Coordination mechanisms between cell division and chromosome segregation in E. coli

项目总结/摘要 这项工作的目的是研究细胞分裂和细胞分裂之间的关键协调机制。 染色体分离，以提高我们对细菌基本细胞过程的理解。适当 细胞分裂和染色体分离之间的空间和时间协调必须保证， 染色体正确地分配到子细胞。在大肠杆菌和许多其他细菌中， 染色体可靠分配的步骤是通过细胞分裂蛋白的正确定位来实现的： 分裂E.已知大肠杆菌调节FtsZ细丝的组装，使其在早期表达。 Z环（Z-ring）这些包括Min系统和类核闭塞因子SlmA，它们都 通过负调节确定Z环的定位。我们最近发现E.大肠杆菌还含有 一个积极的调节系统，称为Ter连接。Z环相关蛋白ZapA、ZapB和DNA 结合蛋白MatP参与了这一机制。除了Z形环的定位之外， 细胞分裂后期的染色体也负责它们的适当分配。在大肠大肠杆菌DNA泵 FtsK是这一运动的主要来源，但可能不是唯一的来源。虽然关键因素包括 这些配位系统已经被确定，许多蛋白质-蛋白质相互作用也被绘制出来， 对这些相互作用如何共同导致动态细胞水平行为的理解有限。特别是， 只有非常近似的理解如何以及何时形成Z环。也有有限的知识如何 染色体DNA在细胞分裂过程中移动和分配。这两个过程对细胞存活都是至关重要的。 这项建议将填补这些空白，结合分子生物学和遗传工具与新的国家的最先进的 显微镜和图像分析技术。除了实验研究外，我们还将使用计算机建模 为这些进程制定一个概念框架。具体来说，我们将确定FtsZ原丝是如何 在细胞中形成并组装成内聚的Z环（目标1）。我们还将研究这些步骤是如何 在空间和时间上受到Z环和复制末端区域之间的偶联的影响， 染色体通过Ter连锁蛋白（Aim 2）。除了研究细菌类核如何影响细胞外， 我们还将确定细胞分裂如何作用于类核和细胞分裂过程中染色体DNA的移动。 （目标3）。从这个项目中获得的知识将增强我们对基本细胞的理解。 并为设计有效的抗菌疗法以对抗多药耐药提供了框架 耐药细菌

PROJECT SUMMARY/ABSTRACT The aim of the proposed work is to investigate key coordination mechanisms between cell division and chromosome segregation to enhance our understanding of fundamental cellular processes in bacteria. Proper spatial and temporal coordination between cell division and chromosome segregation must guarantee that chromosomes partition correctly to daughter cells. In Escherichia coli and many other bacterial species the first step in reliable partitioning of chromosomes is achieved via proper positioning of cell division proteins: the divisome. Three molecular systems in E. coli are known to regulate the assembly of FtsZ filaments to an early divisome (the Z-ring). These include the Min system and the nucleoid occlusion factor SlmA, which both determine the localization of the Z-ring via negative regulation. We recently discovered that E. coli also harbors a positive regulatory system, referred to as the Ter linkage. Z-ring associated proteins ZapA, ZapB and DNA binding protein MatP are involved in this mechanism. In addition to positioning of the Z-ring, the movement of chromosomes in late stages of cell division is also responsible for their proper partitioning. In E. coli DNA pump FtsK is the main source of this movement but it might not be the only one. Although the key factors comprising these coordination systems have been identified and many protein-protein interactions mapped out, there is limited understanding of how these interactions collectively lead to dynamic cellular level behaviors. In particular, there is only a very approximate understanding how and when Z-ring forms. There is also limited knowledge how chromosomal DNA moves and is partitioned during cell division. Both processes are essential for cell survival. This proposal will fill these gaps by combining molecular biology and genetic tools with novel state-of-the art microscopy and image analysis techniques. In addition to experimental studies we will use computer modelling to develop a conceptual framework for these processes. Specifically, we will determine how FtsZ protofilaments form and assemble to a cohesive Z-ring in the cell (Aim 1). We will also investigate how these steps are influenced spatially and temporally by coupling between Z-ring and replication terminus region of the chromosome via the Ter linkage proteins (Aim 2). In addition to studying how bacterial nucleoids affect cell division we will also determine how cell division acts on nucleoids and moves chromosomal DNA during cell division (Aim 3). The knowledge gained from this project will enhance our understanding of fundamental cellular processes in bacteria and provide a framework for designing effective antibacterial therapies to combat multidrug resistant bacteria.