Analysis of the DksA regulon in the Lyme disease spirochete

摘要 严格反应是细菌用来适应营养缺乏的生理机制，并且许多 其他压力。在莱姆病的病原体伯氏疏螺旋体（Bb）中， 通过alarmone核苷酸（p）ppGpp和RNA聚合酶结合蛋白DksA。最近，我们发现 DksA在Bb毒力调控中起重要作用。首先，dksA在感染动物中高度表达 并且是Bb感染哺乳动物宿主所必需的。第二，DksA对于Bb的最佳生长至关重要。第三、 Bb需要DksA来科普代谢应激。最后，除了作为一个严格的反应功能， 作为调节因子，DksA促进有助于Bb在宿主中存活的基因的转录和/或翻译。 这些综合数据使我们假设DksA是控制Bb毒力基因的主要调节因子 表情这一假设将在两个具体目标中得到解决。在本提案的目标1中，我们将确定 DksA对Bb在蜱中的存活和持久性的贡献。在目标2中，我们将鉴定受以下因素调控的基因： 在各种体外和体内条件下的DksA。这些联合研究将（i）定义整个DksA调节子; 和（ii）提供对DksA和调节子的体内重要性的变革性理解。所得 这些发现可能会导致开发新的策略来预防和/或治疗莱姆病。

ABSTRACT Stringent response is a physiological mechanism utilized by bacteria to adapt to nutrient deprivation and many other stresses. In Borrelia burgdorferi (Bb), the etiological agent of Lyme disease, stringent response is mediated by both the alarmone nucleotides (p)ppGpp and the RNA polymerase-binding protein DksA. Recently, we found that DksA plays an essential role in regulating Bb's virulence. First, dksA is highly expressed in infected animals and is required by Bb to infect the mammalian hosts. Second, DksA is critical for Bb's optimal growth. Third, DksA is required by Bb to cope with metabolic stress. Finally, in addition to function as a stringent response regulator, DksA promotes the transcription and/or translation of genes contributing to Bb's survival in the host. These combined data give rise to our hypothesis that DksA is a master regulator governing Bb's virulence gene expression. This hypothesis will be addressed in two Specific Aims. In Aim 1 of this proposal, we will determine the contribution of DksA to Bb's survival and persistence in ticks. In Aim 2, we will identify genes regulated by DksA under various in vitro and in vivo conditions. These combined studies will (i) define the entire DksA regulon; and (ii) provide a transformative understanding of the in vivo importance of DksA and the regulon. Resultant findings could lead to the development of new strategies to prevent and/or treat Lyme disease.