Perrone Filomena, De Siena Barbara, Muscariello Lidia, Kendall Sharon L, Waddell Simon J, Sacco Margherita
Dipartimento di Scienze e Tecnologie Ambientali Biologiche e Farmaceutiche, Università della Campania "Luigi Vanvitelli", Caserta, Italy.
Department of Pathobiology and Population Science, Royal Veterinary College, London, United Kingdom.
Front Microbiol. 2017 Oct 23;8:2039. doi: 10.3389/fmicb.2017.02039. eCollection 2017.
has the ability to survive inside macrophages under acid-nitrosative stress. and its ortholog in , 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 is co-transcribed with the upstream genes and , encoding efflux pump components. RTq-PCR and GFP-reporter assays showed that the gene cluster, and the orthologous region in (), was up-regulated in a null mutant, suggesting that acts as a repressor, typical of this family of regulators. We further defined the regulon using genome-wide transcriptional profiling and used reporter assays to confirm that the promoter was induced under acid-nitrosative stress. A putative 36 bp regulatory motif was identified upstream of the gene clusters in both and and purified recombinant MSMEG_3765 protein was found to bind to DNA fragments containing this motif from both and upstream regulatory regions. These results suggest that the TetR repressor controls expression of an efflux pump with an, as yet, undefined role in the mycobacterial response to acid-nitrosative stress.
具有在酸性亚硝化应激下在巨噬细胞内生存的能力。其在[具体物种]中的直系同源物在暴露于酸性亚硝化应激时被诱导。这两个基因都被注释为TetR转录调节因子，这是一类调节广泛细胞活动的蛋白质，包括多药耐药性、碳分解代谢和毒力。在这里，我们证明[基因名称]与上游基因[基因名称1]和[基因名称2]共同转录，后者编码外排泵组件。RTq-PCR和GFP报告基因检测表明，[基因名称]基因簇以及[具体物种]中的直系同源区域在[缺失基因名称]缺失突变体中上调，表明[基因名称]作为一种阻遏物发挥作用，这是该调节因子家族的典型特征。我们使用全基因组转录谱进一步定义了[基因名称]调控子，并使用报告基因检测来确认[基因名称]启动子在酸性亚硝化应激下被诱导。在[具体物种1]和[具体物种2]的基因簇上游鉴定出一个推定的36 bp调控基序，并且发现纯化的重组MSMEG_3765蛋白与来自[具体物种1]和[具体物种2]上游调控区域的含有该基序的DNA片段结合。这些结果表明，TetR阻遏物[基因名称]控制一种外排泵的表达，该外排泵在分枝杆菌对酸性亚硝化应激的反应中具有尚未明确的作用。
