Highly efficient base editing in Staphylococcus aureus using an engineered CRISPR RNA-guided cytidine deaminase

Tongnian Gu; Siqi Zhao; Yishuang Pi; Weizhong Chen; Chuanyuan Chen; Qian Liu; Min Li; Dali Han; Quanjiang Ji

doi:10.1039/c8sc00637g

Highly efficient base editing in Staphylococcus aureus using an engineered CRISPR RNA-guided cytidine deaminase

Chem Sci. 2018 Feb 22;9(12):3248-3253. doi: 10.1039/c8sc00637g. eCollection 2018 Mar 28.

Authors

Tongnian Gu¹, Siqi Zhao^{2

3}, Yishuang Pi¹, Weizhong Chen¹, Chuanyuan Chen^{2

3}, Qian Liu⁴, Min Li⁴, Dali Han^{2

3}, Quanjiang Ji¹

Affiliations

¹ School of Physical Science and Technology , ShanghaiTech University , Shanghai 201210 , China . Email: quanjiangji@shanghaitech.edu.cn.
² Key Laboratory of Genomic and Precision Medicine , Beijing Institute of Genomics , Chinese Academy of Sciences , Beijing 100101 , China . Email: handl@big.ac.cn.
³ College of Future Technology , Sino-Danish College , University of Chinese Academy of Science , Beijing 100049 , China.
⁴ Department of Laboratory Medicine , Ren Ji Hospital , School of Medicine , Shanghai Jiao Tong University , Shanghai 200127 , China.

Abstract

Novel therapeutic means against Staphylococcus aureus infections are urgently needed due to the emergence of drug-resistant S. aureus. We report the development of a CRISPR RNA-guided cytidine deaminase (pnCasSA-BEC), enabling highly efficient gene inactivation and point mutations in S. aureus. We engineered a fusion of a Cas9 nickase (Cas9D10A) and a cytidine deaminase (APOBEC1) that can be guided to a target genomic locus for gene inactivation via generating a premature stop codon. The pnCasSA-BEC system nicks the non-edited strand of the genomic DNA, directly catalyzes the conversion of cytidine (C) to uridine (U), and relies on DNA replication to achieve C → T (G → A) conversion without using donor repair templates. The development of the base-editing system will dramatically accelerate drug-target exploration in S. aureus and provides critical insights into the development of base-editing tools in other microbes.