Mutagenesis in Chlamydia trachomatis via allelic exchange

 描述(由申请人提供)：沙眼衣原体在美国是一个重要的健康问题。由于急性和慢性病的流行及其对健康和社会经济的综合影响，存在着相当大的负担。衣原体是专性的细胞内寄生虫，经历了一个复杂的发育周期。所有衣原体都表达III型分泌系统(T3SS)，根据与其他表达T3SS的病原体的相似性，这一机制可能在整个发病机制中做出了重要贡献。尽管T3s与衣原体毒力的明确联系已被证明是困难的，但新获得的从基因上操纵衣原体的能力为进展打开了新的大门。我们提供了描述第一个衣原体特异性自杀载体的初步数据，并建议利用这一新方法来针对T3SS基因进行失活。具体地说，我们将进一步开发自杀载体系统，并直接在特定的T3S效应器基因中产生零突变。我们还提出了有条件地停用T3S能力的方法。在这些研究结束时，我们将建立使整个衣原体研究界受益的分子工具。此外，我们还将更好地了解T3SS是如何促进衣原体毒力的。

 DESCRIPTION (provided by applicant): Chlamydia trachomatis represents a significant health concern in the United States. A substantial burden exists due to the prevalence and the combined health and socioeconomic impact of acute and chronic disease. Chlamydiae are obligate intracellular parasites that undergo a complex developmental cycle. All Chlamydia species express a type III secretion system (T3SS), and based on analogy with other T3SS-expressing pathogens, this mechanism likely contributes significantly to overall pathogenesis. Although definitive association of T3S with chlamydial virulence has proven difficult, the newly-acquired ability to genetically manipulate chlamydiae has opened new doors for progress. We present preliminary data describing the first ever Chlamydia-specific suicide vector and propose to leverage this new approach to target T3SS genes for inactivation. Specifically we will further develop the suicide vector system and directly create null mutations in specific T3S effector genes. We also propose approaches to conditionally inactivate T3S capability. At the end of these studies, we will have established molecular tools that will benefit the entire Chlamydia research community. In addition, we will gain a better understanding of how the T3SS contributes to chlamydial virulence.