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.
State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Biomolecules. 2023 Feb 20;13(2):400. doi: 10.3390/biom13020400.
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 (). Although the CRISPR-Cas system-mediated immune defense mechanism has been revealed in , the regulation of gene expression is poorly understood. In this study, we identified a transcription factor, CasR (CRISPR-associated protein repressor, encoded by ), and it could bind to the upstream DNA sequence of the CRISPR-Cas gene cluster and regulate the expression of genes. EMSA and ChIP assays confirmed that CasR could interact with the upstream sequence of the 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 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.
CRISPR-Cas 系统是许多细菌和古菌的一种适应性免疫系统，用于防御外来核酸的入侵，并且该系统在 （）的基因组中保守。虽然 CRISPR-Cas 系统介导的免疫防御机制在 （）中已经被揭示，但对 （）基因表达的调控知之甚少。在本研究中，我们鉴定了一个转录因子 CasR（CRISPR 相关蛋白抑制剂，由 编码），它可以与 CRISPR-Cas 基因簇的上游 DNA 序列结合，并调节 （）基因的表达。EMSA 和 ChIP 实验证实 CasR 可以在体内和体外与 （）启动子的上游序列相互作用。此外，DNA 足迹实验表明 CasR 识别一个 20bp 的回文序列基序，并负调控 （）的表达。综上所述，我们的研究阐明了 CasR 对分枝杆菌中 CRISPR 相关基因表达的调控作用，从而为 CRISPR-Cas 系统的基因表达调控提供了新的见解。
