Liu Xingchao, Sun Meng, Cheng Yaqing, Yang Renjun, Wen Ying, Chen Zhi, Li Jilun
State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
Microbiology (Reading). 2016 Apr;162(4):707-716. doi: 10.1099/mic.0.000251. Epub 2016 Feb 2.
The role of the HO-sensing transcriptional regulator OxyR in oxidative stress responses in was investigated. An deletion mutant was more sensitive to HO and -butyl hydroperoxide than was the WT strain, indicating that OxyR mediates the defensive system against HO and organic peroxide. Evidence presented herein suggests that in cells treated with exogenous HO, the oxidized form of OxyR activated expression of by binding to a palindromic sequence of the promoter region. Oxidized OxyR also induced expression of other antioxidant enzymes (KatA1, KatA2, KatA3 and OhrB1) and oxidative stress regulators (CatR, OhrR and σ). The thiol-oxidative stress regulator gene was regulated at the transcription level by OxyR. We conclude that OxyR is necessary to activate transcription of from the σ-dependent promoter to express an unstable larger isoform of σ during oxidative stress. In response to oxidative stress, OxyR facilitates rapid production of HO-scavenging enzymes to repair oxidative damage through direct regulation and cascaded regulation of CatR, OhrR and σ.
研究了HO感应转录调节因子OxyR在[具体生物名称未给出]氧化应激反应中的作用。一个[具体基因名称未给出]缺失突变体比野生型菌株对HO和叔丁基过氧化氢更敏感，表明OxyR介导了针对HO和有机过氧化物的防御系统。本文提供的证据表明，在用外源性HO处理的细胞中，OxyR的氧化形式通过与启动子区域的回文序列结合来激活[具体基因名称未给出]的表达。氧化的OxyR还诱导了其他抗氧化酶（KatA1、KatA2、KatA3和OhrB1）以及氧化应激调节因子（CatR、OhrR和σ） 的表达。硫醇氧化应激调节基因[具体基因名称未给出]在转录水平上受OxyR调控。我们得出结论，在氧化应激期间，OxyR对于从σ依赖性启动子激活[具体基因名称未给出]的转录以表达不稳定的较大异构体σ是必要的。响应氧化应激时，OxyR通过对CatR、OhrR和σ的直接调节和级联调节，促进HO清除酶的快速产生以修复氧化损伤。
