Regulation of CRISPR-Associated Genes by Rv1776c (CasR) in <i>Mycobacterium tuberculosis</i>
Wenping Wei,
Xiaofang Jiang,
Li Zhang,
Yunjun Yan,
Jinyong Yan,
Li Xu,
Chun-Hui Gao,
Min Yang
Affiliations
Wenping Wei
Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
Xiaofang Jiang
State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
Li Zhang
State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
Yunjun Yan
Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
Jinyong Yan
Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
Li Xu
Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
Chun-Hui Gao
State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
Min Yang
Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
The CRISPR-Cas system is an adaptive immune system for many bacteria and archaea to defend against foreign nucleic acid invasion, and this system is conserved in the genome of M. tuberculosis (Mtb). Although the CRISPR-Cas system-mediated immune defense mechanism has been revealed in Mtb, the regulation of cas gene expression is poorly understood. In this study, we identified a transcription factor, CasR (CRISPR-associated protein repressor, encoded by Rv1776c), and it could bind to the upstream DNA sequence of the CRISPR-Cas gene cluster and regulate the expression of cas genes. EMSA and ChIP assays confirmed that CasR could interact with the upstream sequence of the csm6 promoter, both in vivo and in vitro. Furthermore, DNA footprinting assay revealed that CasR recognized a 20 bp palindromic sequence motif and negatively regulated the expression of csm6. In conclusion, our research elucidates the regulatory effect of CasR on the expression of CRISPR-associated genes in mycobacteria, thus providing insight into gene expression regulation of the CRISPR-Cas system.
