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: 7196971
• 负责人: Kit J Pogliano
• 金额: $ 32.1万
• 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/7196971
• 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

DESCRIPTION (provided by applicant): 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.

描述（由申请人提供）：芽孢杆菌属和梭菌属的细菌产生异常持久和长寿的孢子，这些孢子是炭疽和肉毒杆菌中毒的感染因子，并在另一个细胞的细胞质中组装。这种独特的细胞结构（内生孢子）是由一种类似吞噬的过程产生的，称为吞噬。在吞噬过程中，较大的母细胞的膜围绕较小的前孢子迁移，直到它完全被包围在母细胞的细胞质中。吞噬为细菌细胞的动态能力提供了一个戏剧性的例子，但其机制仍不清楚。我们已经开发了新的工具，用于研究吞噬，膜融合和蛋白质定位，并确定在这些步骤中的突变缺陷。融合缺陷型突变体在吞噬和细胞分裂的最后一步都有缺陷，并且影响也参与染色体分离的最后阶段的保守蛋白质。我们认为，这些蛋白质协调染色体分离与细胞分裂的完成，以确保细胞分离不会损害不完全分离的染色体。我们还确定了两种机制，其中膜移动周围的前孢子，其中之一取决于SpollD肽聚糖水解酶。我们将采取细胞生物学，遗传学和生物化学相结合的方法来研究肽聚糖水解的空间调控，介导吞噬的蛋白质-蛋白质相互作用，以及了解细菌细胞催化膜融合和动态组织的机制。吞噬提供了一种生物学系统来研究对所有细菌都至关重要的细胞生物学事件，例如蛋白质定位和膜融合。它还需要肽聚糖水解酶，肽聚糖水解酶存在于所有合成肽聚糖的细菌中，并且具有潜在的致命性，因为它们的活性可以导致细胞裂解而无需严格的空间和时间调节。事实上，许多商业抗生素的致命性需要这些水解酶。吞噬提供了一个理想的系统，了解细菌如何控制这些潜在的致命酶，这是有吸引力的目标，为新的抗生素，并有可能确定新的药物靶点的蛋白质，重塑细菌膜或介导细菌蛋白质的定位。