TY - JOUR T1 - Engineered Cpf1 Enzymes with Altered PAM Specificities JF - bioRxiv DO - 10.1101/091611 SP - 091611 AU - Linyi Gao AU - David B.T. Cox AU - Winston X. Yan AU - John Manteiga AU - Martin Schneider AU - Takashi Yamano AU - Hiroshi Nishimasu AU - Osamu Nureki AU - Feng Zhang Y1 - 2016/01/01 UR - http://biorxiv.org/content/early/2016/12/04/091611.abstract N2 - The RNA-guided endonuclease Cpf1 is a promising tool for genome editing in eukaryotic cells1-5. Compared to other genome editing platforms, Cpf1 offers distinct advantages, such as the ability to easily target multiple genes simultaneously3, as well as low rates of off-target activity4, 5. However, the Acidaminococcus sp. BV3L6 Cpf1 (AsCpf1), which has been successfully harnessed for genome editing, can only robustly cleave target sites preceded by a TTTV protospacer adjacent motif (PAM), which may limit its practical utility. To address this limitation, we used a structure- guided saturation mutagenesis screen to increase the targeting range of Cpf1. We engineered two variants of AsCpf1 with the mutations S542R/K607R and S542R/K548V/N552R that can cleave target sites with TYCV/CCCC and TATV PAMs, respectively, with enhanced activities in vitro and in human cells. Genome-wide assessment of off-target activity indicated that these variants retain a high level of DNA targeting specificity, which can be further improved by introducing mutations in non-PAM-interacting domains. Together, these variants increase the targeting range of AsCpf1 to one cleavage site for every ~8.7 bp in non-repetitive regions of the human genome, providing a useful addition to the CRISPR/Cas genome engineering toolbox. ER -