Mechanisms Governing Bacillus Mother Cell Gene Expression

芽孢杆菌母细胞基因表达的调控机制

• 批准号: 6983685
• 负责人: LEE R KROOS
• 金额: $ 31.47万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-12-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6983685
• 关键词: Bacillus subtilis; DNA directed RNA polymerase; Escherichia coli; bacterial genetics; bacterial proteins; binding proteins; developmental genetics; endopeptidases; gene expression; genetic manipulation; genetic promoter element; genetic regulatory element; genetic screening; genetic transcription; laboratory rabbit; microorganism reproduction; protease inhibitor; protein structure function; proteolysis; regulatory gene; spores; transcription factor

DESCRIPTION (provided by applicant): The objective of this research is to understand how gene expression is regulated temporally and spatially in bacteria. Sporulation of Bacillus subtilis provides an attractive experimental system to elucidate novel mechanisms of signaling and gene regulation likely to be used by other bacteria, including pathogens. During sporulation, the cell is divided into mother cell and forespore compartments, each with a copy of the genome. Different sigma subunits of RNA polymerase (RNAP) become active in each compartment at different times, accounting for much of the temporal and spatial gene regulation. In addition, transcription factors activate or repress expression of many genes. This proposal focuses on mechanisms of gene regulation in the mother cell compartment, where two sigma factors and two transcription factors are organized in a hierarchical cascade with the order sigmaE, SpoIIID, sigmaK, then GerE. Activity of each sigma is governed by a unique signaling pathway that begins in the forespore and ends with proteolytic removal of an inhibitory pro-sequence in the mother cell. Components of these signaling pathways are known, but the molecular mechanisms of signaling and proteolytic processing remain to be elucidated. One aim is to understand the mechanism of pro-sigmaK processing and its regulation by BofA. This pathway involves regulated intramembrane proteolysis (RIP) of pro-sigmaK by SpoIVFB metalloprotease. RIP is involved in crucial biological processes, but is poorly understood. RIP of pro-sigmaK by SpoIVFB provides a fantastic opportunity to break new ground. Processing of pro-sigmaE does not appear to involve RIP, but its mechanism and its regulation by a signal from the forespore are unclear. To clarify this pathway, approaches used successfully to study pro-sigmaK processing will be applied. Another aim is to investigate the importance of a feedback loop by which sigmaK RNAP negatively regulates early gene expression. This will give insight into the switch from one regulon to another, a common feature in bacterial and phage gene regulation. Finally, SpoIIID's small size and essential role in sporulation make it attractive for structure/function and genetic analyses that will add knowledge about mechanisms of transcriptional activation in bacteria.

描述（由申请人提供）：本研究的目的是了解细菌中基因表达是如何在时间和空间上进行调节的。枯草芽孢杆菌的孢子形成提供了一个有吸引力的实验系统，以阐明可能被其他细菌（包括病原体）使用的信号转导和基因调控的新机制。在孢子形成过程中，细胞分为母细胞和前孢子室，每个室都有一个基因组拷贝。RNA聚合酶（RNAP）的不同sigma亚基在不同的时间在每个隔室中变得活跃，占大部分时间和空间基因调控。此外，转录因子激活或抑制许多基因的表达。该建议侧重于母细胞隔室中的基因调控机制，其中两个sigma因子和两个转录因子以sigmaE，SpoIIID，sigmaK，然后GerE的顺序组织在分级级联中。每个σ的活性由独特的信号传导途径控制，该信号传导途径开始于前孢子，并以母细胞中抑制性前序列的蛋白水解去除结束。这些信号通路的组成部分是已知的，但信号和蛋白水解加工的分子机制仍有待阐明。目的之一是了解pro-sigmaK加工的机制及其通过BofA的调节。该途径涉及SpoIVFB金属蛋白酶对pro-sigmaK的调节性膜内蛋白水解（RIP）。RIP参与了重要的生物过程，但人们对其了解甚少。SpoIVFB的pro-sigmaK RIP提供了一个开创新局面的绝佳机会。pro-sigmaE的处理似乎不涉及RIP，但其机制和由前孢子信号调节尚不清楚。为了阐明这一途径，将应用成功用于研究pro-sigmaK处理的方法。另一个目的是研究sigmaK RNAP负调控早期基因表达的反馈回路的重要性。这将使我们深入了解从一个调节子到另一个调节子的转换，这是细菌和噬菌体基因调控的一个共同特征。最后，SpoIIID的小尺寸和在孢子形成中的重要作用使其对结构/功能和遗传分析具有吸引力，这将增加有关细菌中转录激活机制的知识。