Department of Microbiology, University of Washington, Seattle, Washington, USA.
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
mBio. 2019 Oct 8;10(5):e02253-19. doi: 10.1128/mBio.02253-19.
-Acyl homoserine lactone (AHL) quorum sensing (QS) controls expression of over 200 genes in . There are two AHL regulatory systems: the LasR-LasI circuit and the RhlR-RhlI system. We mapped transcription termination sites affected by AHL QS in , and in doing so we identified AHL-regulated small RNAs (sRNAs). Of interest, we noted that one particular sRNA was located within the locus. We found that , which encodes the enzyme that produces the AHL -butanoyl-homoserine lactone (C4-HSL), is controlled by a 5' untranslated region (UTR)-derived sRNA we name RhlS. We also identified an antisense RNA encoded opposite the beginning of the open reading frame, which we name asRhlS. RhlS accumulates as wild-type cells enter stationary phase and is required for the production of normal levels of C4-HSL through activation of translation. RhlS also directly posttranscriptionally regulates at least one other unlinked gene, . The asRhlS appears to be expressed at maximal levels during logarithmic growth, and we suggest RhlS may act antagonistically to the asRhlS to regulate translation. The -encoded sRNAs represent a novel aspect of RNA-mediated tuning of QS. The opportunistic human pathogen possesses multiple quorum sensing systems that regulate and coordinate production of virulence factors and adaptation to different environments. Despite extensive research, the regulatory elements that play a role in this complex network are still not fully understood. By using several RNA sequencing techniques, we were able to identify a small regulatory RNA we named RhlS. RhlS increases translation of RhlI, a key enzyme in the quorum sensing pathway, and represses the mRNA encoding one of the siderophore pyoverdine receptors. Our results highlight a new regulatory layer of quorum sensing and contribute to the growing understanding of the role regulatory RNAs play in bacterial physiology.
酰基高丝氨酸内酯 (AHL) 群体感应 (QS) 控制着 中超过 200 个基因的表达。有两种 AHL 调节系统：LasR-LasI 回路和 RhlR-RhlI 系统。我们绘制了受 AHL QS 影响的 转录终止位点，并在此过程中鉴定了 AHL 调节的小 RNA (sRNA)。值得注意的是，我们注意到一个特定的 sRNA 位于 基因座内。我们发现， 编码产生 AHL -丁酰 -高丝氨酸内酯 (C4-HSL) 的酶，受我们命名为 RhlS 的 5'非翻译区 (UTR) 衍生 sRNA 控制。我们还鉴定了一种与 开放阅读框起始相对的反义 RNA，我们将其命名为 asRhlS。当野生型细胞进入稳定期时，RhlS 积累，并通过激活 翻译来产生正常水平的 C4-HSL。RhlS 还直接转录后调节至少另一个不相关的基因， 。asRhlS 似乎在对数生长期表达水平最高，我们认为 RhlS 可能与 asRhlS 拮抗调节 翻译。 编码的 sRNAs 代表 RNA 介导的 QS 调谐的一个新方面。机会性病原体 拥有多个群体感应系统，这些系统调节和协调毒力因子的产生以及适应不同的环境。尽管进行了广泛的研究，但在这个复杂网络中起作用的调节元件仍未完全理解。通过使用几种 RNA 测序技术，我们能够鉴定出一种我们命名为 RhlS 的小调节 RNA。RhlS 增加了群体感应途径中的关键酶 RhlI 的翻译，并抑制了编码铁载体 pyoverdine 受体之一的 mRNA。我们的结果强调了 群体感应的新调节层，并有助于越来越多地了解调节 RNA 在细菌生理学中的作用。
