Role of Hfq in Vibrio cholerae virulence

描述（由申请人提供）：霍乱弧菌引起严重的霍乱。我们发现，Hfq，RNA结合蛋白，是必不可少的霍乱弧菌的毒力。hfq的缺失消除了乳鼠肠道的霍乱弧菌定殖，但对体外生长的影响极小，并且不影响已知定殖因子的表达。因此，Hfq似乎控制以前未描述的途径霍乱的发病机制。 在大肠在大肠杆菌中，Hfq与许多小的非翻译RNA（sRNA）结合，调节它们的活性，从而控制多种基因的表达。Hfq还与E.大肠杆菌中，并直接改变基因表达。虽然霍乱弧菌中的Hfq可能通过类似的机制起作用，但霍乱弧菌和大肠杆菌中的hfq的不同表型。大肠杆菌的研究表明，这些蛋白质结合不同的RNA，控制不同的调节子。迄今为止，尚未表征由霍乱弧菌Hfq结合的RNA和霍乱弧菌sRNA。 该R21应用的目标是鉴定霍乱弧菌中由Hfq控制的途径，特别是促进霍乱弧菌毒力的Hfq调节基因，并表征控制其表达的机制。目标I中的实验-定义Hfq调节子-将产生关于霍乱弧菌中Hfq调节效应子的第一个知识。目标II中的实验-克隆与Hfq相互作用的sRNA和mRNA-将利用一种新的、无偏见的方法克隆相互作用的RNA。目的I和II中的实验将探索Hfq的哪些相互作用伴侣和下游效应物有助于霍乱弧菌毒力，从而阐明目前未知的致病介质。目标III中的实验-将sRNA与它们调节的基因相匹配并表征Hfq依赖性基因调节的过程-将为详细分析Hfq控制霍乱弧菌基因表达的机制奠定基础。这些研究还将促进Hfq介导的途径的破坏。由于Hfq有助于除霍乱弧菌之外的几种其他B类优先病原体的毒力，因此Hfq或其下游效应物可能被证明是新抗微生物剂的有价值的靶标。

DESCRIPTION (provided by applicant): Vibrio cholerae causes the severe diarrheal disease cholera. We found that Hfq, an RNA-binding protein, is essential for Vibrio cholerae virulence. Deletion of hfq abolished V. cholerae colonization of the suckling mouse intestine, but had a minimal effect on growth in vitro and did not influence expression of known colonization factors. Thus, Hfq appears to control previously undescribed pathways essential for cholera pathogenesis. In E. coli, Hfq binds to numerous small untranslated RNAs (sRNAs), modulates their activities, and thereby controls expression of a wide variety of genes. Hfq also binds to some mRNAs in E. coli and alters gene expression directly. Although Hfq in V. cholerae probably acts by similar mechanisms, the distinct phenotypes of hfq V. cholerae and E. coli suggest that the proteins bind different sets of RNAs and control distinct regulons. No RNAs bound by V. cholerae Hfq and no V. cholerae sRNAs have been characterized to date. The goals of this R21 application are to identify pathways controlled by Hfq in V. cholerae, particularly Hfq-regulated genes that contribute to V. cholerae virulence, and to characterize the mechanisms controlling their expression. Experiments in Aim I - to define the Hfq regulon - will generate the first knowledge of Hfq-regulated effectors in V. cholerae. Experiments in Aim II - cloning of sRNAs and mRNAs that interact with Hfq - will utilize a new, unbiased approach for cloning interacting RNAs. Experiments in both Aims I and II will explore which of Hfq's interaction partners and downstream effectors contribute to V. cholerae virulence and thus illuminate currently unknown mediators of pathogenesis. Experiments in Aim III - to match sRNAs to the genes they regulate and characterize processes of Hfq dependent gene regulation - will create the foundation for detailed analyses of the mechanisms by which Hfq controls gene expression in V. cholerae. These studies will also facilitate disruption of Hfq-mediated pathways. As Hfq contributes to the virulence of several other Class B Priority Pathogens in addition to V. cholerae, Hfq or its downstream effectors may prove to be valuable targets for new antimicrobial agents.