Wellcome Trust Centre for Cell Biology, The University of Edinburgh, Edinburgh EH9 3JR, UK; The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK.
Wellcome Trust Centre for Cell Biology, The University of Edinburgh, Edinburgh EH9 3JR, UK; Centre for Synthetic and Systems Biology (SynthSys), University of Edinburgh, Edinburgh EH9 3JD, UK.
Mol Cell. 2014 Jul 17;55(2):199-213. doi: 10.1016/j.molcel.2014.05.006. Epub 2014 Jun 5.
In bacteria, Hfq is a core RNA chaperone that catalyzes the interaction of mRNAs with regulatory small RNAs (sRNAs). To determine in vivo RNA sequence requirements for Hfq interactions, and to study riboregulation in a bacterial pathogen, Hfq was UV crosslinked to RNAs in enterohemorrhagic Escherichia coli (EHEC). Hfq bound repeated trinucleotide motifs of A-R-N (A-A/G-any nucleotide) often associated with the Shine-Dalgarno translation initiation sequence in mRNAs. These motifs overlapped or were adjacent to the mRNA sequences bound by sRNAs. In consequence, sRNA-mRNA duplex formation will displace Hfq, promoting recycling. Fifty-five sRNAs were identified within bacteriophage-derived regions of the EHEC genome, including some of the most abundant Hfq-interacting sRNAs. One of these (AgvB) antagonized the function of the core genome regulatory sRNA, GcvB, by mimicking its mRNA substrate sequence. This bacteriophage-encoded "anti-sRNA" provided EHEC with a growth advantage specifically in bovine rectal mucus recovered from its primary colonization site in cattle.
在细菌中，Hfq 是一种核心 RNA 伴侣，可催化 mRNA 与调节性小 RNA（sRNA）的相互作用。为了确定 Hfq 相互作用的体内 RNA 序列要求，并在细菌病原体中研究核糖调控，将 UV 交联的 Hfq 与肠出血性大肠杆菌（EHEC）中的 RNA 结合。Hfq 结合了 A-R-N（A-A/G-任何核苷酸）的重复三核苷酸基序，这些基序通常与 mRNA 中的 Shine-Dalgarno 翻译起始序列相关。这些基序与 sRNA 结合的 mRNA 序列重叠或相邻。因此，sRNA-mRNA 双链体的形成将取代 Hfq，促进其循环。在 EHEC 基因组的噬菌体衍生区域内鉴定出 55 种 sRNA，其中包括一些最丰富的与 Hfq 相互作用的 sRNA。其中一种（AgvB）通过模拟其 mRNA 底物序列来拮抗核心基因组调节 sRNA GcvB 的功能。这种噬菌体编码的“反 sRNA”为 EHEC 提供了生长优势，特别是在从其在牛中的定植部位回收的牛直肠粘液中。
