Genomewide unbiased identification of DSBs evaluated by sequencing (GUIDE-seq)
Unbiased, genomewide and highly sensitive methods for detecting mutations, e.g., off-target mutations, induced by engineered nucleases.
1. A method for detecting double stranded breaks (DSBs) in genomic DNA (gDNA) of a cell, the method comprising:
contacting the cell with a blunt-ended double-stranded oligodeoxynucleotide (dsODN), wherein both strands of the dsODN are orthogonal to the genome of the cell, and further wherein (a) the 5′ ends of the dsODN are phosphorylated, and (b) phosphorothioate linkages are present on both 3′ ends, or phosphorothioate linkages are present on both 3′ ends and both 5′ ends;
maintaining the cell under conditions sufficient for the cell to repair the DSBs, integrating a dsODN at one or more DSBs;
amplifying a portion of gDNA comprising an integrated dsODN; and
sequencing the amplified portion of the gDNA,
thereby detecting a DSB in the gDNA of the cell.
2. The method of claim 1 , wherein amplifying a portion of the gDNA comprises:
fragmenting the gDNA;
ligating ends of the fragmented gDNA from the cell with a universal adapter; and performing polymerase chain reaction (PCR) on the ligated DNA.
3. The method of claim 1 , wherein the cell is a mammalian cell.
4. The method of claim 1 , wherein the dsODN is 30-35 nts long.
5. The method of claim 1 , wherein the dsODN is phosphorylated on the 5′ ends, and phosphorothioated on the 3′ ends.
6. The method of claim 1 , wherein the dsODN contains a randomized DNA barcode.
7. The method claim 1 , comprising:
shearing the gDNA into fragments; and
preparing the fragments for sequencing by end-repair, a-tailing, and ligation of a single-tailed sequencing adapter.
8. The method of claim 1 , wherein the dsODN is 15-50 nts long.
9. A method for detecting double stranded breaks (DSBs) in gDNA of a cell, the method comprising:
contacting the cell with a blunt-ended double-stranded oligodeoxynucleotide (dsODN), wherein both strands of the dsODN are orthogonal to the genome of the cell, and further wherein (a) the 5′ ends of the dsODN are phosphorylated, and (b) phosphorothioate linkages are present on both 3′ ends, or phosphorothioate linkages are present on both 3′ ends and both 5′ ends;
maintaining the cell under conditions sufficient for the DSBs to occur in the genomic DNA of the cell, and for the cell to repair the DSBs, integrating a dsODN at one or more DSBs;
amplifying a portion of gDNA comprising an integrated dsODN; and
sequencing the amplified portion of the genomic DNA,
thereby detecting a DSB in the gDNA of the cell.
10. The method of claim 9 , wherein amplifying a portion of the gDNA comprises:
fragmenting the gDNA;
ligating ends of the fragmented gDNA from the cell with a universal adapter; and performing PCR on the ligated DNA.
11. The method of claim 9 , wherein the cell is a mammalian cell.
12. The method of claim 9 , wherein the dsODN is 30-35 nts long.
13. The method of claim 9 , wherein the dsODN is 15-50 nts long.
14. The method of claim 9 , wherein the dsODN is phosphorylated on the 5′ ends, and phosphorothioated on the 3′ ends.
15. The method of claim 9 , wherein the dsODN contains a randomized DNA barcode.
16. The method claim 9 , comprising:
shearing the gDNA into fragments; and
preparing the fragments for sequencing by end-repair, a-tailing, and ligation of a single-tailed sequencing adapter.