Characterization of the Brucella abortus virB locus

流产布鲁氏菌 virB 基因座的表征

• 批准号: 6632506
• 负责人: Renee M Tsolis
• 金额: $ 25.46万
• 依托单位: TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6632506
• 关键词: Brucella abortus; bacteria infection mechanism; bacterial genetics; bacterial proteins; cell component structure /function; confocal scanning microscopy; cow; electron microscopy; gene expression; gene mutation; genetic regulation; genetic regulatory element; immune tolerance /unresponsiveness; intracellular transport; laboratory mouse; macrophage; operon; oxidative stress; pathologic process; phagocytosis; pilus; polymerase chain reaction; protein structure function; reporter genes; vesicle /vacuole; western blottings

DESCRIPTION (provided by applicant): Brucella abortus is a facultative intracellular pathogen that is highly infectious by the aerosol route and causes chronic, debilitating disease. A key step in B. abortus infection is the establishment of persistent infection within macrophages. The bacterial genes encoding virulence mechanisms required for specific interactions between Brucella and the macrophage remain largely undiscovered. We have identified a genetic locus of B. abortus, virB, that is required for establishing infection both in macrophages and In the mouse model. The B. abortus virB locus is predicted by sequence homology to encode a type IV secretion system. Our long- range goal is to elucidate the mechanism by which the virB locus mediates intracellular survival and persistent infection. The objective of this application is to study the expression of the virB genes and compare the interaction of wild type B. abortus and virB mutants with regard to vacuolar trafficking in the macrophage. The central hypothesis of this application is that the virB locus mediates a critical interaction with the macrophage that allows B. abortus to establish infection. The rationale for the proposed research is that characterization of B. abortus virulence factors mediating specific interactions with macrophages will form the basis for new approaches to treat or prevent brucellosis. We are uniquely prepared to undertake the proposed research, because we have generated tools for studying virB expression at both the transcriptional and translational level. Furthermore, the work will be performed in an excellent research environment that is conducive to its completion. Our Department contains several funded investigators working on intracellular bacterial pathogens and excellent BL-3 facilities, as well as other shared resources available for the study of host/pathogen interactions. The central hypothesis will be tested, and the objectives of this application accomplished by pursuing the following two specific aims: (1) Identify conditions for In vitro and in vivo expression of the B. abortus virB locus and localize protein products in the bacterium, and (2) Determine the mechanism by which the virB locus enables B. abortus to survive and grow intracellularly within macrophages. We expect that the results of this work will provide the first direct evidence for expression of the B. abortus virB proteins as well as define the environmental signals that induce expression of this locus. Furthermore, our results will provide information essential to defining the cellular interaction mediated by the virB locus. These results will be significant, because they are expected to provide new targets for preventive or therapeutic interventions to be employed in the case of illegitimate use of this bacterial pathogen. In addition, it is expected that these results will advance our knowledge of type IV secretion systems, which are used by a number of different bacterial pathogens to subvert the host's defense mechanisms.

描述（由申请人提供）：流产布鲁氏菌是一种兼性布鲁氏菌 通过气溶胶途径具有高度传染性的细胞内病原体 导致慢性、使人衰弱的疾病。流产布鲁氏菌感染的关键步骤是 巨噬细胞内持续感染的建立。细菌 编码毒力机制的基因需要特定的相互作用 布鲁氏菌和巨噬细胞在很大程度上仍未被发现。我们已经确定了一个 流产布鲁氏菌 (virB) 的遗传位点，是建立感染所需的 在巨噬细胞和小鼠模型中。 B. abortus virB 基因座是 通过序列同源性预测编码IV型分泌系统。我们的长期 范围目标是阐明 virB 基因座介导的机制 细胞内存活和持续感染。此举的目的 应用是研究virB基因的表达并比较 野生型流产布鲁氏菌和 virB 突变体在液泡方面的相互作用 巨噬细胞的贩运。该应用的中心假设是 virB 基因座介导与巨噬细胞的关键相互作用 允许流产布鲁氏菌建立感染。拟议的理由 研究表明流产布鲁氏菌毒力因子介导的特征 与巨噬细胞的特定相互作用将构成新方法的基础 治疗或预防布鲁氏菌病。我们已做好独特的准备来承担 提出的研究，因为我们已经生成了研究 virB 的工具 转录和翻译水平上的表达。此外， 这项工作将在一个优秀的研究环境中进行 有利于其完成。我们的部门有几个资助的 研究细胞内细菌病原体和出色的 BL-3 的研究人员 设施以及可用于研究的其他共享资源 宿主/病原体相互作用。中心假设将被检验，并且 本申请的目标通过追求以下两个目标来实现 具体目标：（1）确定体外和体内表达的条件 B. abortus virB 基因座并定位细菌中的蛋白质产物，以及 (2) 确定virB位点使流产芽胞杆菌 在巨噬细胞内存活并在细胞内生长。我们期望 这项工作的结果将为表达 B. abortus virB 蛋白以及定义环境信号 诱导该基因座的表达。此外，我们的结果将提供 定义细胞相互作用所必需的信息 virB 基因座。这些结果将意义重大，因为它们预计将 为要采用的预防或治疗干预措施提供新的目标 如果非法使用这种细菌病原体。此外，它是 预计这些结果将增进我们对 IV 型分泌的了解 系统，许多不同的细菌病原体使用该系统来 破坏宿主的防御机制。