Laboratory of Transcription, Center for DNA Fingerprinting and Diagnostics, Nampally, Hyderabad-500001, India; email:
Department of Graduate Studies, Manipal University, Manipal, Karnataka-576104, India.
Annu Rev Microbiol. 2017 Sep 8;71:687-709. doi: 10.1146/annurev-micro-030117-020432. Epub 2017 Jul 21.
At the end of the multistep transcription process, the elongating RNA polymerase (RNAP) is dislodged from the DNA template either at specific DNA sequences, called the terminators, or by a nascent RNA-dependent helicase, Rho. In Escherichia coli, about half of the transcription events are terminated by the Rho protein. Rho utilizes its RNA-dependent ATPase activities to translocate along the mRNA and eventually dislodges the RNAP via an unknown mechanism. The transcription elongation factor NusG facilitates this termination process by directly interacting with Rho. In this review, we discuss current models describing the mechanism of action of this hexameric transcription terminator, its regulation by different cis and trans factors, and the effects of the termination process on physiological processes in bacterial cells, particularly E. coli and Salmonella enterica Typhimurium.
在多步转录过程结束时，延伸中的 RNA 聚合酶（RNAP）要么在特定的 DNA 序列（称为终止子）处，要么在新生的 RNA 依赖性解旋酶 Rho 的作用下，从 DNA 模板上脱落。在大肠杆菌中，大约有一半的转录事件是由 Rho 蛋白终止的。Rho 利用其 RNA 依赖性 ATP 酶活性沿 mRNA 移动，并最终通过未知的机制使 RNAP 脱落。转录延伸因子 NusG 通过与 Rho 直接相互作用来促进这个终止过程。在这篇综述中，我们讨论了描述这个六聚体转录终止子的作用机制的现有模型，它受不同顺式和反式因子的调节，以及终止过程对细菌细胞（特别是大肠杆菌和肠炎沙门氏菌 Typhimurium）生理过程的影响。
