TY - JOUR T1 - Suppression of unwanted CRISPR/Cas9 editing by co-administration of catalytically inactivating truncated guide RNAs JF - bioRxiv DO - 10.1101/597849 SP - 597849 AU - John C. Rose AU - Nicholas A. Popp AU - Christopher D. Richardson AU - Jason J. Stephany AU - Julie Mathieu AU - Cindy T. Wei AU - Jacob E. Corn AU - Dustin J. Maly AU - Douglas M. Fowler Y1 - 2019/01/01 UR - http://biorxiv.org/content/early/2019/04/03/597849.abstract N2 - CRISPR/Cas9 nucleases are powerful genome engineering tools, but unwanted cleavage at off-target and previously edited sites remains a major concern. Numerous strategies to reduce unwanted cleavage have been devised, but all are imperfect. Here, we report off-target sites can be shielded from the active Cas9•single guide RNA (sgRNA) complex through the co-administration of dead-RNAs (dRNAs), truncated guide RNAs that direct Cas9 binding but not cleavage. dRNAs can effectively suppress a wide-range of off-targets with minimal optimization while preserving on-target editing, and they can be multiplexed to suppress several off-targets simultaneously. dRNAs can be combined with high-specificity Cas9 variants, which often do not eliminate all unwanted editing. Moreover, dRNAs can prevent cleavage of homology-directed repair (HDR)-corrected sites, facilitating “scarless” editing by eliminating the need for blocking mutations. Thus, we enable precise genome editing by establishing a novel and flexible approach for suppressing unwanted editing of both off-targets and HDR-corrected sites. ER -