Engineered minimal type I CRISPR-Cas system for transcriptional activation and base editing in human cells
Jing Guo, Luyao Gong, Haiying Yu, Ming Li, Qiaohui An, Zhenquan Liu, Shuru Fan, Changjialian Yang, Dahe Zhao, Jing Han, Hua Xiang
Abstract
Type I CRISPR-Cas systems are widespread and have exhibited high versatility and efficiency in genome editing and gene regulation in prokaryotes. However, due to the multi-subunit composition and large size, their application in eukaryotes has not been thoroughly investigated. Here, we demonstrate that the type I-F2 Cascade, the most compact among type I systems, with a total gene size smaller than that of SpCas9, can be developed for transcriptional activation in human cells. The efficiency of the engineered I-F2 tool can match or surpass that of dCas9. Additionally, we create a base editor using the I-F2 Cascade, which induces a considerably wide editing window (~30 nt) with a bimodal distribution. It can expand targetable sites, which is useful for disrupting functional sequences and genetic screening. This research underscores the application of compact type I systems in eukaryotes, particularly in the development of a base editor with a wide editing window. Type I CRISPR-Cas systems are widely distributed in prokaryotes but have long been overlooked for applications in eukaryotes. Here, authors develop transcriptional activators and base editors with wide editing windows (~30 nt) in human cells using compact type I-F2 Cascades