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）：来自芽孢杆菌和梭状芽胞杆菌的细菌会产生异常耐用的孢子，孢子是炭疽和肉毒杆菌的传染剂，并且在另一个细胞的细胞质中组装。这种独特的细胞结构（内孢子）中的这种独特的细胞是由被称为吞噬的吞噬作用过程产生的。在吞噬期间，较大的母细胞的膜围绕较小的前孔迁移，直到将其完全封闭在母细胞细胞质中为止。吞噬提供了细菌细胞动态能力的戏剧性例子，但其机制尚不清楚。我们开发了用于研究吞噬，膜融合和蛋白质定位的新工具，并确定了这些步骤中有缺陷的突变体。融合有缺陷的突变体在吞噬和细胞分裂的最后一步中都是有缺陷的，并且会影响染色体分离的最后阶段的保守蛋白。我们建议这些蛋白质将染色体分离与细胞分裂的完成，以确保细胞分离不会损害未完全隔离的染色体。我们还确定了两种机制，膜围绕前孔移动，其中一种取决于斑点肽聚糖水解酶。我们将采用一种组合细胞的生物学，遗传和生化方法来研究肽聚糖水解的空间调节，肽聚糖水解，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并动态组织的机制。吞噬提供了一个可支配的系统来研究对所有细菌所必需的细胞生物事件，例如蛋白质定位和膜融合。它还需要肽聚糖水解酶，这些水解酶在所有合成肽聚糖的细菌中都发现，并且可能致命，因为它们的活性会导致细胞裂解而无需严格的空间和时间调节。实际上，许多商业抗生素的致死性需要这些水解酶。吞噬提供了一个理想的系统，可以理解细菌如何控制这些潜在的致命酶，这些酶是新型抗生素的有吸引力的靶标，并且有潜力鉴定重塑细菌膜或介导细菌蛋白质的蛋白质中的新药物靶标。