A regulator from Chlamydia trachomatis modulates the activity of RNA polymerase through direct interaction with the β subunit and the primary σ subunit
A regulator from Chlamydia trachomatis modulates the activity of RNA polymerase through direct interaction with the β subunit and the primary σ subunit
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DOI：
10.1101/gad.1784009
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发表时间：
2009-08-01
影响因子：
10.5
通讯作者：
Shen, Li
中科院分区：
文献类型：
--
作者：
Rao, Xiancai;Deighan, Padraig;Shen, Li
专性细胞内人类病原体沙眼衣原体经历了复杂的发育程序，涉及两种形式之间的转变：感染性基本体（EB）和快速分裂的网状体（RB）。然而，控制这一发展的监管机构尚未确定。为了揭示沙眼衣原体转录的潜在调节因子，我们筛选了沙眼衣原体基因组文库，寻找编码与 RNA 聚合酶 (RNAP) 相互作用的蛋白质的序列。我们报告了一种这样的蛋白质 CT663 的鉴定，它与 RNAP 的 β 和 Sigma 亚基相互作用。具体来说，我们发现 CT663 与 β 亚基的瓣结构域（β-flap）和初级 sigma 亚基的保守区 4（沙眼衣原体中的 sigma(66)）相互作用。我们发现 CT663 在体外抑制 sigma(66) 依赖性（但不是 sigma(28) 依赖性）转录，并且我们提供证据表明 CT663 作为 RNAP 全酶的组成部分发挥这种作用。对沙眼衣原体感染细胞的分析表明，CT663 在 RB 向 EB 转变开始时开始积累。我们的研究结果表明，CT663 作为 sigma(66) 依赖性转录的负调节因子发挥作用，促进基因表达的全局变化。这里使用的策略通常适用于遗传工具不可用的情况。
The obligate intracellular human pathogen Chlamydia trachomatis undergoes a complex developmental program involving transition between two forms: the infectious elementary body (EB), and the rapidly dividing reticulate body (RB). However, the regulators controlling this development have not been identified. To uncover potential regulators of transcription in C. trachomatis, we screened a C. trachomatis genomic library for sequences encoding proteins that interact with RNA polymerase (RNAP). We report the identification of one such protein, CT663, which interacts with the beta and sigma subunits of RNAP. Specifically, we show that CT663 interacts with the flap domain of the beta subunit (beta-flap) and conserved region 4 of the primary sigma subunit (sigma(66) in C. trachomatis). We find that CT663 inhibits sigma(66)-dependent (but not sigma(28)-dependent) transcription in vitro, and we present evidence that CT663 exerts this effect as a component of the RNAP holoenzyme. The analysis of C. trachomatis-infected cells reveals that CT663 begins to accumulate at the commencement of the RB-to-EB transition. Our findings suggest that CT663 functions as a negative regulator of sigma(66)-dependent transcription, facilitating a global change in gene expression. The strategy used here is generally applicable in cases where genetic tools are unavailable.