BORDETELLA VIRULENCE REGULATION IN VITRO AND IN VIVO

描述(改编自申请人的摘要)：几乎所有 百日咳杆菌合成的已知毒力因子 人类百日咳的病原体，以及支气管败血波氏杆菌， 在其他动物中引起呼吸道疾病，是肯定的 由BVG信号转导系统调节。BVG也 负性调节一类外膜蛋白的产生 百日咳杆菌和百日咳杆菌鞭毛的合成和运动 支气管败血症。波尔德氏菌属物种的交替能力 在不同的表型阶段之间对环境的响应 条件已经被认识到很多年了，然而BVG的作用- 感染周期中介导的信号转导尚不清楚。 调查人员的实验将集中在以下问题上： 1)BVG是如何和为什么调控波尔德氏菌毒力基因的，以及2) 受调控的基因产物有哪些功能？致信地址 他们将使用比较的方法，进行平行 人类百日咳杆菌及其亲缘关系的研究 动物病原体支气管败血杆菌。他们已经在体外建立了 信号转导、遗传、生物化学研究方法 操纵毒力调节子的方法和自然寄主- 描述呼吸道感染的动物模型。这些 形成了这项提议的基础。 研究计划开始于对分子方面的检查 利用纯化蛋白进行的信号转导及其测量 BvgA和BvgS在大肠杆菌中起作用。他们还将讨论机制问题 BvgS的信号识别和这些基础研究将有助于 活体分析。BVG信号变化的影响 转导通路随后将使用动物模型进行评估 支气管败血症和百日咳杆菌。对已定义突变体的研究将 伴随着一种方法的发展，直接 呼吸系统中波氏杆菌种群相的测定 组织。研究了白僵菌的毒力调节因子之间的关系。 接下来将调查百日咳和支气管败血杆菌， 特别强调受BVG负向调控的基因座。 最后，他们将评估推定的粘附素和 败血型支气管炎杆菌感染自然宿主的毒素。一个 使用“异位表达”的新方法将被用于这一目的。 通过从更广泛的角度考虑BVG法规，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.