α变形菌门新型全局转录调控蛋白Rrf的分子机制研究

细菌RNA聚合酶需要保守的转录起始因子(σ)、延伸因子(NusA/G)，以及终止因子(Rho)来协助其完成基因转录。然而近年来，科学家们发现不同门类的细菌进化出额外的全局转录调控蛋白，其调控RNAP的全局转录活性，对细菌的生长、环境适应等功能至关重要。申请人鉴定了一个广泛存在于α变形菌门的新型全局转录调控蛋白Rrf (RNAP-recycling factor)。初期结果显示Rrf结合在RNA聚合酶的全新位点，通过独特的方式促进RNAP的转录终止效率，Rrf缺失会导致细菌生长严重延滞。Rrf是α变形菌门发现的首个全局转录调控蛋白，本项目拟系统探索Rrf与RNAP的相互作用方式，其新型转录调控机制，以及其潜在的生理功能。

Efficient transcription of bacterial RNA polymerase（RNAP）requires the assistance of conserved transcription initiation factor (σ factors), elongation factors (NusA/G), and termination factors (Rho). In recent years, a hand of global transcriptional regulators were discovered in different bacterial phyla that globally regulate gene transcription and are essential for bacterial growth, environmental adaption, and other important physiological functions. In preliminary data, the applicant has identified a novel global transcriptional regulator Rrf (RNAP-recycling factor) that widely exists in α-proteobacteria. Rrf binds to a novel site of RNAP and facilitates RNAP termination and recycling through a unique mechanism. Loss of Rrf showed severely impaired growth of bacteria species in α-proteobacteria. Rrf is the first global transcriptional regulator discovered in α-proteobacteria. This application intends to systematically explore the interaction between Rrf and RNAP, the molecular mechanism of transcription regulation by Rrf, and the physiological functions regulated by Rrf.