Regulation of polar development in Caulobacter

描述(由申请人提供)：细菌细胞的内部组织对许多复杂的过程至关重要。例如，细菌能够在恶劣的条件下生存，或者通过产孢子和分泌毒力因子感染宿主细胞。产孢子和许多情况下毒力因子的分泌需要蛋白质的亚细胞定位。荧光标记的使用表明，蛋白质可以在细胞内具有动态定位模式，但亚细胞定位在调节蛋白质活性方面的作用尚不清楚。组氨酸激酶是一类主要的细菌调节蛋白，在响应内部和外部信号的信号通路中发挥作用。这项研究以新月藻作为细胞分化调控的模型系统，试图确定组氨酸激酶及其假定的定位因子如何帮助调节不对称分裂所产生的一个后代的发育。这项研究的目的是：1)确定调节发育的组氨酸激酶和已知的发育调节因子之间的关系，后者是蛋白质在细胞内极地定位的主要靶标。这将通过上位性分析确定它们是否处于相同的调控途径，这两种蛋白质是否相互作用并对彼此的极性定位是必需的，以及它们基因中的单突变或双突变如何影响全球基因表达。2)确定这两种蛋白在运动调节中的作用。这将通过确定组氨酸激酶活性的作用和定位因子对该活性的影响，以及通过鉴定和研究同一调节途径中的基因来实现。总之，这些实验将有助于理解亚细胞定位如何调节调节蛋白的活性。 与公共卫生相关：过去20年的研究揭示了细菌细胞中一种意想不到的内部组织水平，这对形成抵抗宿主细胞感染的孢子等复杂过程至关重要。了解复杂的细胞过程是如何受到细胞组织和调节蛋白在特定亚细胞位置的定位的影响，将增强我们控制有益细菌和有害细菌的能力。

DESCRIPTION (provided by applicant): The internal organization of bacterial cells is critical for many complex processes. For example, bacteria are able to survive harsh conditions or infect host cells through sporulation and secretion of virulence factors. Sporulation and in many cases virulence factor secretion require subcellular localization of proteins. The use of fluorescent tags has shown that proteins can have dynamic localization patterns within the cell, but the role of subcellular localization in the modulation of regulatory protein activity is still unclear. Histidine kinases are a major class of bacterial regulatory proteins that act in the signaling pathways responding to both internal and external signals. Using Caulobacter crescentus as a model system for the regulation of cell differentiation, this study seeks to determine how a histidine kinase and its putative localization factor help regulate the development of one of the offspring resulting from asymmetric division. The aims of this study are to: 1) Determine the relationship between a histidine kinase that modulates development and a known developmental regulator that is a major target for the polar localization of proteins within the cell. This will be accomplished by determining if they are in the same regulatory pathway through epistasis analysis, if these two proteins interact and are required for each other's polar localization, and how global gene expression is affected by single or double mutants in their genes. 2) Determine the role of the two proteins in the regulation of motility. This will be accomplished by determining the role of the kinase activity of the histidine kinase and the impact of the localization factor on this activity and by the identification and study of genes in the same regulatory pathway. Together these experiments will help understand how subcellular localization can modulate the activity of regulatory proteins. PUBLIC HEALTH RELEVANCE: Studies in the last two decades have revealed an unsuspected level of internal organization in bacterial cells that is critical for such complex processes as the formation of resistant spores to the infection of host cells. Understanding how complex cellular processes are impacted by cellular organization and the localization of regulatory proteins to specific subcellular sites will enhance our ability to control both beneficil and harmful bacteria.