SpoVG and PlzA Regulation of Lyme Disease Spirochete Infection Processes

五、摘要 细菌感染需要病原体在感染期间准确地产生适当水平的必需因子。 感染过程的每个阶段。了解细菌如何控制其蛋白质水平以响应 来自其宿主的线索提供了关于微生物感染特性的重要见解。这些知识也可以 揭示了改进预防和治疗疗法的新目标。 莱姆病螺旋体，伯氏疏螺旋体，通过感染脊椎动物的循环在自然界中生存 和蜱虫疾病控制和预防中心计算，大约有30万新的人类莱姆病病例， 美国每年B。伯氏螺旋体可以持续感染免疫活性的人类和其他哺乳动物， 年未能及时和充分地治疗莱姆病可能导致持续的衰弱效应， 有时，死亡。长期感染可能需要长时间的抗生素治疗。为了更好 治疗莱姆病时，对B有更深入的了解是至关重要的。burgdorferi生物学，包括 螺旋体控制毒力因子产生的机制。 我们发现疏螺旋体蛋白SpoVG以特异性和高亲和力与DNA和RNA结合。 spoVG的缺失显著损害了B。伯氏菌在蜱虫上定植并通过蜱虫传播的能力 哺乳动物。spoVG转录的失调引起细菌生理学的显著变化。我们 进一步发现SpoVG直接与另一个B相互作用。莱姆病螺旋体蛋白PlzA 环状二GMP结合蛋白。我们的研究表明，PlzA也是一个位点特异性的核酸结合蛋白， 蛋白质，和ΔplzA突变体是有缺陷的，在其感染性。在我们确定的许多受监管目标中， SpoVG和PlzA是抗原可变的VlsE表面蛋白，其对于持久性B是必需的。 伯氏感染 计划的研究将同时研究SpoVG和PlzA，以及c-di-GMP对 它们的功能。这些初步数据来自P.I.和共 调查人员对这一提议。我们的共同努力将通过以下途径对这些机制产生全面的看法： 其中B。burgdorferi控制这些关键调节因子的产生，并深入了解SpoVG如何， PlzA和c-di-GMP调节VlsE和其他毒力相关蛋白。 此外，许多其他病原菌产生SpoVG的同源物，我们对B的观察。 BurgdorferiSpoVG与该蛋白质在其他细菌病原体中的已知作用具有相似性。迄今为止， 关于SpoVG如何影响任何细菌物种的毒力和生理学是已知的。我们的互动 SpoVG和PlzA之间的发现提高了其他细菌也控制SpoVG功能的可能性 通过c-di-GMP结合蛋白计划中的调查结果将提供关于以下方面的有用见解： 许多重要的人类病原体的调节机制和感染特性。

v ABSTRACT Bacterial infections require that the pathogen accurately produce essential factors at appropriate levels during each stage of infection processes. Understanding how bacteria control levels of their proteins in response to cues from their hosts provides important insights on microbial infectious properties. Such knowledge can also reveal new targets for improved preventative and curative therapies. The Lyme disease spirochete, Borrelia burgdorferi, survives in nature through cycles of infecting vertebrates and ticks. The CDC calculates that there are approximately 300,000 new cases of human Lyme disease in the USA each year. B. burgdorferi can persistently infect immunocompetent humans and other mammals for many years. Failure to treat Lyme disease promptly and adequately can result in persistent debilitating effects or, sometimes, death. Long-term infections may require extensive periods of antibiotic treatment. In order to better treat Lyme disease, it is critical to develop a more thorough understanding of B. burgdorferi biology, including the mechanisms by which the spirochete controls production of virulence factors. We discovered that a borrelial protein, SpoVG, binds with specificity and high affinity to DNA and RNA. Deletion of spoVG significantly impaired B. burgdorferi's ability to colonize ticks and be transmitted from ticks to mammals. Dysregulation of spoVG transcription caused significant changes in bacterial physiology. We further found that SpoVG directly interacts with another B. burgdorferi protein, PlzA, the Lyme spirochete's cyclic-di-GMP-binding protein. Our studies revealed that PlzA is also a site-specific nucleic acid-binding protein, and ΔplzA mutants are defective in their infectivity. Among the many regulated targets we identified for SpoVG and PlzA is the antigenically-variable VlsE surface protein, which is essential for persistent B. burgdorferi infection. The planned studies will simultaneously investigate SpoVG and PlzA, as well as the effects of c-di-GMP on their functions. These preliminary data stemmed from long-standing collaborations between the P.I. and co- investigators of this proposal. Our combined efforts will yield a comprehensive view of the mechanisms through which B. burgdorferi controls production of these critical regulatory factors, and deep insights on how SpoVG, PlzA, and c-di-GMP regulate VlsE and other virulence-associated proteins. In addition, many other pathogenic bacteria produce homologs of SpoVG, and our observations on B. burgdorferi SpoVG bear similarities with the protein's known effects in other bacterial pathogens. To date, little is known about how SpoVG affects virulence and physiology in any bacterial species. The interactions we discovered between SpoVG and PlzA raise the possibilities that other bacteria also control SpoVG function through c-di-GMP-binding proteins. Results of the planned investigations will provide useful insights on the regulatory mechanisms and infectious properties of numerous important human pathogens.