Faculty of Biology I, Department of Microbiology, Ludwig-Maximilians-University of Munich, Martinsried, Germany.
Munich Center for Integrated Protein Science (CIPSM), Munich, Germany.
EMBO J. 2019 Aug 15;38(16):e101650. doi: 10.15252/embj.2019101650. Epub 2019 Jul 17.
Small regulatory RNAs (sRNAs) are crucial components of many stress response systems. The envelope stress response (ESR) of Gram-negative bacteria is a paradigm for sRNA-mediated stress management and involves, among other factors, the alternative sigma factor E (σ ) and one or more sRNAs. In this study, we identified the MicV sRNA as a new member of the σ regulon in Vibrio cholerae. We show that MicV acts redundantly with another sRNA, VrrA, and that both sRNAs share a conserved seed-pairing domain allowing them to regulate multiple target mRNAs. V. cholerae lacking σ displayed increased sensitivity toward antimicrobials, and over-expression of either of the sRNAs suppressed this phenotype. Laboratory selection experiments using a library of synthetic sRNA regulators revealed that the seed-pairing domain of σ -dependent sRNAs is strongly enriched among sRNAs identified under membrane-damaging conditions and that repression of OmpA is crucial for sRNA-mediated stress relief. Together, our work shows that MicV and VrrA act as global regulators in the ESR of V. cholerae and provides evidence that bacterial sRNAs can be functionally annotated by their seed-pairing sequences.
小调控 RNA（sRNAs）是许多应激反应系统的重要组成部分。革兰氏阴性菌的包膜应激反应（ESR）是 sRNA 介导的应激管理的典范，涉及替代 sigma 因子 E（σ）和一个或多个 sRNAs 等因素。在这项研究中，我们鉴定了霍乱弧菌中的 MicV sRNA 是 σ 调控子的新成员。我们表明，MicV 与另一个 sRNA VrrA 冗余，并且这两个 sRNA 共享一个保守的种子配对结构域，允许它们调节多个靶 mRNA。缺乏 σ 的 V. cholerae 对抗菌药物的敏感性增加，并且这两个 sRNA 中的任何一个的过表达都抑制了这种表型。使用合成 sRNA 调节剂文库进行的实验室选择实验表明，σ 依赖性 sRNA 的种子配对结构域在膜损伤条件下鉴定的 sRNA 中强烈富集，并且 OmpA 的抑制对于 sRNA 介导的应激缓解至关重要。总之，我们的工作表明 MicV 和 VrrA 在霍乱弧菌的 ESR 中作为全局调节剂发挥作用，并提供了证据表明细菌 sRNAs 可以通过其种子配对序列进行功能注释。
