Using truncated guide RNAs (tru-gRNAs) to increase specificity for RNA-guided genome editing

1. A method of increasing specificity of Streptococcus pyogenes CRISPR/Cas9 (Cas9) RNA-guided genome editing in a cell, the method comprising contacting the cell with a guide RNA that includes a complementarity region at the 5′ end of the guide RNA consisting of 17-18 nucleotides that are complementary to 17-18 consecutive nucleotides of the complementary strand of a selected target genomic sequence, wherein the target sequence is immediately 5′ of a protospacer adjacent motif (PAM), and wherein the guide RNA is

(i) a single guide RNA that includes at the 5′ end of the single guide RNA a complementarity region consisting of 17-18 nucleotides that are complementary to 17-18 consecutive nucleotides of the complementary strand of the selected target genomic sequence on a double-stranded DNA molecule, or

(ii) a crRNA that includes at the 5′ end of the crRNA a complementarity region consisting of 17-18 nucleotides that are complementary to 17-18 consecutive nucleotides of the complementary strand of the selected target genomic sequence, and a tracrRNA,

wherein in the presence of a S. pyogenes Cas9 genome editing enzyme, the guide RNA complementarity region binds and directs the Cas9 genome editing enzyme to the target genomic sequence, thereby increasing specificity of RNA-guided genome editing in a cell.

2. The method of claim 1 , wherein the crRNA is SEQ ID NO: 2407 and the tracrRNA is SEQ ID NO: 8; the crRNA is SEQ ID NO: 2404 and the tracrRNA is SEQ ID NO: 2405; or the crRNA is SEQ ID NO: 2408 and the tracrRNA is SEQ ID NO: 2406.

3. The method of claim 1 , wherein the tracrRNA is selected from the group consisting of SEQ ID NO: 8, SEQ ID NO: 2405, SEQ ID NO: 2406, SEQ ID NO: 2409, SEQ ID NO: 2410, SEQ ID NO: 2411 and SEQ ID NO: 2412.

4. The method of claim 1 , wherein the guide RNA is (i) the single guide RNA that includes at the 5′ end of the single RNA the complementarity region consisting of 17-18 nucleotides that are complementary to 17-18 consecutive nucleotides of the complementary strand of the selected target genomic sequence.

5. The method of claim 1 , wherein the guide RNA is a ribonucleic acid selected from the group consisting of: SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 2404, SEQ ID NO: 2407 and SEQ ID NO: 2408.

6. The method of claim 1 , wherein the complementarity region is complementary to 17 consecutive nucleotides of the complementary strand of the selected target genomic sequence.

7. The method of claim 1 , wherein the complementarity region is complementary to 18 consecutive nucleotides of the complementary strand of the selected target genomic sequence.

8. The method of claim 1 , wherein the cell is a eukaryotic cell.

9. A method of inducing a break in a target region of a double-stranded DNA molecule in a cell, the method comprising expressing in or introducing into the cell:

a S. pyogenes CRISPR/Cas9 nuclease or nickase; and

a guide RNA that includes a complementarity region at the 5′ end of the guide RNA consisting of 17-18 nucleotides that are complementary to 17-18 consecutive nucleotides of the complementary strand of a double-stranded DNA molecule, wherein the target region sequence is immediately 5′ of a protospacer adjacent motif (PAM), and wherein the guide RNA complementarity region binds and directs the Cas9 nuclease or nickase to the target region sequence of a double-stranded DNA molecule, and wherein the guide RNA is

(i) a single guide RNA that includes at the 5′ end of the single guide RNA a complementarity region consisting of 17-18 nucleotides that are complementary to 17-18 consecutive nucleotides of the complementary strand of a selected target genomic sequence on a double stranded DNA molecule, or

(ii) a crRNA that includes at the 5′ end of the crRNA a complementarity region consisting of 17-18 nucleotides that are complementary to 17-18 consecutive nucleotides of the complementary strand of a selected target genomic sequence, and a tracrRNA; thereby inducing a break in the target region of a double-stranded DNA molecule in a cell.

10. The method of claim 9 , wherein the guide RNA comprises a ribonucleic acid selected from the group consisting of: SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 2404, SEQ ID NO: 2407 and SEQ ID NO: 2408.

11. The method of claim 9 , wherein the complementarity region is complementary to 17 consecutive nucleotides of the complementary strand of the selected target region of a double-stranded DNA molecule.

12. The method of claim 9 , wherein the complementarity region is complementary to 18 consecutive nucleotides of the complementary strand of a selected target region of the double-stranded DNA molecule.

13. The method of claim 9 , wherein the target region is in a target genomic sequence.

14. The method of claim 9 , wherein the cell is a eukaryotic cell.

15. The method of claim 9 , wherein the crRNA is SEQ ID NO: 2407 and the tracrRNA is SEQ ID NO: 8; the crRNA is SEQ ID NO: 2404 and the tracrRNA is SEQ ID NO: 2405; or the mRNA is SEQ ID NO: 2408 and the tracrRNA is SEQ ID NO: 2406.

16. The method of claim 9 , wherein the tracrRNA is selected from the group consisting of SEQ ID NO: 8, SEQ ID NO: 2405, SEQ ID NO: 2406, SEQ ID NO: 2409, SEQ ID NO: 2410, SEQ ID NO: 2411 and SEQ ID NO: 2412.

17. A method of modifying a target region of a double-stranded DNA molecule in a cell, the method comprising expressing in or introducing into the cell:

a S. pyogenes CRISPR dCas9-heterologous functional domain fusion protein (dCas9-HFD); and a guide RNA that includes a complementarity region at the 5′ end of the guide RNA consisting of 17-18 nucleotides that are complementary to 17-18 consecutive nucleotides of the complementary strand of a selected target sequence present on a double-stranded DNA molecule, wherein the target sequence is immediately 5′ of a protospacer adjacent motif (PAM), and wherein the guide RNA is:

(i) a single guide RNA that includes a complementarity region at the 5′ end of the single guide RNA consisting of 17-18 nucleotides that are complementary to 17-18 consecutive nucleotides of the complementary strand of a selected target genomic sequence on a double stranded DNA molecule, or

(ii) a crRNA that includes at the 5′ end of the crRNA a complementarity region consisting of 17-18 nucleotides that are complementary to 17-18 consecutive nucleotides of the complementary strand of a selected target genomic sequence, and a tracrRNA, and

wherein the guide RNA complementarity region binds and directs the dCas9-HFD to the target region of the double-stranded DNA molecule, thereby modifying the target region of a double-stranded DNA molecule in a cell.