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Enhancing specificity of RNA-guided clustered, regularly interspaced short palindromic repeats (CRISPR)-based genome editing with paired guide RNAs

Enhancing the specificity of CRISPR-based genome editing systems could improve its use in therapeutic applications. CRISPR systems use small guide RNAs that pair with a target DNA sequence and the CRISPR-associated protein 9 (Cas9) to excise target DNA. To improve specificity, a system was designed that uses a Cas9 mutant enzyme plus a pair of guide RNAs to excise a targeted DNA sequence. In cell lines, this CRISPR-based editing system decreased off-target DNA excision by 50- to 1,000-fold compared with systems that use single guide RNAs. Next steps include whole-genome sequencing studies to better characterize the specificity of the Cas9 mutant and further improving the efficiency of the system (see Crisper results for CRISPR, page 9).

SciBX 6(35); doi:10.1038/scibx.2013.978
Published online Sept. 12, 2013

Patent application filed; available for licensing from the Broad Institute of MIT and Harvard Office of Strategic Alliances and Partnering

Ran, F.A. et al. Cell; published online
Aug. 29, 2013;
doi:10.1016/j.cell.2013.08.021
Contact: Feng Zhang, Broad Institute of MIT and Harvard, Cambridge, Mass.
e-mail:
zhang@broadinstitute.org