Department of Molecular Microbiology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, 02-096 Warsaw, Poland.
Int J Mol Sci. 2022 Apr 26;23(9):4758. doi: 10.3390/ijms23094758.
In a previous study, differential proteomic analysis was used to identify membrane proteins of the human enteropathogen , whose levels are influenced by OmpR, the transcriptional regulator in the two-component EnvZ/OmpR system. Interestingly, this analysis demonstrated that at 37 °C, OmpR negatively affects the level of over a dozen Ysc-Yop proteins, which constitute a type III secretion system (T3SS) that is essential for the pathogenicity of . Here, we focused our analysis on the role of OmpR in the expression and secretion of Yops (translocators and effectors). Western blotting with anti-Yops antiserum and specific anti-YopD, -YopE and -YopH antibodies, confirmed that the production of Yops is down-regulated by OmpR with the greatest negative effect on YopD. The RT-qPCR analysis demonstrated that, while OmpR had a negligible effect on the activity of regulatory genes and , it highly repressed the expression of . OmpR was found to bind to the promoter of the operon, suggesting a direct regulatory effect. In addition, we demonstrated that the negative regulatory influence of OmpR on the Ysc-Yop T3SS correlated with its positive role in the expression of , the master regulator of the flagellar-associated T3SS.
在之前的一项研究中，采用差异蛋白质组学分析方法鉴定了人肠道病原体的膜蛋白，其水平受双组分EnvZ/OmpR 系统转录调节剂 OmpR 的影响。有趣的是，这项分析表明，在 37°C 时，OmpR 负调控超过十几个 Ysc-Yop 蛋白的水平，这些蛋白构成了 III 型分泌系统（T3SS），对 的致病性至关重要。在这里，我们专注于 OmpR 在 Yops（转运蛋白和效应蛋白）表达和分泌中的作用。用抗 Yops 抗血清和特异性抗 YopD、-YopE 和 -YopH 抗体进行的 Western blot 分析证实，Yops 的产生受 OmpR 下调，对 YopD 的影响最大。RT-qPCR 分析表明，虽然 OmpR 对调控基因 和 的活性几乎没有影响，但它强烈抑制了 的表达。发现 OmpR 与 操纵子的启动子结合，表明存在直接的调控作用。此外，我们还证明了 OmpR 对 Ysc-Yop T3SS 的负调控作用与其在鞭毛相关 T3SS 的主要调控因子 的表达中的正作用相关。
