Forespore Engulfment During B subtilis Sporulation

枯草芽孢杆菌孢子形成过程中前孢子的吞噬

• 批准号: 7671904
• 负责人: Kit J Pogliano
• 金额: $ 3.15万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7671904
• 关键词: Affect; Anthrax disease; Antibiotics; Bacillus (bacterium); Bacillus subtilis; Bacteria; Bacterial Proteins; Biochemical Genetics; Biological; Biological Process; Botulism; Cell Separation; Cell Wall; Cell division; Cells; Cellular Structures; Chimeric Proteins; Chromosome Segregation; Chromosomes; Clostridium; Complex; Cytolysis; Cytoplasm; Diffusion; Drug Delivery Systems; Endospore-Forming Bacteria; Ensure; Enzymes; Event; Genetic; Goals; Green Fluorescent Proteins; Helix (Snails); Hydrolysis; Immobilization; In Vitro; Infectious Agent; Investigation; Life; Lipid Bilayers; Localized; Mediating; Membrane; Membrane Fusion; Membrane Proteins; Methods; Modeling; Mothers; N-Acetylmuramoyl-L-alanine Amidase; Object Attachment; Pathway interactions; Peptidoglycan; Phagocytosis; Photobleaching; Process; Protein Dynamics; Proteins; Regulation; Reproduction spores; Research; Research Personnel; Site-Directed Mutagenesis; Specificity; Staging; System; Testing; ear helix; in vivo; intracellular protein transport; macromolecule; migration; mutant; novel; programs; protein localization location; protein protein interaction; tool

Bacteria from the genera Bacillus and Clostridium produce unusually durable and long lived spores that are the infectious agent of Anthrax and Botulism, and which are assembled in the cytoplasm of another cell. This unique cell within a cell structure (the endospore) is produced by a phagocytosis-like process known as engulfment. During engulfment, the membrane of the larger mother cell migrates around the smaller forespore, until it is completely enclosed within the mother cell cytoplasm. Engulfment provides a dramatic example of the dynamic capabilities of the bacterial cell, but its mechanism remains unclear. We have developed new tools for the study of engulfment, membrane fusion and protein localization and identified mutants defective in these steps. The fusion defective mutant is defective in both the final step of engulfment and cell division, and affects a conserved protein also involved in the final stages of chromosome segregation. We suggest that these proteins coordinate chromosome segregation with the completion of cell division, to ensure that cell separation does not damage an incompletely segregated chromosome. We have also identified two mechanisms by which the membranes move around the forespore, one of which depends on the SpollD peptidoglycan hydrolase. We will take a combined cell biological, genetic and biochemical approach to study the spatial regulation of peptidoglycan hydrolysis, the protein-protein interactions that mediate engulfment, as well as to understand the mechanisms by which bacterial cells catalyze membrane fusion and are dynamically organized. Engulfment provides a dispensable system to study cell biological events that are essential for all bacteria, such as protein localization and membrane fusion. It also requires peptidoglycan hydrolases, which are found in all bacteria that synthesize peptidoglycan, and which are potentially lethal because their activity can result in cell lysis without strict spatial and temporal regulation. Indeed, the lethality of many commercial antibiotics requires these hydrolytic enzymes. Engulfment provides an ideal system for understanding how bacteria control these potentially lethal enzymes, which are attractive targets for novel antibiotics, and has the potential to identify new drug targets in proteins that remodel bacterial membranes or mediate localization of bacterial proteins.

芽孢杆菌属和梭状芽孢杆菌属的细菌产生异常持久和长寿的孢子，这些孢子 炭疽和肉毒杆菌的感染剂，它们聚集在另一个细胞的细胞质中。 细胞结构(内孢子)中的这种独特的细胞是由一种类似吞噬的过程产生的，称为 被吞没了。在吞噬过程中，较大母细胞的膜在较小的母细胞周围迁移 前孔，直到它完全被包围在母细胞胞质内。吞噬提供了一种戏剧性的 例如细菌细胞的动态能力，但其机制尚不清楚。我们有 开发了研究吞噬、膜融合和蛋白质定位的新工具，并确定了 在这些步骤中有缺陷的突变体。融合缺陷突变体在吞噬的最后一步都是有缺陷的 和细胞分裂，并影响一种保守的蛋白质，该蛋白质也参与染色体的最后阶段 种族隔离。我们认为这些蛋白质协调染色体分离和细胞的完成。 分裂，以确保细胞分离不会损害不完全分离的染色体。我们有 还确定了膜在前孔周围移动的两种机制，其中一种依赖于 关于SpollD肽聚糖水解酶的研究。我们将采取细胞生物学、遗传学和生化相结合的方法 研究肽聚糖水解酶的空间调节的方法，即蛋白质-蛋白质相互作用 介导吞噬，以及了解细菌细胞催化膜的机制 融合，并动态组织。吞噬作用为研究细胞生物学提供了一个不可缺少的系统 对所有细菌都至关重要的事件，如蛋白质定位和膜融合。它还要求 肽聚糖水解酶，存在于所有合成肽聚糖的细菌中，它们是 可能是致命的，因为它们的活动可以导致细胞裂解，而不是严格的空间和时间调节。 事实上，许多商业抗生素的杀伤力需要这些水解酶。吞没提供了 一种理想的系统，用于了解细菌如何控制这些具有吸引力的潜在致命酶 新抗生素的靶点，并有可能在改造的蛋白质中识别新的药物靶点 细菌膜或介导细菌蛋白质的定位。