Engineering of near-PAMless adenine base editor with enhanced editing activity and reduced off-target

作者：Cao, Xiaofang; Guo, Junfan; Huang, Shisheng; Yu, Wenxia; Li, Guanglei; An, Lisha; Li, Xiangyang; Tao, Wanyu; Liu, Qing; Huang, Xingxu; Jin, Xiaohua^*; Ma, Xu^*

来源：Molecular Therapy-Nucleic Acids, 2022, 28: 732-742.

DOI：10.1016/j.omtn.2022.04.032

• CLINVAR PUBLIC ARCHIVE
• GENOMIC DNA

About 47% of pathogenic point mutations could be corrected by ABE-induced A.T-to-G.C conversions. However, the applications of ABEs are still hindered by undesired editing efficiency, limited editing scopes, and off-targeting effects. Here, we develop a new adenine base editor, by embedding TadA-8e monomer into SpRY-nCas9, named as CE-8e-SpRY, which exhibits higher activity at NRN than NYN PAMs favored by SpRY nuclease. CE-8e-SpRY could target nearly all genomic sites in principle and induces the highest targeting efficiency among tested SpRY-based ABEs. In addition, CE-8e-SpRY also shows reduced RNA and DNA off-targeting activities. With optimized sgRNAs, CE-8e-SpRY induces efficient or desired target editing at some disease-relevant loci where conventional ABEs were unable to induce precise and satisfied editing. Taken together, our CE-8e-SpRY could broaden the applicability of ABEs in correcting or introducing pathogenic point mutations.

• 单位
  中国科学院研究生院; 中国医学科学院; 中国医学科学院北京协和医院; 南方医科大学