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: 8610221
• 负责人: MICHAEL V. NORGARD
• 金额: $ 39.35万
• 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 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8610221
• 关键词: Address; Animals; Area; Arthropods; Bacteria; Bacteria sigma factor KatF protein; Binding Proteins; Borrelia; Borrelia burgdorferi; Complement; Complex; Data; Disease; Elements; Foundations; Funding; Gene Expression Regulation; Genes; Genetic; Genetic Transcription; Intervention; Investigation; Lac Repressors; Lead; Life Cycle Stages; Lipoproteins; Lyme Disease; Mammals; Membrane; Methods; Modeling; Names; Nature; OmpR protein; Operon; OspC protein; Pathogenesis; Pathway interactions; Pattern; Phase; Phenotype; Principal Investigator; Process; Progress Reports; Regulation; Regulatory Pathway; Research; Research Personnel; Role; Sigma Factor; System; Ticks; Virulence; Work; decorin; decorin binding protein B; enhancer binding protein; enzootic; mutant; novel; promoter; public health relevance; therapeutic vaccine; trait; transmission process; 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. Prior to work conducted by the principle investigator over the past funding interval, little was known regarding the genetic regulatory networks that modulate Bb's adaptive changes contributing to Bb's infectivity and virulence. To this end, we discovered a novel regulatory pathway in Bb, wherein one alternative sigma factor (CN, RpoN) regulates the expression of another alternative sigma factor (Cs, RpoS) that, in turn, governs the expression of key membrane lipoproteins associated with Bb's virulence. The pathway is controlled by an enhancer-binding protein, response regulator protein-2 (Rrp2), which first must be activated for the subsequent activation of RpoN and the consequent transcription of rpoS. Although the discovery of this regulatory network in Bb has represented an important advance in the Lyme disease field, it also has prompted many new questions regarding its direct and indirect regulatory effects, how the pathway intersects with other regulatory mechanisms, and how and to what extents various genes of Bb are influenced. Selected areas of investigation over the next funding interval will continue to address some of these salient information gaps. Accordingly, the Specific Aims of this proposal are: (1) To discern those genes directly influenced by the RpoN-RpoS pathway. We shall combine our expertise in Bb microarrays with our newly developed lac repressor/operator system to artificially control the expression of rpoS in Bb. Identified genes will become the subject of further studies (Aim 4); (2) To investigate the mechanism by which the RpoN-RpoS pathway regulates atypical expression of the decorin-binding protein (DbpB/A) operon. The dbpBA operon is under the control of the RpoN-RpoS pathway, but it has an expression pattern different from other genes controlled by RpoS (e.g., ospC). As such, dbpBA may be a model of how certain genes influenced by the pathway also are subjected to another layer of regulation. Emphasis will be placed on analyzing key features of the dbpBA promoter and upstream cis-elements; (3) To examine the expression of rpoS over the complete enzootic life cycle (tick and mammalian phases) of Bb; and (4) To examine the phenotypes of Bb mutants deficient in selected RpoS-dependent genes. These efforts will provide an expanding foundation for further characterizing the novel RpoN-RpoS regulatory network in Bb, and for potentially identifying regulatory and virulence-associated genes that contribute to many aspects of Bb's complex parasitic strategy. Understanding the roles of these genes could lead to new intervention strategies (vaccines, therapeutics) for Lyme disease.

描述（由申请人提供）：Borrelia Burgdorferi（BB），莱姆病螺旋体，随着其自然界在其多样化的tick虫和哺乳动物宿主之间的自然循环，经历了戏剧性的适应性变化。在主要研究者在过去的融资间隔内进行工作之前，关于调节BB的适应性变化的遗传调节网络几乎不知道，这导致了BB的感染性和毒力。为此，我们在BB中发现了一种新型的调节途径，其中一种替代Sigma因子（CN，RPON）调节了另一种替代Sigma因子（CS，RPOS）的表达，从而控制了与BB毒力相关的关键膜脂蛋白的表达。该途径由增强子结合蛋白，反应调节蛋白2（RRP2）控制，该途径必须首先激活RPON的随后激活和随后的RPOS转录。尽管在BB中发现了该调节网络在莱姆病领域的重要进步，但它也引发了许多有关其直接和间接调节效应的新问题，该途径如何与其他调节机制相交，以及如何以及如何以及如何以及范围的各种基因受到影响。在下一个资金间隔中进行的选定调查领域将继续解决其中一些显着信息差距。因此，该提案的具体目的是：（1）辨别那些直接受RPON-RPOS途径影响的基因。我们将在BB微阵列中将我们的专业知识与新开发的LAC阻遏物/操作员系统相结合，以人为地控制BB中RPO的表达。确定的基因将成为进一步研究的主题（AIM 4）； （2）研究RPON-RPOS途径调节装饰蛋白结合蛋白（DBPB/A）操纵子的非典型表达的机制。 DBPBA操纵子在RPON-RPOS途径的控制之下，但其表达模式与由RPOS控制的其他基因（例如OSPC）不同。因此，DBPBA可能是某些受途径影响的基因如何受到另一层调节的模型。将重点放在分析DBPBA启动子和上游顺式元素的关键特征上； （3）在BB的完整生命周期（tick和哺乳动物阶段）中检查RPO的表达； （4）检查在选定的RPOS依赖性基因中缺乏BB突变体的表型。这些努力将为进一步表征BB中新型RPON RPOS调节网络的基础提供扩展的基础，并可能识别有助于BB复杂寄生策略的许多方面的调节性和毒力相关基因。了解这些基因的作用可能会导致莱姆病的新干预策略（疫苗，疗法）。