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

项目摘要/摘要 拟议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，以增强我们对细菌基本细胞过程的理解。恰如其分 细胞分裂和染色体分离之间的空间和时间协调必须确保 染色体正确地分配给子代细胞。在大肠杆菌和许多其他细菌物种中，第一 染色体可靠分割的一步是通过细胞分裂蛋白的正确定位实现的： 除法师。已知在大肠杆菌中有三个分子系统调节FtsZ细丝的早期组装 除子(Z-环)。其中包括Min系统和类核遮挡因子SLMA，它们都 通过负调控确定Z环的定位。我们最近发现，大肠杆菌也含有 一个积极的监管系统，称为TER联系。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形环的定位外，Z环的运动 细胞分裂后期的染色体也负责它们的适当分裂。在大肠杆菌DNA泵中 FtsK是这场运动的主要来源，但它可能不是唯一的来源。尽管关键因素包括 已经确定了这些配位系统，并绘制了许多蛋白质-蛋白质相互作用的图，有 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， 对于Z环是如何以及何时形成的，人们只有一个非常大致的理解。此外，人们对如何 染色体DNA在细胞分裂过程中移动和分裂。这两个过程对细胞生存都是必不可少的。 这项提议将通过将分子生物学和遗传工具与新的最先进的技术相结合来填补这些空白 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模拟 为这些进程制定一个概念性框架。具体地说，我们将确定FtsZ原丝如何 在细胞内形成并组装成一个粘合的Z环(目标1)。我们还将调查这些步骤是如何 Z环和复制终点区之间的耦合在空间和时间上的影响 染色体通过Ter连锁蛋白(目标2)。除了研究细菌类核如何影响细胞 分裂我们还将确定细胞分裂如何作用于类核细胞并在细胞过程中移动染色体DNA 师(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提供了一个框架 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.