenosine, thymidine, guanosine, cytidine, uridine, deoxyadenosine, deoxythymidine, deoxyguanosine, and deoxycytidine); nucleoside analogs (e.g.
• methylated bases e.g. , methylated bases); intercalated bases; modified sugars (e.g. , 2'-fluororibose, ribose, 2'-deoxyribose, arabinose, and hexose); and/or modified phosphate groups (e.g., phosphorothioates and 5'-N-phosphoramidite linkages).
• modified sugars e.g. , 2'-fluororibose, ribose, 2'-deoxyribose, arabinose, and hexose
• modified phosphate groups e.g., phosphorothioates and 5'-N-phosphoramidite linkages.
• nucleic acid editing domain refers to a protein or enzyme capable of making one or more modifications (e.g., deamination of a cytidine residue) to a nucleic acid (e.g., DNA or RNA).
• exemplary nucleic acid editing domains include, but are not limited to a deaminase, a nuclease, a nickase, a recombinase, a methyltransferase, a methylase, an acetylase, an acetyltransferase, a transcriptional activator, or a transcriptional repressor domain.
• the nucleic acid editing domain is a deaminase (e.g., a cytidine deaminase, such as an APOBEC or an AID deaminase).
• proliferative disease refers to any disease in which cell or tissue homeostasis is disturbed in that a cell or cell population exhibits an abnormally elevated proliferation rate.
• Proliferative diseases include hyperproliferative diseases, such as pre-neoplastic hyperplastic conditions and neoplastic diseases.
• Neoplastic diseases are characterized by an abnormal proliferation of cells and include both benign and malignant neoplasias. Malignant neoplasia is also referred to as cancer.
• protein refers to a polymer of amino acid residues linked together by peptide (amide) bonds.
• the terms refer to a protein, peptide, or polypeptide of any size, structure, or function. Typically, a protein, peptide, or polypeptide will be at least three amino acids long.
• a protein, peptide, or polypeptide may refer to an individual protein or a collection of proteins.
• One or more of the amino acids in a protein, peptide, or polypeptide may be modified, for example, by the addition of a chemical entity such as a carbohydrate group, a hydroxyl group, a phosphate group, a farnesyl group, an isofarnesyl group, a fatty acid group, a linker for conjugation, functionalization, or other modification, etc.
• a protein, peptide, or polypeptide may also be a single molecule or may be a multi-molecular complex.
• a protein, peptide, or polypeptide may be just a fragment of a naturally occurring protein or peptide.
• a protein, peptide, or polypeptide may be naturally occurring, recombinant, or synthetic, or any combination thereof.
• fusion protein refers to a hybrid polypeptide which comprises protein domains from at least two different proteins.
• One protein may be located at the amino-terminal (N-terminal) portion of the fusion protein or at the carboxy-terminal (C- terminal) protein thus forming an "amino-terminal fusion protein” or a "carboxy-terminal fusion protein,” respectively.
• a protein may comprise different domains, for example, a nucleic acid binding domain (e.g., the gRNA binding domain of Cas9 that directs the binding of the protein to a target site) and a nucleic acid cleavage domain or a catalytic domain of a nucleic-acid editing protein.
• a protein comprises a proteinaceous part, e.g., an amino acid sequence constituting a nucleic acid binding domain, and an organic compound, e.g., a compound that can act as a nucleic acid cleavage agent.
• a protein is in a complex with, or is in association with, a nucleic acid, e.g., RNA.
• Any of the proteins provided herein may be produced by any method known in the art.
• the proteins provided herein may be produced via recombinant protein expression and purification, which is especially suited for fusion proteins comprising a peptide linker.
• the term "subject,” as used herein, refers to an individual organism, for example, an individual mammal.
• the subject is a human.
• the subject is a non-human mammal.
• the subject is a non-human primate.
• the subject is a rodent.
• the subject is a sheep, a goat, a cattle, a cat, or a dog.
• the subject is a vertebrate, an amphibian, a reptile, a fish, an insect, a fly, or a nematode.
• the subject is a research animal.
• the subject is genetically engineered, e.g., a genetically engineered non-human subject. The subject may be of either sex and at any stage of development.
• target site refers to a sequence within a nucleic acid molecule that is deaminated by a deaminase or a fusion protein comprising a deaminase, (e.g., a dCas9- deaminase fusion protein provided herein).
• treatment refers to a clinical intervention aimed to reverse, alleviate, delay the onset of, or inhibit the progress of a disease or disorder, or one or more symptoms thereof, as described herein.
• treatment refers to a clinical intervention aimed to reverse, alleviate, delay the onset of, or inhibit the progress of a disease or disorder, or one or more symptoms thereof, as described herein.
• treatment may be administered after one or more symptoms have developed and/or after a disease has been diagnosed.
• treatment may be administered in the absence of symptoms, e.g., to prevent or delay onset of a symptom or inhibit onset or progression of a disease.
• treatment may be administered to a susceptible individual prior to the onset of symptoms (e.g., in light of a history of symptoms and/or in light of genetic or other susceptibility factors). Treatment may also be continued after symptoms have resolved, for example, to prevent or delay their recurrence.
• recombinant protein or nucleic acid molecule comprises an amino acid or nucleotide sequence that comprises at least one, at least two, at least three, at least four, at least five, at least six, or at least seven mutations as compared to any naturally occurring sequence.
• a pharmaceutical composition refers to a composition that can be administrated to a subject in the context of treatment of a disease or disorder.
• a pharmaceutical composition comprises an active ingredient, e.g., a nuclease or a nucleic acid encoding a nuclease, and a pharmaceutically acceptable excipient.
• base editor refers to an agent comprising a polypeptide that is capable of making a modification to a base (e.g., A, T, C, G, or U) within a nucleic acid sequence (e.g., DNA or RNA).
• a base e.g., A, T, C, G, or U
• a nucleic acid sequence e.g., DNA or RNA.
• the base editor is capable of deaminating a base within a nucleic acid.
• the base editor is capable of deaminating a base within a DNA molecule.
• the base editor is capable of deaminating an cytosine (C) in DNA.
• the base editor is a fusion protein comprising a nucleic acid programmable DNA binding protein (napDNAbp) fused to a cytidine deaminase domain.
• the base editor comprises a Cas9 (e.g., dCas9 and nCas9), CasX, CasY, Cpfl, C2cl, C2c2, C2c3, or
• the base editor comprises a Cas9 nickase (nCas9) fused to an cytidine deaminase.
• the base editor comprises a nuclease-inactive Cas9 (dCas9) fused to a cytidine deaminase.
• the base editor is fused to an inhibitor of base excision repair, for example, a UGI domain.
• the base editor comprises a CasX protein fused to a cytidine deaminase.
• the base editor comprises a CasY protein fused to a cytidine deaminase. In some embodiments, the base editor comprises a Cpfl protein fused to a cytidine deaminase. In some embodiments, the base editor comprises a C2cl protein fused to a cytidine deaminase. In some embodiments, the base editor comprises a C2c2 protein fused to a cytidine deaminase. In some embodiments, the base editor comprises a C2c3 protein fused to a cytidine deaminase. In some embodiments, the base editor comprises an Argonaute protein fused to a cytidine deaminase.
• uracil glycosylase inhibitor refers to a protein that is capable of inhibiting a uracil-DNA glycosylase base-excision repair enzyme.
• Cas9 nickase refers to a Cas9 protein that is capable of cleaving only one strand of a duplexed nucleic acid molecule (e.g., a duplexed DNA molecule).
• a Cas9 nickase comprises a D10A mutation and has a histidine at position H840 of SEQ ID NO: 6, or a corresponding mutation in another Cas9 domain, such as any of the Cas9 proteins provided herein.
• a Cas9 nickase may comprise the amino acid sequence as set forth in SEQ ID NO: 8.
• Such a Cas9 nickase has an active HNH nuclease domain and is able to cleave the non-targeted strand of DNA, i.e. , the strand bound by the gRNA. Further, such a Cas9 nickase has an inactive RuvC nuclease domain and is not able to cleave the targeted strand of the DNA, i.e. , the strand where base editing is desired.
• Exemplary Cas9 nickase (Cloning vector pPlatTET-gRNA2; Accession No.
• Some aspects of this disclosure provide fusion proteins that comprise a domain capable of binding to a nucleotide sequence (e.g., a Cas9, or a Cpfl protein) and an enzyme domain, for example, a DNA-editing domain, such as, e.g., a deaminase domain.
• a DNA-editing domain such as, e.g., a deaminase domain.
• the deamination of a nucleobase by a deaminase can lead to a point mutation at the respective residue, which is referred to herein as nucleic acid editing.
• Fusion proteins comprising a Cas9 variant or domain and a DNA editing domain can thus be used for the targeted editing of nucleic acid sequences.
• Such fusion proteins are useful for targeted editing of DNA in vitro, e.g., for the generation of mutant cells or animals; for the introduction of targeted mutations, e.g., for the correction of genetic defects in cells ex vivo, e.g., in cells obtained from a subject that are subsequently re-introduced into the same or another subject; and for the introduction of targeted mutations, e.g., the correction of genetic defects or the introduction of deactivating mutations in disease-associated genes in a subject.
• the Cas9 domain of the fusion proteins described herein does not have any nuclease activity but instead is a Cas9 fragment or a dCas9 protein or domain.
• fusion proteins that comprise (i) a domain capable of binding to a nucleic acid sequence (e.g., a Cas9, or a Cpfl protein); (ii) an enzyme domain, for example, a DNA-editing domain (e.g., a deaminase domain); and (iii) one or more uracil glycosylase inhibitor (UGI) domains.
• a nucleic acid sequence e.g., a Cas9, or a Cpfl protein
• an enzyme domain for example, a DNA-editing domain (e.g., a deaminase domain); and (iii) one or more uracil glycosylase inhibitor (UGI) domains.
• UGI domain e.g., a DNA-editing domain
• UGI uracil glycosylase inhibitor
• nucleic acid programmable DNA binding proteins which may be used to guide a protein, such as a base editor, to a specific nucleic acid ⁇ e.g., DNA or RNA) sequence.
• a protein such as a base editor
• any of the fusion proteins ⁇ e.g., base editors) provided herein may include any nucleic acid programmable DNA binding protein (napDNAbp).
• napDNAbp nucleic acid programmable DNA binding protein
• any of the fusion proteins described herein that include a Cas9 domain can use another napDNAbp, such as CasX, CasY, Cpfl, C2cl, C2c2, C2c3, and Argonaute, in place of the Cas9 domain.
• Nucleic acid programmable DNA binding proteins include, without limitation, Cas9 ⁇ e.g., dCas9 and nCas9), CasX, CasY, Cpfl, C2cl, C2c2, C2C3, and Argonaute.
• Cas9 ⁇ e.g., dCas9 and nCas9
• CasX CasY
• Cpfl C2cl
• Cpfl Clustered Regularly Interspaced Short Palindromic Repeats from Prevotella and Francisella 1
• Cpfl is also a class 2 CRISPR effector. It has been shown that Cpflmediates robust DNA interference with features distinct from Cas9.
• Cpfl is a single RNA-guided endonuclease lacking tracrRNA, and it utilizes a T-rich protospacer-adjacent motif (TTN, TTTN, or YTN). Moreover, Cpfl cleaves DNA via a staggered DNA double- stranded break.
• TTN T-rich protospacer-adjacent motif
• TTTN TTTN
• YTN T-rich protospacer-adjacent motif
• nuclease-inactive Cpfl (dCpfl) variants that may be used as a guide nucleotide sequence-programmable DNA- binding protein domain.
• the Cpfl protein has a RuvC-like endonuclease domain that is similar to the RuvC domain of Cas9 but does not have a HNH endonuclease domain, and the N-terminal of Cpfl does not have the alpha-helical recognition lobe of Cas9.
• the dead Cpfl comprises mutations corresponding to D917A, E1006A, D1255A, D917A/E1006A, D917A/D1255A, E1006A/D1255A, or D917A/E1006A/D1255A in SEQ ID NO: 9. It is to be understood that any mutations, e.g., substitution mutations, deletions, or insertions, that inactivate the RuvC domain of Cpfl, may be used in accordance with the present disclosure.
• the nucleic acid programmable DNA binding protein (napDNAbp) of any of the fusion proteins provided herein is a Cpfl protein.
• the Cpfl protein is a Cpfl nickase (nCpfl).
• the Cpfl protein is a nuclease inactive Cpfl (dCpfl).
• the Cpfl, the nCpfl, or the dCpfl comprises an amino acid sequence that is at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.5% identical to any one of SEQ ID NOs: 9-24.
• the dCpfl comprises an amino acid sequence that is at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.5% identical to any one of SEQ ID NOs: 9-16, and comprises mutations corresponding to D917A, E1006A, D1255A, D917A/E1006A,
• the dCpf 1 protein comprises an amino acid sequence of any one SEQ ID NOs: 9-16. It should be appreciated that Cpfl from other species may also be used in accordance with the present disclosure.
• Wild type Francisella novicida Cpfl (SEQ ID NO: 9) (D917, E1006, and D1255 are bolded and underlined)
• EKFEFNIEDCRKFIDFYKQS IS KHPEWKDFGFRFSDTQRYNS IDEFYRE VENQGYKLTF
• Francisella novicida Cpfl D917A (SEQ ID NO: 10) (A917, E1006, and D1255 are bolded and underlined)
• EKFEFNIEDCRKFIDFYKQS IS KHPEWKDFGFRFSDTQRYNS IDEFYRE VENQGYKLTF ENISESYIDSVVNQGKLYLFQIYNKDFSAYSKGRPNLHTLYWKALFDERNLQDVVYK
• Francisella novicida Cpfl E1006A (SEQ ID NO: 11) (D917, A1006, and D1255 are bolded and underlined)
• EKFEFNIEDCRKFIDFYKQS IS KHPEWKDFGFRFSDTQRYNS IDEFYRE VENQGYKLTF
• Francisella novicida Cpfl D1255A (SEQ ID NO: 12) (D917, E1006, and A1255 are bolded and underlined)
• EKFEFNIEDCRKFIDFYKQS IS KHPEWKDFGFRFSDTQRYNS IDEFYRE VENQGYKLTF
• Francisella novicida Cpfl D917A/E1006A (SEQ ID NO: 13) (A917, A1006, and D1255 are bolded and underlined)
• EKFEFNIEDCRKFIDFYKQS IS KHPEWKDFGFRFSDTQRYNS IDEFYRE VENQGYKLTF
• Francisella novicida Cpfl D917A/D1255A (SEQ ID NO: 14) (A917, E1006, and A1255 are bolded and underlined)
• Francisella novicida Cpfl E1006A/D1255A (SEQ ID NO: 15) (D917, A1006, and A1255 are bolded and underlined)
• EKFEFNIEDCRKFIDFYKQS IS KHPEWKDFGFRFSDTQRYNS IDEFYRE VENQGYKLTF
• Francisella novicida Cpfl D917A/E1006A/D1255A (SEQ ID NO: 16) (A917, A1006, and A 1255 are bolded and underlined)
• EKFEFNIEDCRKFIDFYKQS IS KHPEWKDFGFRFSDTQRYNS IDEFYRE VENQGYKLTF
• the nucleic acid programmable DNA binding protein is a Cpfl protein from an Acidaminococcus species (AsCpfl). Cpfl proteins form
• Acidaminococcus species have been described previously and would be apparent to the skilled artisan.
• Exemplary Acidaminococcus Cpfl proteins include, without limitation, any of the AsCpfl proteins provided herin
• Wild-type AsCpfl- Residue R912 is indicated in bold underlining and residues 661- 667 are indicated in italics and underlining.
• AsCpfl (R912A)- Residue A912 is indicated in bold underlining and residues 661- 667 are indicated in italics and underlining.
• the nucleic acid programmable DNA binding protein is a Cpf 1 protein from a Lachnospiraceae species (LbCpf 1).
• Cpf 1 proteins form Lachnospiraceae species have been described previously have been described previously and would be apparent to the skilled artisan.
• Exemplary Lachnospiraceae Cpfl proteins include, without limitation, any of the LbCpfl proteins provided herein.
• the LbCpfl is a nickase.
• the LbCpfl nickase comprises an R836X mutant relative to SEQ ID NO: 18, wherein X is any amino acid except for R.
• the LbCpfl nickase comprises R836A mutant relative to SEQ ID NO: 18.
• the LbCpfl is a nuclease inactive LbCpfl (dLbCpfl).
• the dLbCpfl comprises a D832X mutant relative to SEQ ID NO: 18, wherein X is any amino acid except for D.
• the dLbCpfl comprises a D832A mutant relative to SEQ ID NO: 18. Additional dCpfl proteins have been described in the art, for example, in Li et al. "Base editing with a Cpfl-cytidine deaminase fusion” Nature Biotechnology; March 2018 DOI: 10.1038/nbt.4102; the entire contents of which are incorporated herein by reference.
• the dCpfl comprises 1, 2, or 3 of the point mutations D832A, E1006A, Dl 125 A of the Cpfl described in Li et al.
• Wild-type LbCpf 1 - Residues R836 and Rl 138 is indicated in bold underlining.
• LbCpfl (R836A)- Residue A836 is indicated in bold underlining.
• the Cpfl protein is a crippled Cpf 1 protein.
• a "crippled Cpfl" protein is a Cpfl protein having diminished nuclease activity as compared to a wild-type Cpfl protein.
• the crippled Cpfl protein preferentially cuts the target strand more efficiently than the non-target strand.
• the Cpfl protein preferentially cuts the strand of a duplexed nucleic acid molecule in which a nucleotide to be edited resides.
• the crippled Cpfl protein preferentially cuts the non- target strand more efficiently than the target strand.
• the crippled Cpfl protein preferentially cuts the target strand of a duplexed nucleic acid molecule in which a nucleotide to be edited does not reside.
• the crippled Cpfl protein preferentially cuts the target strand at least 5% more efficiently than it cuts the non-target strand.
• the crippled Cpfl protein preferentially cuts the target strand at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, 90%, or at least 100% more efficiently than it cuts the non-target strand.
• a crippled Cpfl protein is a non-naturally occurring Cpfl protein.
• the crippled Cpfl protein comprises one or more mutations relative to a wild-type Cpfl protein.
• the crippled Cpfl protein comprises 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 mutations relative to a wild-type Cpfl protein.
• the crippled Cpfl protein comprises an R836A mutation mutation as set forth in SEQ ID NO: 18, or in a corresponding amino acid in another Cpfl protein.
• the crippled Cpfl protein comprises a Rl 138A mutation as set forth in SEQ ID NO: 18, or in a corresponding amino acid in another Cpfl protein.
• the crippled Cpfl protein comprises an R912A mutation mutation as set forth in SEQ ID NO: 17, or in a corresponding amino acid in another Cpfl protein.
• residue R836 of SEQ ID NO: 18 (LbCpf 1) and residue R912 of SEQ ID NO: 17 (AsCpf 1) are examples of corresponding (e.g., homologous) residues.
• a portion of the alignment between SEQ ID NO: 17 and 18 shows that R912 and R836 are corresponding residues.
• any of the Cpfl proteins provided herein comprises one or more amino acid deletions. In some embodiments, any of the Cpfl proteins provided herein comprises 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 amino acid deletions.
• there is a helical region in Cpfl which includes residues 661-667 of AsCpfl (SEQ ID NO: 17), that may obstruct the function of a deaminase (e.g., APOBEC) that is fused to the Cpfl . This region comprises the amino acid sequence KKTGDQK.

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