Cooperating with Chuan He and Puping Liang, our lab published an article, which is entitled “Systematic identification of CRISPR off-target effects by CROss-seq”, in Protein & Cell on July 15th. Yan Li is the co-first author. Hong-Xuan Chen and Dong-Zhao Ma also made great contribution to this work. Congratulations to them!

The CRISPR-mediated genome editing tools have been extensively applied in basic and clinical researches. Comprehensively and accurately evaluating the off-target effects of CRISPR editing tools is a hot and difficult point in the field of gene editing. In this study, we developed a general, efficient and scalable off-target detection method, CROss-seq (CRISPR Off-targeting ssDNA sequencing). This method takes advantage of that in CRISPR-mediated genome editors, the RNA-guided site-specific DNA recognition will form an R-loop structure and expose the opposite ssDNA. By detecting the ssDNA component of R-loop induced by targeted recognition, we can know the binding events of CRISPR-mediated genome editors. This study comprehensively and systematically evaluated the targeting specificity of Cas9, BE (CBE and ABE) and PE in vitro and in vivo by CROss-seq. We believe that CROss-seq can help better evaluate the off-target effect of CRISPR-mediated genome editing tools currently available and possible in the future, and provide methodological innovation for promoting the wide application of CRISPR editing tools in basic research and gene therapy.

By Zhihao Zhang