Borrelia burgdorferi tick phase genes and Lyme disease pathogenesis

描述（由申请人提供）：莱姆病是美国最常见的节肢动物传播疾病，是由螺旋体伯氏疏螺旋体感染引起的。伯氏疏螺旋体在自然界的维持需要通过节肢动物媒介从受感染的哺乳动物宿主获得它，在该媒介中螺旋体生长和维持，并从受感染的媒介传播到哺乳动物宿主。研究表明，B. burgdorferi会根据载体和哺乳动物环境的变化调节其基因表达，而这种方式调控的蛋白表达在B. burgdorferi的生命周期和发病机制中起着重要作用。该项目的长期目标是表征对维持蜱媒介中的伯氏疏螺旋体及其在哺乳动物宿主中的传播和传播至关重要的基因和/或蛋白质。我们利用功能和比较基因组学鉴定了在这些过程中表达受调控的伯氏疏螺旋体基因，并确定了RpoS和rp1调控的成员。这些研究强调了这样一个事实，即在体内环境中分析基因表达提供了在体外条件下模拟体内环境无法获得的信息。这些全球调控研究的结果为我们关于需要进一步研究的基因/蛋白质的决定提供了依据。所选基因在蜱中表现出独特的表达模式，因此可以作为研究载体中基因调控的范例。具体目标1和2将涉及详细的表达分析和诱变研究的结合，旨在表征表达和调控：1)BBA74，一种rposs调控的蜱虫期蛋白，在螺旋体定殖载体期间具有独特的表达谱；2)编码甘油摄取和利用所需蛋白质的Glp操纵子，这一过程在蜱虫的伯氏疏螺旋体生长和维持过程中可能特别重要。在具体目标3中，我们将在蜱媒介的不同发育阶段对伯氏疏螺旋体进行全球转录组分析，并使用一种新开发的方法阐明蜱中的RpoS， Rrp1和BosR调控，该方法允许从体内来源的转录本中对伯氏疏螺旋体基因表达进行全球评估。这些研究将为蜱媒介中的伯氏疏螺旋体的自然历史提供新的见解，进而可能对人类莱姆病的预防和治疗产生影响。

DESCRIPTION (provided by applicant): Lyme disease, the most commonly reported arthropod-borne disease in the United States, is caused by infection with the spirochete, Borrelia burgdorferi. Maintenance of B. burgdorferi in nature requires its acquisition from an infected mammalian host by an arthropod vector, growth and maintenance of the spirochete in that vector, and transmission from the infected vector to a mammalian host. Studies indicate that B. burgdorferi modulates its gene expression in response to changes in the vector and mammalian environments and expresion of proteins regulated in this maner play an important role in the B. burgdorferi life cycle and pathogenesis. The long-term objective of this project is characterization of genes and/or proteins that are crucial to maintenance of B. burgdorferi in the tick vector and its transmission to, and dissemination in, the mammalian host. We have employed functional and comparative genomics to identify B. burgdorferi genes whose expression is regulated during these processes and to define members of the RpoS and Rrp1 regulons. These investigations highlighted the fact that analysis of gene expression in the in vivo environment provides information that cannot be obtained by study under in vitro conditions designed to mimic the in vivo milieu. The results from these global regulatory studies have informed our decisions regarding genes/proteins that warrant further study. The selected genes display unique expression patterns in the tick and thus can serve as paradigms for the study of gene regulation in the vector. Specific aims 1 and 2 will involve a combination of detailed expression analyses and mutagenesis studies aimed at characterization of the expression and regulation for: 1) BBA74, an RpoS-regulated tick-phase protein with a unique expression profile during spirochete colonization of the vector; 2) the Glp operon that encodes proteins required for glycerol uptake and utilization, a process likely to be particularly important during B. burgdorferi growth and maintenance in ticks. In specific aim 3 we will perform global transcriptome analysis of B. burgdorferi during different developmental stages of the tick vector and elucidate the RpoS, Rrp1 and BosR regulons in ticks using a newly developed methodology that allows global assessment of B. burgdorferi gene expression from in vivo-derived transcripts. These studies will provide new insights into the natural history of B. burgdorferi in the tick vector that, in turn, may have implications for prevention and treatment of human Lyme disease.