Smooth to Rugose phase variation in Vibrio cholerae

霍乱弧菌引起霍乱，是水生生物的天然居民， 环境.季节性霍乱暴发发生在疾病流行并可传播的地方 国际吧霍乱弧菌引起流行病的能力与其在水生环境中的生存能力有关。 栖息地已经提出，霍乱弧菌形成生物膜的能力（即，矩阵封装， 表面相关的社区）对于其在流行病之间的水生栖息地的生存至关重要 并且有利于流行病期间的宿主间传播。的目的 建议是提高我们对生物膜基质成分，机制和 调节生物膜的形成，环二聚鸟苷酸（c- diGMP）信号传导，以及它们在霍乱弧菌生物学中的重要性。 在目标1中，我们将专注于生物膜基质组分的表征。我们将 确定弧菌多糖（VPS）结合能力和基质的定位模式 生物膜中的蛋白质，并测试我们的假设，这些蛋白质结合到VPS，以稳定 矩阵。我们将确定vps基因簇中哪些基因是生物膜所需的 阵我们还将研究一个假定的VPS裂解酶的酶学性质。最后我们 将确定已知的生物膜决定因素在霍乱弧菌发病机制中的作用。在Aim中 2、剖析生物膜形成的调控机制。生物膜调控网络由两个 正转录调节因子（VpsR和VpsT），负转录调节因子（HapR）， 以及我们最近鉴定的传感器组氨酸激酶（VpsS）。我们将确定VpsS是否 磷酸化VpsR并识别控制VpsS的重要信号。我们将描述 vps和基质蛋白基因的顺式作用特征，并阐明是否转录 调节子VpsR、VpsT和HapR直接与这些启动子相互作用。在目标3中，我们 阐明c-diGMP信号传导控制生物膜形成的分子机制。我们 将确定调节生物膜形成的c-diGMP信号蛋白是否依赖于 蛋白质相互作用为了鉴定c-di-GMP信号系统的靶蛋白， 我们将寻找与c-diGMP信号蛋白相互作用的蛋白质， 皱纹变体内的受体蛋白。然后，我们将评估这些c-diGMP信号传导 蛋白质影响霍乱弧菌的发病机制。 更好地理解生物膜形成、c-diGMP信号传导和 这两个过程在霍乱弧菌生物学中的重要性将被证明对 制定今后预测和控制霍乱流行的战略，并将 有助于鉴定用于在感染期间对抗病原体的新药物靶标。

Vibrio cholerae causes the disease cholera and is a natural inhabitant of aquatic environments. Seasonal cholera outbreaks occur where the disease is endemic and can spread worldwide. V. cholerae's ability to cause epidemics is tied to its ability to survive in aquatic habitats. It has been proposed that V. cholerae's ability to form biofilms (i.e., matrix-enclosed, surface-associated communities) is crucial for its survival in aquatic habitats between epidemics and is advantageous for host-to-host transmission during epidemics. The objective of this proposal is to improve our understanding of biofilm matrix components, the mechanisms and regulation of biofilm formation, the mechanism of cyclic dimeric guanosine monophosphate (c- diGMP) signaling, and their importance in the biology of V. cholerae. In Aim 1, we will focus on characterization of biofilm matrix components. We will determine Vibrio polysaccharide (VPS) binding capacities and localization patterns of the matrix proteins in biofilms, and test our hypothesis that these proteins bind to VPS in order to stabilize the matrix. We will determine which genes within the vps gene clusters are required for biofilm formation. We will also investigate the enzymatic properties of a putative VPS lyase. Finally, we will ascertain the contribution of known biofilm determinants in V. cholerae pathogenesis. In Aim 2, we will dissect regulation of biofilm formation. Biofilm regulatory network consists of two positive transcriptional regulators (VpsR and VpsT), a negative transcriptional regulator (HapR), and our recently-identified sensor histidine kinase (VpsS). We will determine whether VpsS phoshorylates VpsR and identify important signals that control VpsS. We will characterize the cis-acting features of the vps and matrix-protein genes and elucidate whether the transcriptional regulators VpsR, VpsT and HapR interact directly with these promoters. In Aim 3, we will elucidate the molecular mechanisms by which c-diGMP signaling controls biofilm formation. We will determine whether c-diGMP signaling proteins that modulate biofilm formation rely on protein-protein interactions. To identify the target proteins of the c-di-GMP signaling systems, we will search for proteins interacting with c-diGMP signaling proteins, as well as for c-diGMP receptor proteins within the rugose variants. We will then assess how these c-diGMP signaling proteins affect V. cholerae pathogenesis. Better understanding of the mechanism of biofilm formation, c-diGMP signaling, and the importance of both of these processes in V. cholerae biology will prove useful for the development of future strategies for predicting and controlling cholera epidemics, and will facilitate identification of novel drug targets for combating the pathogen during infection.