Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany.
EMBO J. 2012 Oct 17;31(20):4005-19. doi: 10.1038/emboj.2012.229. Epub 2012 Aug 24.
The small RNAs associated with the protein Hfq constitute one of the largest classes of post-transcriptional regulators known to date. Most previously investigated members of this class are encoded by conserved free-standing genes. Here, deep sequencing of Hfq-bound transcripts from multiple stages of growth of Salmonella typhimurium revealed a plethora of new small RNA species from within mRNA loci, including DapZ, which overlaps with the 3' region of the biosynthetic gene, dapB. Synthesis of the DapZ small RNA is independent of DapB protein synthesis, and is controlled by HilD, the master regulator of Salmonella invasion genes. DapZ carries a short G/U-rich domain similar to that of the globally acting GcvB small RNA, and uses GcvB-like seed pairing to repress translation of the major ABC transporters, DppA and OppA. This exemplifies double functional output from an mRNA locus by the production of both a protein and an Hfq-dependent trans-acting RNA. Our atlas of Hfq targets suggests that the 3' regions of mRNA genes constitute a rich reservoir that provides the Hfq network with new regulatory small RNAs.
与蛋白质 Hfq 相关的小 RNA 构成了迄今为止已知的最大一类转录后调控因子之一。该类别中大多数先前研究的成员是由保守的独立基因编码的。在这里，通过对鼠伤寒沙门氏菌多个生长阶段的 Hfq 结合转录本进行深度测序，在 mRNA 基因座内发现了大量新的小 RNA 物种，包括 DapZ，它与生物合成基因 dapB 的 3' 区域重叠。DapZ 小 RNA 的合成独立于 DapB 蛋白的合成，并且受到 HilD 的控制，HilD 是沙门氏菌入侵基因的主要调控因子。DapZ 带有一个类似于全局作用的 GcvB 小 RNA 的短 G/U 丰富结构域，并利用 GcvB 样种子配对来抑制主要 ABC 转运蛋白 DppA 和 OppA 的翻译。这体现了从一个 mRNA 基因座产生蛋白质和 Hfq 依赖性反式作用 RNA 的双重功能输出。我们的 Hfq 靶标图谱表明，mRNA 基因的 3' 区域构成了一个丰富的储库，为 Hfq 网络提供了新的调节性小 RNA。
