Platt T
Department of Biochemistry, University of Rochester Medical Center, New York 14642.
Mol Microbiol. 1994 Mar;11(6):983-90. doi: 10.1111/j.1365-2958.1994.tb00376.x.
Escherichia coli Rho factor is required for termination of transcription at certain sites by RNA polymerase. Binding to unstructured cytosine-containing RNA target sites, subsequent RNA-dependent ATP hydrolysis, and an RNA-DNA helicase activity that presumably facilitates termination, are considered essential for Rho function. Yet the RNA recognition elements have remained elusive, the parameters relating RNA binding to ATPase activation have been obscure, and the mechanistic steps that integrate Rho's characteristics with its termination function in vitro and in vivo have been largely undefined. Recent work offers new insights into these interactions with results that are both surprising and satisfying in the context of Rho's emerging structure. These include the requirements for binding and ATPase activation by a variety of RNA substrates, dynamic analyses of Rho tracking, helicase and termination activity, and the participation of a new factor (NusG) that interacts with Rho. Models for Rho function are considered in the light of these recent revelations.
大肠杆菌Rho因子是RNA聚合酶在某些位点终止转录所必需的。与含非结构化胞嘧啶的RNA靶位点结合、随后的RNA依赖性ATP水解以及一种可能促进终止的RNA-DNA解旋酶活性，被认为是Rho功能所必需的。然而，RNA识别元件仍然难以捉摸，RNA结合与ATP酶激活之间的参数一直不清楚，并且在体外和体内将Rho的特性与其终止功能整合在一起的机制步骤在很大程度上尚未明确。最近的研究为这些相互作用提供了新的见解，其结果在Rho新出现的结构背景下既令人惊讶又令人满意。这些见解包括各种RNA底物对结合和ATP酶激活的要求、Rho跟踪、解旋酶和终止活性的动态分析，以及与Rho相互作用的新因子（NusG）的参与。根据这些最新发现，对Rho功能模型进行了探讨。
