Borrelia burgdorferi tick phase genes and Lyme disease pathogenesis

描述(申请人提供)：莱姆病是美国最常见的节肢动物传播疾病，由伯氏疏螺旋体感染引起。在自然界中，伯氏杆菌的维持需要通过节肢动物媒介从受感染的哺乳动物宿主那里获得它，在该载体中生长和维持螺旋体，以及从受感染的媒介传播到哺乳动物宿主。研究表明，伯氏杆菌能调节其基因表达以适应载体和哺乳动物环境的变化，以这种方式调节的蛋白质的表达在伯氏杆菌的生活史和致病机制中起着重要作用。该项目的长期目标是确定对伯氏杆菌在扁虱载体中的持续存在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。我们利用功能基因组学和比较基因组学来鉴定在这些过程中表达受调控的伯氏杆菌基因，并确定rpos和Rrp1调节子的成员。这些研究强调了这样一个事实，即对体内环境中的基因表达的分析提供了在旨在模拟体内环境的体外条件下无法获得的信息。这些全球监管研究的结果为我们提供了有关基因/蛋白质的决策，值得进一步研究。所选择的基因在扁虱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。特定的目标1和2将涉及详细的表达分析和突变研究，目的是鉴定BBA74的表达和调控：1)BBA74，一种受rpos调控的滴虫相蛋白，在载体的螺旋体定植期间具有独特的表达谱；2)GLP操纵子，编码甘油吸收和利用所需的蛋白质，这一过程在伯氏狸殖吸虫的生长和维持过程中可能特别重要。在具体目标3中，我们将对不同发育阶段的白背飞虱进行全局转录组分析，并使用一种新开发的方法来阐明硬蜱中的rpos、Rrp1和BosR调节子，该方法允许从体内来源的转录本对伯氏杆菌基因的表达进行全局评估。这些研究将为了解勃氏伯氏杆菌在扁虱媒介中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.