Roadblock Repression of Transcription by Bacillus subtilis CodY
Roadblock Repression of Transcription by Bacillus subtilis CodY
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DOI：
10.1016/j.jmb.2011.06.012
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发表时间：
2011-08-26
影响因子：
5.6
通讯作者：
Sonenshein, Abraham L.
中科院分区：
文献类型：
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作者：
Belitsky, Boris R.;Sonenshein, Abraham L.
CodY是一种全局转录调节因子，已知其直接或间接控制枯草芽孢杆菌中100多种基因和操纵子的表达。使用突变分析和DNA酶I足迹实验相结合，我们确定了两个高亲和力的CodY结合位点，有助于抑制ybgE基因，并出现独立的行动。其中一个位于转录起始位点下游80 bp处，是ybgE阻遏的主要原因。使用体外转录实验，我们证明了在CodY的存在下，合成了终止于下游CodY结合位点的短于预期的ybgE转录物。因此，CodY与下游位点的结合通过路障机制抑制转录。观察到类似的提前终止的转录bcaP和yufN，其他两个CodY调控的基因与结合位点的启动子下游。与路障机制雅阁，如果转录修复偶联因子Mid失活，CodY介导的下游位点的抑制部分缓解。(C)2011爱思唯尔有限公司保留所有权利。
CodY is a global transcriptional regulator that is known to control, directly or indirectly, expression of more than 100 genes and operons in Bacillus subtilis. Using a combination of mutational analysis and DNase I footprinting experiments, we identified two high-affinity CodY-binding sites that contribute to repression of the ybgE gene and appear to act independently. One of these sites, located 80 bp downstream of the transcription start site, accounted for the bulk of ybgE repression. Using in vitro transcription experiments, we demonstrated that in the presence of CodY, a shorter-than-expected ybgE transcript that terminates at the downstream CodY-binding site was synthesized. Thus, CodY binding to the downstream site represses transcription by a roadblock mechanism. Similar premature termination of transcription was observed for bcaP and yufN, two other CodY-regulated genes with binding sites downstream of the promoter. In accord with the roadblock mechanism, CodY-mediated repression at downstream sites was partly relieved if the transcription repair coupling factor Mid was inactivated. (C) 2011 Elsevier Ltd. All rights reserved.