Mfd protects against oxidative stress in Bacillus subtilis independently of its canonical function in DNA repair
Mfd protects against oxidative stress in Bacillus subtilis independently of its canonical function in DNA repair
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DOI：
10.1186/s12866-019-1394-x
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发表时间：
2019-01-28
期刊：
影响因子：
4.2
通讯作者：
Robleto, Eduardo A.
中科院分区：
文献类型：
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作者：
Martin, Holly Anne;Porter, Katelyn E.;Robleto, Eduardo A.
背景研究表明，在营养限制条件下，枯草芽孢杆菌的诱变依赖于Mfd。Mfd启动一种类型的转录偶联修复（TCR）;这种类型的修复是已知的靶向大体积病变，如与紫外线暴露相关的病变。有趣的是，Mfd在氧化促进的DNA损伤修复和转录调节中的作用不同。在这里，我们使用遗传方法来测试Mfd是否保护B。结果野生型细胞存活叔丁基过氧化氢（t-BHP）暴露显着优于MFD缺陷型细胞。这种保护作用是独立的UvrA，经典的TCR/核苷酸切除修复（NER）途径的组成部分。此外，我们的研究结果表明，Mfd和MutY，一种处理8-oxoG DNA错配的DNA糖基化酶，共同保护细胞免受氧化损伤产生的损伤。我们还测试了Mfd在暴露于t-BHP的饥饿细胞中的突变中的作用。在氧化应激的条件下，Mfd和MutY可以在突变的形成中一起工作。出乎意料的是，当细胞暴露于蛋白质氧化剂二酰胺时，Mfd增加了存活率。在这种类型的氧化应激下，细胞的存活率不受MutY或UvrA.ConclusionsThese结果是显着的，因为他们表明，Mfd介导的错误倾向修复的DNA和保护细胞免受氧化的蛋白质通过影响基因表达; Mfd缺陷导致增加的基因表达的OhrR抑制剂，控制细胞对有机过氧化物暴露的反应。这些观察结果表明，Mfd在经历氧化应激的细胞中的功能超出了DNA修复因子。
BackgroundPrevious reports showed that mutagenesis in nutrient-limiting conditions is dependent on Mfd in Bacillus subtilis. Mfd initiates one type of transcription-coupled repair (TCR); this type of repair is known to target bulky lesions, like those associated with UV exposure. Interestingly, the roles of Mfd in repair of oxidative-promoted DNA damage and regulation of transcription differ. Here, we used a genetic approach to test whether Mfd protected B. subtilis from exposure to two different oxidants.ResultsWild-type cells survived tert-butyl hydroperoxide (t-BHP) exposure significantly better than Mfd-deficient cells. This protective effect was independent of UvrA, a component of the canonical TCR/nucleotide excision repair (NER) pathway. Further, our results suggest that Mfd and MutY, a DNA glycosylase that processes 8-oxoG DNA mismatches, work together to protect cells from lesions generated by oxidative damage. We also tested the role of Mfd in mutagenesis in starved cells exposed to t-BHP. In conditions of oxidative stress, Mfd and MutY may work together in the formation of mutations. Unexpectedly, Mfd increased survival when cells were exposed to the protein oxidant diamide. Under this type of oxidative stress, cells survival was not affected by MutY or UvrA.ConclusionsThese results are significant because they show that Mfd mediates error-prone repair of DNA and protects cells against oxidation of proteins by affecting gene expression; Mfd deficiency resulted in increased gene expression of the OhrR repressor which controls the cellular response to organic peroxide exposure. These observations point to Mfd functioning beyond a DNA repair factor in cells experiencing oxidative stress.