The multicopy sRNA LhrC controls expression of the oligopeptide-binding protein OppA in Listeria monocytogenes
The multicopy sRNA LhrC controls expression of the oligopeptide-binding protein OppA in Listeria monocytogenes
复制标题
DOI：
10.1080/15476286.2015.1071011
复制
发表时间：
2015-09-02
期刊：
影响因子：
4.1
通讯作者：
Kallipolitis, Birgitte Haahr
中科院分区：
文献类型：
--
作者：
Sievers, Susanne;Lund, Anja;Kallipolitis, Birgitte Haahr
单核细胞增生李斯特菌是食源性疾病李斯特菌病的病原体。在感染过程中，单核细胞增生李斯特菌会产生一系列非编码RNA，包括多拷贝小RNA LhrC。这五种几乎相同的小RNA在应对细胞壁压力时会被高度诱导，并在转录后水平靶向毒力黏附素lapB。在此，我们证明LhrC控制着其他编码具有毒力功能的细胞壁相关蛋白的基因的表达。通过转录组学和蛋白质组学，我们确定了一组在细胞壁压力下受LhrC影响的基因。有三个靶点在RNA和蛋白质水平上都被LhrC显著下调：lmo2349、tcsA和oppA。这三个基因都编码膜相关蛋白：一种氨基酸ABC转运体的假定底物结合蛋白（Lmo2349）；刺激CD4 + T细胞的抗原TcsA，以及寡肽结合蛋白OppA，其中后两者是单核细胞增生李斯特菌完全毒力所必需的。对于OppA，我们表明LhrC通过与oppA mRNA的核糖体结合位点直接碱基配对起作用，导致其翻译受阻以及mRNA水平降低。小RNA - mRNA的相互作用依赖于LhrC中三个富含CU区域中的两个，使得两个oppA mRNA能够与一个LhrC分子结合。最后，我们发现LhrC有助于在巨噬细胞样细胞中的感染。这些发现表明LhrC在应对细胞壁压力时，在控制OppA和其他与毒力相关的细胞壁蛋白水平方面起着核心作用。
Listeria monocytogenes is the causative agent of the foodborne disease listeriosis. During infection, L. monocytogenes produces an array of non-coding RNAs, including the multicopy sRNA LhrC. These five, nearly identical sRNAs are highly induced in response to cell envelope stress and target the virulence adhesin lapB at the post-transcriptional level. Here, we demonstrate that LhrC controls expression of additional genes encoding cell envelope-associated proteins with virulence function. Using transcriptomics and proteomics, we identified a set of genes affected by LhrC in response to cell envelope stress. Three targets were significantly down-regulated by LhrC at both the RNA and protein level: lmo2349, tcsA and oppA. All three genes encode membrane-associated proteins: A putative substrate binding protein of an amino acid ABC transporter (Lmo2349); the CD4+ T cell-stimulating antigen TcsA, and the oligopeptide binding protein OppA, of which the latter 2 are required for full virulence of L. monocytogenes. For OppA, we show that LhrC acts by direct base paring to the ribosome binding site of the oppA mRNA, leading to an impediment of its translation and a decreased mRNA level. The sRNA-mRNA interaction depends on 2 of 3 CU-rich regions in LhrC allowing binding of 2 oppA mRNAs to a single LhrC molecule. Finally, we found that LhrC contributes to infection in macrophage-like cells. These findings demonstrate a central role for LhrC in controlling the level of OppA and other virulence-associated cell envelope proteins in response to cell envelope stress.