Temporal and spatial control of Caulobacter cell cycle

描述（由申请人提供）：申请人的目标是利用简单的模式细菌C. crescentus，了解细胞如何产生不对称和协调细胞周期进程的分化。在月牙草中，分裂前的细胞是极化的，在一极有茎，在另一极有单鞭毛。每个细胞周期都包括一个不对称分裂，产生两个形态和生理上不同的子细胞。该系统提供了遗传学、生物化学、基因组学和新的细胞学工具来研究活细胞中的蛋白质动力学。双组分信号转导蛋白的复杂磷酸化是这种生物分化和细胞周期控制的核心。本项目有三个目标：第一个目标是梳理参与细胞周期控制和分化的几种双组分蛋白的相互作用和功能。为了做到这一点，研究人员将使用基因表达谱、磷酸化分析以及细胞成像技术。第二个目标是基于最近的观察，该调节网络的几个组成部分表现出空间定位的动态行为，在细胞极点以细胞周期依赖的方式在分散分布和离散积累之间交替。为了了解它们的细胞周期空间定位与调控和功能的关系，申请人将确定控制这些信号蛋白极性定位的顺式作用序列和因子。第三个目标是使用遗传方法识别新的细胞周期调节因子。最终目的是在时间和空间上解剖控制月牙草分化和细胞周期的双组分调控网络的信号转导机制。这种基本细胞周期调节网络的组成部分在医学上重要的微生物中是保守的。对原核生物的细胞组织及其控制时空过程的机制的深入了解，不仅将弥补我们对细菌生理和调控基础知识的认识空白，而且将为合理设计新型抗菌剂提供依据。

DESCRIPTION (provided by applicant): The applicant's goal is to understand how cells can generate asymmetry and coordinate differentiation with cell cycle progression using the simple model bacterium, C. crescentus. In C. crescentus, the predivisional cell is polarized with a stalk at one pole and a single flagellum at the other pole. Every cell cycle includes an asymmetric division that gives rise to two morphologically and physiologically different daughter cells. The system affords access to genetics, biochemistry, genomics and new cytology tools to look at protein dynamics in live cells. A complex phosphorelay of two-component signal transduction proteins is at the heart of differentiation and cell cycle control in this organism. This project has three objectives: The first objective is to sort out the interactions and functions of several of the two-component proteins that participate in cell cycle control and differentiation. To do this, the investigators will use gene expression profiling, phosphorylation assays as well as cell imaging technology. The second objective is based on the recent observations that several components of this regulatory network exhibit a dynamic behavior of spatial localization, alternating between dispersed distribution and discrete accumulation at the cell pole in a cell cycle-dependent manner. To understand how their cell cycle spatial localization relates to regulation and function, the applicants will determine cis-acting sequences and factors that control polar localization of these signaling proteins. The third objective is to identify new cell cycle regulators using a genetic approach. The ultimate goal is to dissect in time and space the signal transduction mechanisms of the two-component regulatory network that controls the C. crescentus differentiation and cell cycle. Components of this essential cell cycle regulatory network are conserved among medically important microorganisms. Insights gained into the cellular organization of prokaryotes and the mechanisms used by them to control temporal and spatial processes will not only close a gap in our understanding of fundamentals of bacterial physiology and regulation, but will also provide a basis for rational design of new antibacterial agents.