MOLECULAR GENETICS OF BACILLUS SUBTILIS RNA POLYMERASE

对所有细胞来说，最基本的是改变基因模式的能力。 表达响应环境和代谢信号。在 原核生物大多数信号转导和应激反应系统 最终在转录水平发挥作用， 需要适应不断变化的条件。我们的实验重点是 RNA聚合酶在控制稳定期基因表达中的作用 革兰氏阳性菌枯草芽孢杆菌。分析将有助于 了解的功能，相互作用，和调节的 模型发育系统的转录机制，包括 RNA聚合酶催化核心，决定启动子的sigma因子 识别和相互作用的辅助因素。枯草芽孢杆菌细胞 在稳定期表现出不同的反应，包括表达 对于向非生长状态的转变、启动 孢子形成过程，遗传能力的发展，以及 胞外酶和抗生素。其他sigma因子有 在协调这些稳定阶段事件中起着核心作用。因此 重要的是要了解调节sigma的分子机制 因子活性和与RNA聚合酶核心酶的相互作用。的 该提案的主要目标是研究生理作用， 调节sigma-B，一种涉及 稳定相应力响应。生物化学和遗传学相结合 该方法将解决以下问题：（l）什么固定相 基因受sigma-B控制，以及它们的表达是如何调节的; (2)控制sigma-B活性的分子机制是什么？ （3）如何使sigma-B和其他 σ因子与RNA聚合酶核心相互作用;并且，在一个 （4）哪些发育功能是通过 由稳定期转录因子直接控制的基因 sigma-F这项研究的具体方面将直接关系到 了解广泛细菌中的稳定期调节， 包括链霉菌属的抗生素生物合成， 细菌病原体产生毒力因子。的问题 基因表达的有序调节响应于环境， 代谢和形态信号在生物学中很常见， 控制sigma因子调节和相互作用的生物化学原理 与RNA聚合酶可能与蛋白质相关， 所有生物体中的RNA聚合酶。

Fundamental to all cells is the ability to alter the pattern of gene expression in response to environmental and metabolic signals. In prokaryotes most signal transduction and stress response systems ultimately act at the transcriptional level to express sets of genes needed to adapt to changing conditions. Our experimental focus is the role of RNA polymerase in controlling stationary phase gene expression in the Gram positive bacterium Bacillus subtilis. This analysis will contribute to understanding the functions, interactions, and regulation of the transcriptional machinery of a model developmental system, including the RNA polymerase catalytic core, the sigma factors that determine promoter recognition, and interacting accessory factors. Bacillus subtilis cells manifest diverse responses in stationary phase, including expression of genes important for transition to the non-growing state, initiation of the sporulation process, development of genetic competence, and production of extracellular enzymes and antibiotics. Alternative sigma factors have a central role in coordinating these stationary phase events. Thus it is important to understand the molecular mechanisms that regulate sigma factor activity and interaction with the RNA polymerase core enzyme. The primary goal of this proposal is to investigate the physiological role and regulation of sigma-B, an alternative sigma factor implicated in stationary phase stress response. A combined biochemical and genetic approach will address the following questions: (l) What stationary phase genes are controlled by sigma-B, and how is their expression regulated; (2) What are the molecular mechanisms controlling sigma-B activity in response to stationary phase signals; (3) How do sigma-B and other dispensable sigma factors interact with RNA polymerase core; and, in an extension of this process, (4) What developmental functions are mediated by genes directly controlled by the stationary phase transcription factor sigma-F? Specific aspects of this research will be directly relevant to understanding stationary phase regulation in a broad range of bacteria, including antibiotic biosynthesis by Streptomyces species and the production of virulence factors by bacterial pathogens. The problem of ordered regulation of gene expression in response to environmental, metabolic, and morphological signals is common in biology, and the biochemical principles that govern sigma factor regulation and interaction with RNA polymerase are likely relevant to proteins that associate with RNA polymerases in all organisms.