GrgA: Key Regulator of Chlamydial Physiology and potential Antichlamydial Target

 描述(由申请人提供)：这项新的R21拨款的目标是确定a)一种名为GrgA的新型衣原体特异性转录因子如何通过调节基因表达来控制衣原体生长，以及b)GrgA是否是已被公认为新型抗衣原体药物的亚甲基酰肼的靶标。衣原体是一种专性胞内细菌，具有独特的发育周期。它是最常见的性传播细菌病原体。性传播衣原体感染通常会导致不孕、流产、 宫外孕和盆腔炎。转录不仅控制衣原体的生长和致病性，而且是治疗衣原体感染的有效靶点。我们已经鉴定出一种高度新颖的转录因子，我们称之为GrgA。GrgA仅由衣原体编码，通过与因子的非保守区相互作用，激活需要初级或内务因子(聚合酶的一个亚单位)的启动子的体外转录。进一步的证据支持这一假设，即GrgA在调节衣原体生长中起关键作用，并可能成为具有治疗和预防潜力的抗衣原体药物的靶点。我们提出了两个具体的目标来检验这一假设。在目标1中，我们将确定GrgA的调节基因，并确定GrgA活性的变化如何影响衣原体的转录组表达和生长发育特性。在目标2中，我们将确定GrgA在亚苄基酰肼抑制衣原体生长中的作用。亚苄酰肼是一组对宿主细胞具有不可检测的毒性的新型抗衣原体药物，以及主导健康、育龄妇女阴道微生物群的有益乳杆菌。我们期待这项研究的三个重要结果：a)这项研究将对衣原体的转录调控产生深刻的见解；b)我们可能确认GrgA是亚苄酰肼的靶标；以及c)随着药物靶向机制的阐明，亚苄基酰肼可能被证明是研究衣原体生物学的有价值的化学探针。

 DESCRIPTION (provided by applicant): The goals of this new R21 grant are to determine a) how a novel Chlamydia-specific transcription factor designated GrgA controls chlamydial growth by regulating gene expression, and b) whether GrgA is a target for benzylidene acylhydrazides, which have been recognized as novel antichlamydials. Chlamydia is an obligate intracellular bacterium with a unique developmental cycle. It is the most common sexually transmitted bacterial pathogen. Sexually transmitted chlamydial infection often leads to infertility, abortion, ectopic pregnancy and pelvic inflammatory disease. Transcription not only controls chlamydial growth and pathogenicity, but also represents an effective therapeutic target for chlamydial infections. We have identified a highly novel transcription factor that we call GrgA. Encoded by chlamydiae only, GrgA activates transcription in vitro from promoters that require the primary or housekeeping  factor (a subunit of the RNAP polymerase) designated 66 by interacting with the non-conserved region of the  factor. Further evidence support the hypothesis that GrgA plays a critical role in the regulation of chlamydial growth, and is potentially a target for antichlamydials with therapeutic and prophylactic potentials. We propose two Specific Aims to test this hypothesis. In Aim 1, we will identify the regulon of GrgA, and determine how alterations in the GrgA activity affect the transcriptome expression, and growth and developmental properties in Chlamydia. In Aim 2, we will determine the role of GrgA in chlamydial growth inhibition by benzylidene acylhydrazides, a new group of antichlamydials with undetectable toxicity to host cells and beneficial lactobacilli that dominate the vaginal microbiome of healthy, reproductive-age women. We anticipate three significant outcomes from this study: a) this research will yield insights into transcription regulation in chlamydia; b) we may confirm that GrgA is a target of benzylidene acylhydrazides; and c) with an elucidation of the drug targeting mechanism, benzylidene acylhydrazides could prove valuable as chemical probes for studying chlamydial biology.