BORDETELLA VIRULENCE REGULATION IN VITRO AND IN VIVO

描述（改编自申请人的摘要）：几乎所有的 已知由百日咳博德特氏菌合成的毒力因子， 人百日咳的病原体，以及支气管败血性波氏杆菌， 会导致其他动物的呼吸道疾病， 由Bvg信号转导系统调节。Bvg也 负调节一类外膜蛋白的产生 在B。B的鞭毛合成和运动。 支气管炎 博德特氏菌物种交替的能力 在不同的表型阶段之间， 多年来，人们一直认为BVG的作用是... 在感染周期中介导的信号转导是未知的。 研究人员的实验将集中在以下问题上： 1)博德特氏菌毒力基因如何以及为何受Bvg调控，以及2） 调控基因产物的功能是什么？解决 他们将采用比较的方法， 人类病原体B的研究。百日咳及其密切相关的 动物病原体B。支气管炎 他们在体外建立了 研究信号转导生物化学的遗传分析 操纵毒力调节子的方法，以及天然宿主- 用于表征呼吸道感染的动物模型。这些 这是这个提议的基础。 这项研究计划首先从分子方面进行检查， 使用纯化的蛋白质的信号转导和 BvgA和BvgS在E.杆菌他们还将讨论机制 BvgS的信号识别，这些基础研究将有助于 体内分析。 Bvg信号改变的影响 然后使用动物模型评估转导途径， B。支气管败血症和B.百日咳。对确定的突变体的研究将 伴随着一种方法的发展， 确定呼吸道中博德特氏菌种群的时相 组织. B毒力调节子之间的关系。 百日咳和B.支气管败血症将被调查，与 特别强调Bvg负调控的基因座。 最后，他们将评估假定的粘附素的功能， B感染自然宿主时产生的毒素。支气管炎 一 为此目的将使用使用“异位表达”的新方法。 通过从广泛的角度考虑Bvg调节子，他们希望 发现其在发病机制中的作用。

DESCRIPTION (Adapted from applicant's abstract): Nearly all of the known virulence factors synthesized by Bordetella pertussis, the causative agent of human whooping cough, and Bordetella bronchiseptica, which causes respiratory disease in other animals, are positively regulated by the Bvg signal transduction system. Bvg also negatively regulates production of a class of outer membrane proteins in B. pertussis and flagella synthesis and motility in B. bronchiseptica. The ability of Bordetella species to alternate between distinct phenotypic phases in response to environmental conditions has been recognized for many years, yet the role of Bvg- mediated signal transduction in the infectious cycle is unknown. The investigators' experiments will focus on the following questions: 1) How and why are Bordetella virulence genes regulated by Bvg, and 2) What are the functions of the regulated gene products? To address these they will use a comparative approach by conducting parallel studies with the human pathogen B. pertussis and the closely related animal pathogen B. bronchiseptica. They have established in vitro assays for studying the biochemistry of signal transduction, genetic methods for manipulating the virulence regulon, and natural host- animal models for characterizing respiratory tract infection. These form the foundation for this proposal. The research plan begins with an examination of molecular aspects of signal transduction using purified proteins and measurements of BvgA and BvgS function in E. coli. They will also address mechanisms of signal recognition by BvgS and these basic studies will facilitate an in vivo analysis. The effect of alterations in Bvg signal transduction pathways will then be assessed using animal models for B. bronchiseptica and B. pertussis. Studies with defined mutants will be accompanied by the development of a method for directly determining the phase of Bordetella populations in respiratory tissue. The relationship between the virulence regulons of B. pertussis and B. bronchiseptica will be investigated next, with specific emphasis on loci that are negatively regulated by Bvg. Finally, they will assess the functions of putative adhesins and toxins during infection of natural hosts by B. bronchiseptica. A novel approach using "ectopic expression" will be used for this purpose. By considering the Bvg regulon from a broad perspective they hope to discover its role in pathogenesis.