Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
Proc Natl Acad Sci U S A. 2011 Sep 13;108(37):E709-17. doi: 10.1073/pnas.1101655108. Epub 2011 Aug 29.
A major class of bacterial small, noncoding RNAs (sRNAs) acts by base-pairing with mRNAs to alter the translation from and/or stability of the transcript. Our laboratory has shown that Hfq, the chaperone that mediates the interaction of many sRNAs with their targets, is required for the virulence of the enteropathogen Yersinia pseudotuberculosis. This finding suggests that sRNAs play a critical role in the regulation of virulence in this pathogen, but these sRNAs are not known. Using a deep sequencing approach, we identified the global set of sRNAs expressed in vitro by Y. pseudotuberculosis. Sequencing of RNA libraries from bacteria grown at 26 °C and 37 °C resulted in the identification of 150 unannotated sRNAs. The majority of these sRNAs are Yersinia specific, without orthologs in either Escherichia coli or Salmonella typhimurium. Six sRNAs are Y. pseudotuberculosis specific and are absent from the genome of the closely related species Yersinia pestis. We found that the expression of many sRNAs conserved between Y. pseudotuberculosis and Y. pestis differs in both timing and dependence on Hfq, suggesting evolutionary changes in posttranscriptional regulation between these species. Deletion of multiple sRNAs in Y. pseudotuberculosis leads to attenuation of the pathogen in a mouse model of yersiniosis, as does the inactivation in Y. pestis of a conserved, Yersinia-specific sRNA in a mouse model of pneumonic plague. Finally, we determined the regulon controlled by one of these sRNAs, revealing potential virulence determinants in Y. pseudotuberculosis that are regulated in a posttranscriptional manner.
一类主要的细菌小非编码 RNA（sRNA）通过与 mRNA 碱基配对来改变翻译和/或转录的稳定性。我们的实验室已经表明，Hfq 是介导许多 sRNA 与其靶标相互作用的伴侣蛋白，是肠道病原体假结核耶尔森氏菌毒力所必需的。这一发现表明 sRNA 在该病原体的毒力调控中发挥了关键作用，但这些 sRNA 尚不清楚。我们使用深度测序方法鉴定了假结核耶尔森氏菌在体外表达的全局 sRNA 组。对在 26°C 和 37°C 下生长的细菌的 RNA 文库进行测序，鉴定出了 150 个未注释的 sRNA。这些 sRNA 中的大多数是耶尔森氏菌特有的，在大肠杆菌或鼠伤寒沙门氏菌中没有同源物。6 个 sRNA 是假结核耶尔森氏菌特有的，不存在于密切相关的鼠疫耶尔森氏菌基因组中。我们发现，假结核耶尔森氏菌和鼠疫耶尔森氏菌之间保守的许多 sRNA 的表达在时间和对 Hfq 的依赖性上都有所不同，这表明这两个物种之间的转录后调控发生了进化变化。假结核耶尔森氏菌中多个 sRNA 的缺失会导致病原体在鼠类耶尔森氏菌病模型中的衰减，而在鼠类肺炎性鼠疫模型中，鼠疫耶尔森氏菌中保守的、耶尔森氏菌特有的 sRNA 的失活也会导致这种情况。最后，我们确定了一个 sRNA 控制的调控组，揭示了假结核耶尔森氏菌中受转录后调控的潜在毒力决定因素。
