Institute for Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany; Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, 75124 Uppsala, Sweden.
Institute for Molecular Infection Biology, University of Würzburg, 97080 Würzburg, Germany.
Mol Cell. 2018 Jun 7;70(5):971-982.e6. doi: 10.1016/j.molcel.2018.04.017. Epub 2018 May 24.
The conserved RNA-binding protein ProQ has emerged as the centerpiece of a previously unknown third large network of post-transcriptional control in enterobacteria. Here, we have used in vivo UV crosslinking and RNA sequencing (CLIP-seq) to map hundreds of ProQ binding sites in Salmonella enterica and Escherichia coli. Our analysis of these binding sites, many of which are conserved, suggests that ProQ recognizes its cellular targets through RNA structural motifs found in small RNAs (sRNAs) and at the 3' end of mRNAs. Using the cspE mRNA as a model for 3' end targeting, we reveal a function for ProQ in protecting mRNA against exoribonucleolytic activity. Taken together, our results underpin the notion that ProQ governs a post-transcriptional network distinct from those of the well-characterized sRNA-binding proteins, CsrA and Hfq, and suggest a previously unrecognized, sRNA-independent role of ProQ in stabilizing mRNAs.
保守的 RNA 结合蛋白 ProQ 已经成为肠杆菌中以前未知的第三个大型转录后调控网络的核心。在这里，我们使用体内 UV 交联和 RNA 测序（CLIP-seq）来绘制沙门氏菌和大肠杆菌中数百个 ProQ 结合位点。我们对这些结合位点的分析表明，ProQ 通过在小 RNA（sRNA）和 mRNA 3' 端发现的 RNA 结构基序来识别其细胞靶标。使用 cspE mRNA 作为 3' 端靶向的模型，我们揭示了 ProQ 在保护 mRNA 免受核酸外切酶活性影响方面的功能。总之，我们的结果支持这样一种观点，即 ProQ 调控着一个与 CsrA 和 Hfq 等特征明确的 sRNA 结合蛋白不同的转录后网络，并表明 ProQ 在稳定 mRNA 方面具有以前未被认识到的、不依赖 sRNA 的作用。
