Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, 28049 Madrid, Spain.
Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, 28049 Madrid, Spain.
DNA Repair (Amst). 2014 Feb;14:1-8. doi: 10.1016/j.dnarep.2013.12.001. Epub 2013 Dec 25.
Bacillus subtilis cells respond to double strand breaks (DSBs) with an ordered recruitment of repair proteins to the site lesion, being RecN one of the first responders. In B. subtilis, one of the responses to DSBs is to increase RecN expression rather than modifying its turnover rate. End-processing activities and the RecA protein itself contribute to increase RecN levels after DNA DSBs. RecO is required for RecA filament formation and full SOS induction, but its absence did not significantly affect RecN expression. Neither the absence of LexA nor the phosphorylation state of RecA or SsbA significantly affect RecN expression levels. These findings identify two major mechanisms (SOS and DSB response) used to respond to DSBs, with LexA required for one of them (SOS response). The DSB response, which requires end-processing and RecA or short RecO-independent RecA filaments, highlights the importance of guarding genome stability by modulating the DNA damage responses.
枯草芽孢杆菌细胞通过将修复蛋白有序地招募到损伤部位来应对双链断裂（DSBs），其中 RecN 是最早的响应者之一。在枯草芽孢杆菌中，应对 DSB 的一种反应是增加 RecN 的表达，而不是改变其周转率。末端处理活性和 RecA 蛋白本身有助于在 DNA DSB 后增加 RecN 水平。RecO 是 RecA 丝形成和完全 SOS 诱导所必需的，但它的缺失并没有显著影响 RecN 的表达。LexA 的缺失或 RecA 或 SsbA 的磷酸化状态均不会显著影响 RecN 的表达水平。这些发现确定了两种主要的机制（SOS 和 DSB 反应）用于应对 DSB，其中 LexA 是其中一种机制（SOS 反应）所必需的。DSB 反应需要末端处理和 RecA 或短的独立于 RecO 的 RecA 丝，这凸显了通过调节 DNA 损伤反应来保护基因组稳定性的重要性。
