Tuning the sequence specificity of a transcription terminator.
Tuning the sequence specificity of a transcription terminator.
复制标题
调整转录终止子的序列特异性。
DOI：
10.1007/s00294-019-00939-1
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发表时间：
2019
期刊：
影响因子：
2.5
通讯作者：
Berger,JamesM
中科院分区：
文献类型：
--
作者：
Lawson,MichaelR;Berger,JamesM
细菌六聚体解旋酶Rho是一种典型的序列特异性转录终止子，它通常会阻止一组已定义的转录本的合成，特别是那些含有富含胞嘧啶的3‘-非翻译区的转录本。然而，在翻译应激条件下，在转录因子NusG的辅助下，Rho也可以终止胞嘧啶缺乏部位的转录。最近对大肠杆菌中Rho·NusG相互作用的结构、生化和计算研究有助于确定NusG是如何重新编程Rho活性的。NusG被发现是Rho的变构激活剂，直接与解旋酶的ATPase马达结构域结合，促进非理想(富含嘌呤)靶RNA周围的Rho环的关闭。NusG作用于Rho的方式有助于解释转录终止子如何被外部因素排除在RNA聚合酶上，如抗终止蛋白NUSE、NusG paralog RfaH和RNA聚合酶偶联的核糖体。总的来说，对NusG和Rho之间的联系的理解为在细菌的基因表达过程中如何保持转录和翻译的保真度提供了新的见解。
The bacterial hexameric helicase known as Rho is an archetypal sequence-specific transcription terminator that typically halts the synthesis of a defined set of transcripts, particularly those bearing cytosine-rich 3′-untranslated regions. However, under conditions of translational stress, Rho can also terminate transcription at cytosine-poor sites when assisted by the transcription factor NusG. Recent structural, biochemical, and computational studies of the Rho·NusG interaction inEscherichia colihave helped establish how NusG reprograms Rho activity. NusG is found to be an allosteric activator of Rho that directly binds to the ATPase motor domain of the helicase and facilitates closure of the Rho ring around non-ideal (purine-rich) target RNAs. The manner in which NusG acts on Rho helps to explain how the transcription terminator is excluded from acting on RNA polymerase by exogenous factors, such as the antitermination protein NusE, the NusG paralog RfaH, and RNA polymerase-coupled ribosomes. Collectively, an understanding of the link between NusG and Rho provides new insights into how transcriptional and translational fidelity are maintained during gene expression in bacteria.