SpoVG and PlzA Regulation of Lyme Disease Spirochete Infection Processes

V摘要 细菌感染需要病原体在适当的水平上准确地产生必要的因子 感染过程的每个阶段。了解细菌如何控制其蛋白质水平以应对 来自宿主的线索提供了关于微生物感染特性的重要见解。这样的知识还可以 揭示改进预防和治疗方法的新目标。 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存活。 还有扁虱。美国疾病控制与预防中心估计，美国约有30万例新的人类莱姆病病例。 美国每年都有。伯氏杆菌可以持续感染免疫能力较强的人类和其他哺乳动物 好几年了。未能及时和充分地治疗莱姆病可能会导致持续的虚弱效应，或者， 有时，死亡。长期感染可能需要长时间的抗生素治疗。为了更好地 治疗莱姆病，关键是要对伯氏杆菌的生物学有更透彻的了解，包括 螺旋体控制毒力因子产生的机制。 我们发现，一种脆性蛋白SpoVG与DNA和RNA具有特异性和高亲和力。 SpoVG基因的缺失显著削弱了伯氏杆菌在硬蜱中的定殖性和从硬蜱传播的能力 对哺乳动物来说。SpoVG转录失调导致细菌生理发生显著变化。我们 进一步发现SpoVG直接与伯氏杆菌的另一种蛋白Plza相互作用，即莱姆螺旋体的 环-二-GMP结合蛋白。我们的研究表明，Plza也是一种位点特异性核酸结合蛋白 蛋白质和ΔPlzA突变体的感染性存在缺陷。在我们确定的许多受监管的目标中 SpoVG和Plza是抗原性可变的VlsE表面蛋白，对持续性B组是必不可少的。 伯氏杆菌感染。 计划中的研究将同时研究SpoVG和Plza，以及c-di-GMP对 它们的功能。这些初步数据源于P.I.和co-co之间的长期合作- 这项提议的调查人员。我们的共同努力将通过以下方式全面了解这些机制 哪些B.burgdorferi控制着这些关键监管因子的产生，以及关于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. Burgdorferi SpoVG与该蛋白在其他细菌病原体中的已知作用相似。到目前为止，几乎没有 已知SpoVG如何影响任何细菌物种的毒力和生理。我们的互动 在SpoVG和Plza之间的发现增加了其他细菌也控制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为 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.