A Novel TetR-Like Transcriptional Regulator Is Induced in Acid-Nitrosative Stress and Controls Expression of an Efflux Pump in Mycobacteria.
A Novel TetR-Like Transcriptional Regulator Is Induced in Acid-Nitrosative Stress and Controls Expression of an Efflux Pump in Mycobacteria.
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DOI：
10.3389/fmicb.2017.02039
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发表时间：
2017
影响因子：
5.2
通讯作者：
Sacco M
中科院分区：
文献类型：
--
作者：
Perrone F;De Siena B;Muscariello L;Kendall SL;Waddell SJ;Sacco M
结核分枝杆菌具有在酸性亚硝化应激下在巨噬细胞内存活的能力。M. tuberculosis Rv 1685 c及其在M.在暴露于酸-亚硝化应激时，诱导了smeglycin，MSMEG_3765。这两个基因都被注释为TetR转录调节因子，这是一个调节广泛细胞活动的蛋白质家族，包括多药耐药性、碳催化剂和毒力。在这里，我们证明了MSMEG_3765与上游基因MSMEG_3762和MSMEG_3763共转录，编码外排泵组件。RTq-PCR和GFP报告基因分析表明，MSMEG_3762/63/65基因簇和M.结核分枝杆菌（Rv 1687 c/86 c/85 c）在MSMEG_3765无效突变体中上调，表明MSMEG_3765作为阻遏物，是该调节物家族的典型。我们使用全基因组转录谱进一步定义了MSMEG_3765调节子，并使用报告基因测定证实了MSMEG_3762/63/65启动子在酸亚硝化胁迫下被诱导。在两株M.耻垢分枝杆菌和M.发现纯化的重组MSMEG_3765蛋白与来自两种结核分枝杆菌的含有该基序的DNA片段结合。耻垢分枝杆菌和M.结核病上游调控区。这些结果表明TetR阻遏物MSMEG_3765/Rv 1685 c控制外排泵的表达，在分枝杆菌对酸亚硝化应激的反应中具有尚未确定的作用。
Mycobacterium tuberculosis has the ability to survive inside macrophages under acid-nitrosative stress. M. tuberculosis Rv1685c and its ortholog in M. smegmatis, MSMEG_3765, are induced on exposure to acid-nitrosative stress. Both genes are annotated as TetR transcriptional regulators, a family of proteins that regulate a wide range of cellular activities, including multidrug resistance, carbon catabolism and virulence. Here, we demonstrate that MSMEG_3765 is co-transcribed with the upstream genes MSMEG_3762 and MSMEG_3763, encoding efflux pump components. RTq-PCR and GFP-reporter assays showed that the MSMEG_3762/63/65 gene cluster, and the orthologous region in M. tuberculosis (Rv1687c/86c/85c), was up-regulated in a MSMEG_3765 null mutant, suggesting that MSMEG_3765 acts as a repressor, typical of this family of regulators. We further defined the MSMEG_3765 regulon using genome-wide transcriptional profiling and used reporter assays to confirm that the MSMEG_3762/63/65 promoter was induced under acid-nitrosative stress. A putative 36 bp regulatory motif was identified upstream of the gene clusters in both M. smegmatis and M. tuberculosis and purified recombinant MSMEG_3765 protein was found to bind to DNA fragments containing this motif from both M. smegmatis and M. tuberculosis upstream regulatory regions. These results suggest that the TetR repressor MSMEG_3765/Rv1685c controls expression of an efflux pump with an, as yet, undefined role in the mycobacterial response to acid-nitrosative stress.