小柯机器人

美国麻省理工学院Gene-Wei Li课题组揭示了枯草芽孢杆菌中功能非依赖的转录翻译。相关论文于2020年8月26日在线发表在《自然》杂志上。

研究人员发现在革兰氏阳性模式细菌枯草芽孢杆菌中RNA聚合酶（RNAP）优于先驱性核糖体，并且这种“失控转录”为总体RNA监测和新生RNA翻译调控创造了替代规则。特别是，枯草芽孢杆菌中未偶联的RNAP解释了Rho依赖性转录终止作用减弱，以及使用核糖开关和RNA结合蛋白mRNA前导分子的广泛存在。更广泛地说，研究人员在整个细菌域的不同门中鉴定了“失控转录”的广泛基因组特征。

该研究结果表明，RNAP-核糖体偶联并不是细菌的普遍特征。相反，翻译-转录偶联和“失控转录”代表了原核生物中基因组特异性调控机制的两种主要基因表达模式。

据介绍，转录和翻译的紧密结合被认为是细菌基因表达的决定性特征。先驱性核糖体可以与RNAP物理结合并在动力学上协同，从而形成信号整合中心用于共转录调控，其中包括翻译衰减和RNA质量控制。但是，尚不清楚转录-翻译偶联及其功能是否是除大肠杆菌外其它细菌的基本特征。

附：英文原文

Title: Functionally uncoupled transcription–translation in Bacillus subtilis

Author: Grace E. Johnson, Jean-Benot Lalanne, Michelle L. Peters, Gene-Wei Li

Issue&Volume: 2020-08-26

Abstract: Tight coupling of transcription and translation is considered a defining feature of bacterial gene expression1,2. The pioneering ribosome can both physically associate and kinetically coordinate with RNA polymerase (RNAP)3,4,5,6,7,8,9,10,11, forming a signal-integration hub for co-transcriptional regulation that includes translation-based attenuation12,13 and RNA quality control2. However, it remains unclear whether transcription–translation coupling—together with its broad functional consequences—is indeed a fundamental characteristic of bacteria other than Escherichia coli. Here we show that RNAPs outpace pioneering ribosomes in the Gram-positive model bacterium Bacillus subtilis, and that this ‘runaway transcription’ creates alternative rules for both global RNA surveillance and translational control of nascent RNA. In particular, uncoupled RNAPs in B. subtilis explain the diminished role of Rho-dependent transcription termination, as well as the prevalence of mRNA leaders that use riboswitches and RNA-binding proteins. More broadly, we identified widespread genomic signatures of runaway transcription in distinct phyla across the bacterial domain. Our results show that coupled RNAP–ribosome movement is not a general hallmark of bacteria. Instead, translation-coupled transcription and runaway transcription constitute two principal modes of gene expression that determine genome-specific regulatory mechanisms in prokaryotes.

DOI: 10.1038/s41586-020-2638-5

Source: https://www.nature.com/articles/s41586-020-2638-5

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html