Transcription modulation in animals using CRISPR/Cas systems
Non-human animal cells and non-human animals comprising CRISPR/Cas synergistic activation mediator system components and methods of making and using such non-human animal cells and non-human animals are provided. Methods are provided for using such non-human animals to increase expression of target genes in vivo and to assess CRISPR/Cas synergistic activation mediator systems for the ability to increase expression of target genes in vivo.
1. A method for increasing expression of a target gene in vivo in a non-human animal, comprising introducing into the non-human animal one or more guide RNAs,
wherein the non-human animal comprises a genomically integrated expression cassette, wherein the expression cassette comprises:
(a) a nucleic acid encoding a chimeric Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) associated (Cas) protein comprising a nuclease-inactive Cas protein fused to one or more transcriptional activation domains; and
(b) a nucleic acid encoding a chimeric adaptor protein comprising an adaptor fused to one or more transcriptional activation domains,
wherein the expression cassette further comprises a polyadenylation signal or transcription terminator upstream of the nucleic acid encoding the chimeric Cas protein,
wherein the polyadenylation signal or transcription terminator is flanked by recombinase recognition sites recognized by a site-specific recombinase,
wherein the expression cassette comprises the sequence set forth in SEQ ID NO: 31,
wherein the polyadenylation signal or transcription terminator has been excised in a tissue in the non-human animal,
wherein the one or more guide RNAs each comprise one or more adaptor-binding elements to which the chimeric adaptor protein can specifically bind,
wherein the one or more guide RNAs are introduced by viral delivery, and
wherein the one or more guide RNAs form complexes with the chimeric Cas protein and chimeric adaptor protein and guide them to a target sequence within the target gene, thereby increasing expression of the target gene.
2. The method of claim 1 , wherein the one or more guide RNAs are introduced via adeno-associated virus (AAV)-mediated delivery.
3. The method of claim 2 , wherein the AAV is AAV8.
4. The method of claim 1 , wherein the target gene is a gene expressed in the liver.
5. The method of claim 1 , wherein the target sequence comprises a regulatory sequence within the target gene, and wherein the regulatory sequence comprises a promoter or an enhancer.
6. The method of claim 1 , wherein the target sequence is within 200 base pairs of the transcription start site of the target gene, or wherein the target sequence is within the region 200 base pairs upstream of the transcription start site and 1 base pair downstream of the transcription start site.
7. The method of claim 1 , wherein the one or more guide RNAs are introduced in the form of RNA.
8. The method of claim 1 , wherein the one or more guide RNAs are introduced in the form of DNA.
9. The method of claim 8 , wherein each of the one or more guide RNAs is operably linked to a different U6 promoter.
10. The method of claim 1 , wherein each of the one or guide RNAs comprises two adaptor-binding elements to which the chimeric adaptor protein can specifically bind, and wherein a first adaptor-binding element is within a first loop of each of the one or more guide RNAs, and a second adaptor-binding element is within a second loop of each of the one or more guide RNAs.
11. The method of claim 10 , wherein each of one or more guide RNAs is a single guide RNA comprising a CRISPR RNA (crRNA) portion fused to a transactivating CRISPR RNA (tracrRNA) portion, and
wherein the first loop is the tetraloop corresponding to residues 13-16 of SEQ ID NO: 12 and the second loop is the stem loop 2 corresponding to residues 53-56 of SEQ ID NO: 12.
12. The method of claim 1 , wherein the adaptor-binding element comprises the sequence set forth in SEQ ID NO: 16, or wherein each of the one or more guide RNAs comprises the sequence set forth in SEQ ID NO: 40 or 63.
13. The method of claim 1 , wherein at least one of the one or more guide RNAs targets a disease-associated gene.
14. The method of claim 13 , wherein the disease-associated gene is a Ttr gene, and wherein the Ttr-targeting guide RNA targets a sequence comprising the sequence set forth in any one of SEQ ID NOS: 34-36 or wherein the Ttr-targeting guide RNA comprises the sequence set forth in any one of SEQ ID NOS: 37-39.
15. The method of claim 1 , wherein at least one of the one or more guide RNAs targets a Pcsk9 gene, and wherein the Pcsk9-targeting guide RNA targets a sequence comprising the sequence set forth in any one of SEQ ID NOS: 89-91 or wherein the Pcsk9-targeting guide RNA comprises the sequence set forth in any one of SEQ ID NOS: 92-94, and wherein the method causes hypercholesterolemia in the non-human animal.
16. The method of claim 1 , wherein at least one of the one or more guide RNAs targets a Ldlr gene, and wherein the Ldlr-targeting guide RNA targets a sequence comprising the sequence set forth in any one of SEQ ID NOS: 75-77 or wherein the Ldlr-targeting guide RNA comprises the sequence set forth in any one of SEQ ID NOS: 78-80.
17. The method of claim 1 , wherein the one or more guide RNAs target two or more target genes, or wherein the one or more guide RNAs comprise multiple guide RNAs that target a single target gene.
18. The method of claim 17 , wherein the one or more guide RNAs comprise at least three guide RNAs that target a single target gene.
19. The method of claim 18 , wherein:
(a) the at least three guide RNAs target the mouse Ttr locus, and wherein a first guide RNA targets a sequence comprising SEQ ID NO: 34 or comprises the sequence set forth in SEQ ID NO: 37, a second guide RNA targets a sequence comprising SEQ ID NO: 35 or comprises the sequence set forth in SEQ ID NO: 38, and a third guide RNA targets a sequence comprising SEQ ID NO: 36 or comprises the sequence set forth in SEQ ID NO: 39;
(b) the at least three guide RNAs target the mouse Pcsk9 locus, and wherein a first guide RNA targets a sequence comprising SEQ ID NO: 89 or comprises the sequence set forth in SEQ ID NO: 92, a second guide RNA targets a sequence comprising SEQ ID NO: 90 or comprises the sequence set forth in SEQ ID NO: 93, and a third guide RNA targets a sequence comprising SEQ ID NO: 91 or comprises the sequence set forth in SEQ ID NO: 94; or
(c) the at least three guide RNAs target the mouse Ldlr locus, and wherein a first guide RNA targets a sequence comprising SEQ ID NO: 75 or comprises the sequence set forth in SEQ ID NO: 78, a second guide RNA targets a sequence comprising SEQ ID NO: 76 or comprises the sequence set forth in SEQ ID NO: 79, and a third guide RNA targets a sequence comprising SEQ ID NO: 77 or comprises the sequence set forth in SEQ ID NO: 80.
20. The method of claim 1 , wherein the increase in expression of the target gene is at least 0.5-fold, 1-fold, 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, or 20-fold higher relative to a control non-human animal.
21. The method of claim 1 ,
wherein the non-human animal further comprises a genomically integrated Cre recombinase expression cassette comprising a Cre recombinase coding sequence operably linked to a tissue-specific promoter, and the polyadenylation signal or transcription terminator has been excised in a tissue-specific manner, or wherein the method further comprises introducing the Cre recombinase into the non-human animal.
22. The method of claim 21 , wherein the Cre recombinase is introduced via adeno-associated virus (AAV)-mediated delivery, AAV8-mediated delivery, lipid-nanoparticle-mediated delivery, or hydrodynamic delivery.
23. The method of claim 21 , wherein the Cre recombinase is introduced or expressed in a tissue-specific manner or a liver-specific manner.
24. The method of claim 21 , wherein the Cre recombinase is introduced in the form of protein.
25. The method of claim 21 , wherein the Cre recombinase is introduced in the form of DNA or RNA.
26. The method of claim 25 , wherein the Cre recombinase is introduced in the form of DNA operably linked to an albumin promoter, or wherein the non-human animal comprises the genomically integrated Cre recombinase expression cassette comprising the Cre recombinase coding sequence operably linked to the tissue-specific promoter, wherein the tissue-specific promoter is an albumin promoter.
27. The method of claim 1 , wherein the one or more guide RNAs are introduced via adeno-associated virus (AAV)-mediated delivery, wherein each of the one or more guide RNAs is operably linked to a different U6 promoter, and wherein the one or more guide RNAs comprise multiple guide RNAs that target a single target gene.
28. The method of claim 1 , wherein the genomically integrated expression cassette is integrated into a safe harbor locus, and wherein the first expression cassette is operably linked to an endogenous promoter in the safe harbor locus.
29. The method of claim 28 , wherein the safe harbor locus is a Rosa26 locus.
30. The method of claim 1 , wherein the non-human animal is a mammal.
31. The method of claim 30 , wherein the mammal is a rodent that is a rat or a mouse.
32. The method of claim 31 , wherein the rodent is the mouse.
33. The method of claim 1 , wherein the one or more guide RNAs are introduced via lentivirus-mediated delivery.
34. The method of claim 1 , wherein the one or more guide RNAs are introduced into the non-human animal by intravenous injection.
35. The method of claim 1 , wherein the one or more guide RNAs are introduced into the non-human animal by intrathecal, intracerebroventricular, intraparenchymal, intraocular, intraorbital, subconjuctival, intravitreal, subretinal, or transscleral injection.