The RpoN-RpoS regulatory pathway in Borrelia burgdorferi

伯氏疏螺旋体中的 RpoN-RpoS 调控途径

• 批准号: 7433723
• 负责人: MICHAEL V. NORGARD
• 金额: $ 38.78万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-01 至 2009-08-13
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7433723
• 关键词: Animals; Bacteria sigma factor KatF protein; Binding; Borrelia; Borrelia burgdorferi; Complex; DNA Microarray Chip; DNA Microarray format; Disease; Genes; Genetic; Infection; Lipoproteins; Maps; Membrane; Modeling; Molecular Genetics; Nature; OmpR protein; OspC protein; Pathway interactions; Promoter Regions; Proteins; RNA polymerase sigma 54; Regulatory Pathway; Role; Sigma Factor; Ticks; Virulence; enhancer binding protein; novel; promoter; vector

DESCRIPTION (provided by applicant): Borrelia burgdorferi (Bb), the Lyme disease spirochete, undergoes dramatic adaptive changes as it cycles in nature between its diverse tick and mammalian hosts. However, little is known regarding the genetic regulatory networks that modulate Bb's infectivity and virulence. Recently, we discovered a novel regulatory pathway in Bb, wherein one alternative sigma factor (sigma N, sigmaN, sigma54, RpoN) regulates the expression of another alternative sigma factor (sigma S, sigmaS, sigma38, RpoS) which, in turn, governs the expression of key membrane lipoproteins associated with borrelial virulence. This study proposes to build on this initial observation and investigate, at the genetic and molecular levels, the novel RpoN-RpoS regulatory pathway as it pertains to Bb's infectivity and virulence. In Specific Aim 1, we will identify the activator of the RpoN-RpoS regulatory pathway; studies will focus on examining a role for the "response regulator protein 2" (Rrp2) of Bb that is predicted to be a transcriptional enhancer-binding protein. In Specific Aim 2, we will examine the mechanism by which RpoN controls the expression of RpoS, with emphasis on (i) mapping the rpoS promoter and (ii) assessing the binding of RpoN and its activator (Rrp2) to the rpoS promoter and upstream regions. Studies in Specific Aim 3 will investigate the mechanism by which the RpoN-RpoS pathway regulates the expression of a prototypic differentially regulated lipoprotein, OspC. Emphasis will be placed on analyzing key features of the ospC promoter that engender its control by RpoN via RpoS. In Specific Aim 4, we will examine the influence of the RpoN-RpoS pathway on Bb's ability to infect animals, colonize ticks, be vector-transmitted, and cause disease. Finally, in Specific Aim 5, we will use DNA microarrays to identify more globally those genes of Bb influenced by the RpoN-RpoS regulatory pathway. These combined studies will be instrumental in further characterizing the novel RpoN-RpoS regulatory pathway in Bb and for potentially identifying infection- and/or virulence-associated genes that contribute to many aspects of Bb's complex parasitic strategy.

描述（由申请人提供）：伯氏疏螺旋体（Bb）是莱姆病螺旋体，在自然界中不同的蜱虫和哺乳动物宿主之间循环时经历了巨大的适应性变化。然而，人们对调节 Bb 感染性和毒力的基因调控网络知之甚少。最近，我们在 Bb 中发现了一条新的调控途径，其中一个替代 sigma 因子（sigma N、sigmaN、sigma54、RpoN）调节另一个替代 sigma 因子（sigma S、sigmaS、sigma38、RpoS）的表达，而后者又控制与疏螺旋体毒力相关的关键膜脂蛋白的表达。本研究拟在此初步观察的基础上，在遗传和分子水平上研究与 Bb 的感染性和毒力相关的新型 RpoN-RpoS 调控途径。在具体目标1中，我们将确定RpoN-RpoS调控途径的激活剂；研究将重点检查 Bb 的“反应调节蛋白 2”(Rrp2) 的作用，预计该蛋白是一种转录增强子结合蛋白。在具体目标 2 中，我们将研究 RpoN 控制 RpoS 表达的机制，重点是 (i) 绘制 rpoS 启动子图谱，以及 (ii) 评估 RpoN 及其激活剂 (Rrp2) 与 rpoS 启动子和上游的结合地区。具体目标 3 中的研究将探讨 RpoN-RpoS 通路调节原型差异调节脂蛋白 OspC 表达的机制。重点将放在分析 ospC 启动子的关键特征，这些特征使其受 RpoN 通过 RpoS 控制。在具体目标 4 中，我们将研究 RpoN-RpoS 途径对 Bb 感染动物、定殖蜱、媒介传播和引起疾病的能力的影响。最后，在具体目标 5 中，我们将使用 DNA 微阵列来更全面地识别受 RpoN-RpoS 调控途径影响的 Bb 基因。这些综合研究将有助于进一步表征 Bb 中新的 RpoN-RpoS 调控途径，并有可能识别感染和/或毒力相关基因，这些基因有助于 Bb 复杂寄生策略的许多方面。