Department of Bacteriology I, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan.
EMBO Rep. 2011 Sep 1;12(9):911-6. doi: 10.1038/embor.2011.132.
The expression of the type III secretion system-a main determinant of virulence in Shigella-is controlled by regulator cascades VirF-InvE (VirB) and CpxAR two-component system. A screen for mutants that restore virulence in the cpxA background led to the isolation of a mutant of rodZ, a cytoskeletal protein that maintains the rod-shaped morphology of bacilli. InvE is normally repressed at 30 °C because of decreased messenger RNA (mRNA) stability, but rodZ mutants markedly increase invE-mRNA stability. Importantly, the inhibition of InvE production by RodZ can be genetically separated from its role in cell-shape maintenance, indicating that these functions are distinguishable. Thus, we propose that RodZ is a new membrane-bound RNA-binding protein that provides a scaffold for post-transcriptional regulation.
III 型分泌系统的表达——志贺氏菌毒力的主要决定因素——受到调控级联 VirF-InvE（VirB）和 CpxAR 双组分系统的控制。筛选能够在 cpxA 背景下恢复毒力的突变体导致了 rodZ 突变体的分离，rodZ 是一种维持杆菌杆状形态的细胞骨架蛋白。由于信使 RNA（mRNA）稳定性降低，InvE 在 30°C 时通常受到抑制，但 rodZ 突变体显著增加了 invE-mRNA 的稳定性。重要的是，RodZ 对 InvE 产生的抑制作用可以与其在细胞形状维持中的作用在遗传上分开，表明这些功能是可区分的。因此，我们提出 RodZ 是一种新的膜结合 RNA 结合蛋白，为转录后调控提供了一个支架。
