ECF sigma factors & cell envelope stress in B. subtilis

ECF 西格玛因子

• 批准号: 6876325
• 负责人: John D Helmann
• 金额: $ 46.8万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-05-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6876325
• 关键词: Bacillus subtilis; DNA directed RNA polymerase; SDS polyacrylamide gel electrophoresis; Streptomyces; antibiotics; bacterial genetics; bacterial proteins; bacteriocin; cell growth regulation; cell membrane; cell wall; chemical structure function; cytoprotection; electrospray ionization mass spectrometry; enzyme activity; enzyme mechanism; gene expression; genetic regulatory element; membrane lipids; nucleic acid sequence; physiologic stressor; polymerase chain reaction; proteomics; site directed mutagenesis; transcription factor

DESCRIPTION (provided by applicant): Our long term goal is to define the regulatory pathways that respond to cell envelope stress using Bacillus subtilis as a model system. Exposure of bacteria to antibiotics that interfere with cell wall synthesis or membrane function activates several large regulons coordinated by extracytoplasmic function (ECF) sigma factors and two-component regulatory systems (TCS). These regulons include genes involved in the inactivation or efflux of antibiotics, in remodeling of the cell surface to increase resistance, and in the production of antibiotics. We will pursue three aims directed at understanding the global stress responses elicited by cell envelope stress. First, we will characterize a bacteriocin produced by sporulating B. subtilis cells that selectively kills non-sporulating cells of the same species. This bacteriocin will be structurally characterized, its spectrum and mode of activity defined, and the role of the Sigma-W regulon in defending against bacteriocin activity will be explored. We will also characterize a Sigma-W dependent bacteriocin that is produced in response to antibiotic exposure. Second, we will investigate a TCS that responds to a variety of cell wall active antibiotics that interfere with lipid II function or cycling. This TCS, LiaRS, has an unusual sensor kinase that is representative of a family of intramembrane-sensing kinases and may interact with the LiaF membrane proten. We will explore the nature of signal-sensing by the LiaRS system and define the LiaR regulon. Third, we will use transcriptional profiling to define the stress responses elicited by exposure to antibiotics. This work will compare the stimulons associated with antibiotics with well defined mechanisms of action and closely related structural variants with altered function. In addition, the stimulons elicited by co-culture of B. subtilis with other antibiotic producing bacteria, including Bacilli and Streptomycetes, will be explored. Finally, we will identify and characterize novel antibiotic resistance mechanisms focusing on genes that are strongly induced as part of the cell envelope stress responses.

描述（由申请人提供）：我们的长期目标是定义使用枯草芽孢杆菌作为模型系统响应细胞包膜应力的调节途径。细菌暴露于干扰细胞壁合成或膜功能的抗生素中，激活了几个通过外质功能（ECF）Sigma因子和两组分量调节系统（TCS）协调的大调节。这些规范包括涉及抗生素失活或排出的基因，重塑细胞表面以增加耐药性以及抗生素的产生。我们将追求三个旨在理解细胞信封压力引起的全球压力反应的目标。首先，我们将表征通过零散的枯草芽孢杆菌细胞产生的细菌素，该细胞梭菌细胞有选择地杀死同一物种的非散孢子细胞。该细菌素将在结构上表征，其频谱和活性模式定义，并且将探讨Sigma-W调节剂在防御细菌素活性中的作用。我们还将表征Sigma-W依赖性细菌素，该细菌素是响应抗生素暴露而产生的。其次，我们将研究一个对各种细胞壁活性抗生素反应的TC，这些抗生素会干扰脂质II功能或循环。该TCS（撒谎者）具有不寻常的传感器激酶，它代表了膜内感应激酶家族，并且可能与LIAF膜蛋白相互作用。我们将探索骗子系统信号感应的性质，并定义骗子调节。第三，我们将使用转录分析来定义暴露于抗生素引起的应力反应。这项工作将将与抗生素相关的刺激与具有良好定义的作用机理和与功能变化的紧密相关的结构变体进行比较。此外，将探讨由枯草芽孢杆菌共培养与其他抗生素产生的细菌（包括杆菌和链霉菌）引起的刺激。最后，我们将识别并表征新型的抗生素抗性机制，这些抗生素抗性机制重点是强烈诱导的基因，这些基因是细胞包膜应激反应的一部分。