Genetic Mechanisms in Borrelia burgdorferi Pathogenesis

伯氏疏螺旋体发病机制的遗传机制

• 批准号: 7034482
• 负责人: JON T SKARE
• 金额: $ 28.42万
• 依托单位: TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7034482
• 关键词: Borrelia; active immunization; bacterial cytopathogenic effect; bacterial genetics; biological signal transduction; borreliosis; gene expression; genetic regulatory element; laboratory mouse; membrane proteins; oxidative stress; protein purification; protein sequence; virulence

DESCRIPTION (provided by applicant): Borrelia burgdorferi, the etiologic agent of Lyme disease, is the most frequent arthropod borne infection in the United States. Despite the information obtained from the genome sequence, very little is understood regarding how this bacterium responds to the distinct niches it occupies in nature (arthropods and mammals) and no regulatory systems have been molecularly defined. The investigators long-term goal is to understand how B. burgdorferi modulates gene expression in response to environmental signals and to link this knowledge to the synthesis of specific molecules that contribute to pathogenesis. The objectives of this application are to characterize an oxygen-specific regulatory network and relate its role to the expression of genes important in the life cycle of B. burgdorferi. The hypothesis is that dissolved oxygen is an important cue that B. burgdorferi uses to sense its environment and mobilize a response via the regulatory locus perR. PerR is a metallo-regulatory protein that modulates the expression of genes involved in the oxidative stress response. B. burgdorferi perR mutants are resistant to hydrogen peroxide, suggesting that PerR represses expression of redox responsive genes in B. burgdorferi. The investigators also determined that the perR mutant is de-repressed in additional genes unrelated to the stress response, suggesting that PerR constitutes a regulon. The investigators propose to characterize the PerR regulon with the following Specific Aims: (1) Identify the genes that comprise the PerR regulon. The investigators will use a genomic and proteomic based approach to determine genes regulated by PerR in response to the redox status; (2) Determine the mechanism of PerR regulation. PerR binds metals and may be redox responsive. The investigators propose to determine which co-factors modulate PerR activity; and (3) Relate proteins regulated by the redox status of cells to in vivo expression, and protective immunity. Several antigens are upregulated in perR mutants and when oxygen levels are low. PerR regulated antigens expressed during periods of oxidative stress and repressed when oxygen is limiting will be tested as protective immunogens. The investigators predict that the PerR regulon is important for both the physiology and pathogenesis of Lyme borreliosis as it modulates the expression of genes required for resistance to toxic oxygen species and factors required for adhesion, respectively.

描述（由申请人提供）：伯氏疏螺旋体是莱姆病的病原体，是美国最常见的节肢动物传播的感染。尽管从基因组序列中获得了信息，但人们对这种细菌如何对其在自然界中占据的独特生态位（节肢动物和哺乳动物）做出反应知之甚少，也没有从分子角度定义调节系统。 研究人员的长期目标是了解伯氏疏螺旋体如何响应环境信号调节基因表达，并将这些知识与有助于发病机制的特定分子的合成联系起来。本申请的目的是表征氧特异性调节网络，并将其作用与伯氏疏螺旋体生命周期中重要的基因表达联系起来。 该假设认为，溶解氧是伯氏疏螺旋体用来感知其环境并通过调节位点 perR 动员反应的重要线索。 PerR 是一种金属调节蛋白，可调节参与氧化应激反应的基因的表达。伯氏疏螺旋体 perR 突变体对过氧化氢具有抗性，表明 PerR 抑制伯氏疏螺旋体中氧化还原反应基因的表达。 研究人员还确定 perR 突变体在与应激反应无关的其他基因中被去​​抑制，这表明 PerR 构成了调节子。研究人员建议通过以下具体目标来表征 PerR 调节子：(1) 鉴定构成 PerR 调节子的基因。研究人员将使用基于基因组和蛋白质组的方法来确定 PerR 响应氧化还原状态调节的基因； (2)确定PerR调控机制。 PerR 与金属结合并且可能具有氧化还原反应性。研究人员建议确定哪些辅因子调节 PerR 活性； (3) 将受细胞氧化还原状态调节的蛋白质与体内表达和保护性免疫联系起来。 在 perR 突变体中以及当氧气水平较低时，一些抗原会上调。 PerR 调节的抗原在氧化应激期间表达并在氧气有限时受到抑制，将作为保护性免疫原进行测试。 研究人员预测，PerR 调节子对于莱姆疏螺旋体病的生理学和发病机制都很重要，因为它分别调节抵抗有毒氧所需的基因和粘附所需因子的表达。