National Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Nucleic Acids Res. 2012 Feb;40(3):1009-20. doi: 10.1093/nar/gkr830. Epub 2011 Oct 5.
Transcriptional regulation plays a critical role in the life cycle of Mycobacterium smegmatis and its related species, M. tuberculosis, the causative microbe for tuberculosis. However, the key transcriptional factors involved in broad regulation of diverse genes remain to be characterized in mycobacteria. In the present study, a TetR-like family transcriptional factor, Ms6564, was characterized in M. smegmatis as a master regulator. A conserved 19 bp-palindromic motif was identified for Ms6564 binding using DNaseI footprinting and EMSA. A total of 339 potential target genes for Ms6564 were further characterized by searching the M. smegmatis genome based on the sequence motif. Notably, Ms6564 bound with the promoters of 37 cell cycle and DNA damage/repair genes and regulated positively their expressions. The Ms6564-overexpressed recombinant strain yielded 5-fold lower mutation rates and mutation frequencies, whereas deletion of Ms6564 resulted in ∼5-fold higher mutation rates for the mutant strain compared with the wild-type strain. These findings suggested that Ms6564 may function as a global regulator and might be a sensor necessary for activation of DNA damage/repair genes.
转录调控在分枝杆菌属及其相关物种（结核分枝杆菌，导致结核病的微生物）的生命周期中起着关键作用。然而，分枝杆菌中广泛调节多种基因的关键转录因子仍有待鉴定。在本研究中，鉴定了分枝杆菌中的一个 TetR 样家族转录因子 Ms6564，作为一个主要调控因子。通过 DNaseI 足迹法和 EMSA 鉴定了用于 Ms6564 结合的保守的 19 个碱基对回文基序。根据序列基序，进一步通过搜索分枝杆菌基因组，鉴定了总共 339 个潜在的 Ms6564 靶基因。值得注意的是，Ms6564 与 37 个细胞周期和 DNA 损伤/修复基因的启动子结合，并正向调节它们的表达。与野生型菌株相比，Ms6564 过表达重组菌株的突变率和突变频率降低了 5 倍，而 Ms6564 缺失导致突变株的突变率增加了约 5 倍。这些发现表明 Ms6564 可能作为一个全局调控因子发挥作用，并且可能是激活 DNA 损伤/修复基因所必需的传感器。
