Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, Japan.
Mol Microbiol. 2011 Jan;79(2):419-32. doi: 10.1111/j.1365-2958.2010.07454.x. Epub 2010 Nov 18.
An RNA chaperon Hfq along with Hfq-binding sRNAs stably binds to RNase E in Escherichia coli. The role of the Hfq-RNase E interaction is to recruit RNase E to target mRNAs of sRNAs resulting in the rapid degradation of the mRNA-sRNA hybrid. The C-terminal scaffold region of RNase E is responsible for the interaction with Hfq. Here, we demonstrate that the scaffold region can be deleted up to residue 750 without losing the ability to cause the rapid degradation of target mRNAs mediated by Hfq/sRNAs. The truncated RNase E750 can still bind to Hfq although the truncation significantly reduces the Hfq-binding ability. We conclude that the subregion between 711 and 750 is sufficient for the functional interaction with Hfq to support the rapid degradation of ptsG mRNA although additional subregions within the scaffold are also involved in Hfq binding. Deletion of the 702-750 region greatly impairs the ability of RNase E to cause the degradation of ptsG mRNA. In addition, a polypeptide corresponding to the scaffold region binds to Hfq without the help of RNA. Finally, we demonstrate that overexpression of RhlB partially inhibits the Hfq binding to RNase E and the rapid degradation of ptsG mRNA.
在大肠杆菌中，一种 RNA 伴侣蛋白 Hfq 与 Hfq 结合的 sRNA 稳定地结合到核糖核酸酶 E 上。Hfq-RNase E 相互作用的作用是将 RNase E 招募到 sRNA 的靶 mRNA 上，导致 mRNA-sRNA 杂交体的快速降解。RNase E 的 C 端支架区域负责与 Hfq 相互作用。在这里，我们证明支架区域可以被截断到 750 位而不失去由 Hfq/sRNA 介导的靶 mRNA 快速降解的能力。尽管截断显著降低了 Hfq 结合能力，但截断的 RNase E750 仍然可以与 Hfq 结合。我们得出结论，在支架内的其他区域也参与 Hfq 结合的情况下，711 到 750 之间的亚区足以与 Hfq 进行功能相互作用，以支持 ptsG mRNA 的快速降解。删除 702-750 区域会极大地损害 RNase E 引起 ptsG mRNA 降解的能力。此外，支架区域对应的多肽在没有 RNA 帮助的情况下与 Hfq 结合。最后，我们证明 Rh1B 的过表达部分抑制了 Hfq 与 RNase E 的结合以及 ptsG mRNA 的快速降解。
