Bordetella virulence gene regulation in mammalian hosts

描述(申请人提供)：波尔德氏菌属的成员为研究细菌与宿主的相互作用提供了优越的实验模型系统。尽管接种了广泛的疫苗，但百日咳杆菌和副百日咳杆菌仍在继续存在，而且这种疾病在一些国家逐渐重新出现，这强调了需要详细了解波尔德泰尔菌感染的分子决定因素。BvgAS信号转导系统调节波尔德氏菌感染循环中涉及的大多数毒力决定因素。BvgAS控制一系列基因表达状态的表达，以响应环境信号强度的增量差异。虽然关于BvgAS基因座介导的基因表达模式的范围有详细的信息，但对感染周期中的基因表达模式知之甚少。我们认为，在呼吸道中毒力因子的时空协同表达，使波氏杆菌能够在宿主体内建立长期的持久性。我们的长期目标是了解在寄主定植过程中控制毒力因子表达多样性的详细分子机制。作为迈向这一目标的必要的第一步，我们建议确定BVG调节基因在感染周期中的转录图谱。我们将利用被广泛研究和很好描述的波氏杆菌感染啮齿动物模型，通过实时RT-PCR分析和GFP荧光测量，确定波氏杆菌基因在不同的呼吸道组织和感染周期的多个时间点是如何调节的。破译这一规定的复杂性将揭开新的信息，最终将导致更好地理解波氏杆菌物种的有机体在哺乳动物宿主体内生存的机制。除了加强我们对波尔德氏菌感染所涉及的分子机制的理解外，我们的结果还应该有助于开发针对各种呼吸道病原体的治疗方法，这些病原体使用类似的策略导致疾病。

DESCRIPTION (provided by applicant): Members of the Bordetella genus provide superior experimental model systems for studying bacterial-host interactions. The continued presence of B. pertussis and B. parapertussis despite widespread vaccinations and the gradual reemergence of the disease in a number of countries emphasize the need to attain a detailed understanding of the molecular determinants of Bordetella infections. The BvgAS signal transduction system regulates the majority of virulence determinants involved in the Bordetella infectious cycle. BvgAS controls the expression of a spectrum of gene expression states in response to incremental differences in the intensity of environmental signals. Although detailed information is available about the range of gene expression patterns mediated by the BvgAS locus, little is known about the pattern of gene expression during the infectious cycle. We believe that a concerted spatial and temporal expression of virulence factors in the respiratory tract, allows Bordetella to establish long-term persistence within hosts. Our long-term goal is to understand the detailed molecular mechanisms controlling the versatility in expression of virulence factors during host colonization. As a necessary first step towards this goal, we propose to determine the transcriptional profile of Bvg-regulated genes during the infectious cycle. We will determine how Bordetella genes are regulated in different respiratory tissues and during multiple time-points of the infectious cycle by using the widely studied and well-characterized rodent models of Bordetella infections and by Real Time RT PCR analyses and measurement of GFP fluorescence. Deciphering the complexities of this regulation would unravel new information that would ultimately lead to a better understanding of the mechanisms employed by organisms of the Bordetella species to survive within mammalian hosts. In addition to enhancing our understanding of the molecular mechanisms involved in Bordetella infection, our results should contribute to the development of therapy against a wide variety of respiratory-tract pathogens, which utilize similar strategies to cause disease.