RNA polymerase II (Pol II) transcribes all protein-coding genes and many noncoding RNAs in eukaryotic genomes. Although Pol II is a complex, 12-subunit enzyme, it lacks the ability to initiate transcription and cannot consistently transcribe through long DNA sequences. To execute these essential functions, an array of proteins and protein complexes interact with Pol II to regulate its activity. In this review, we detail the structure and mechanism of over a dozen factors that govern Pol II initiation (e.g., TFIID, TFIIH, and Mediator), pausing, and elongation (e.g., DSIF, NELF, PAF, and P-TEFb). The structural basis for Pol II transcription regulation has advanced rapidly in the past decade, largely due to technological innovations in cryoelectron microscopy. Here, we summarize a wealth of structural and functional data that have enabled a deeper understanding of Pol II transcription mechanisms; we also highlight mechanistic questions that remain unanswered or controversial.

中文翻译：

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RNA聚合酶II转录机器的结构和机制。

RNA 聚合酶 II (Pol II) 转录真核基因组中的所有蛋白质编码基因和许多非编码 RNA。尽管 Pol II 是一种复杂的 12 个亚基酶，但它缺乏启动转录的能力，并且不能一致地转录长 DNA 序列。为了执行这些基本功能，一系列蛋白质和蛋白质复合物与 Pol II 相互作用以调节其活性。在这篇综述中，我们详细介绍了控制 Pol II 启动（例如 TFIID、TFIIH 和 Mediator）、暂停和延伸（例如 DSIF、NELF、PAF 和 P-TEFb）的十多个因素的结构和机制。Pol II 转录调控的结构基础在过去十年中迅速发展，这主要归功于冷冻电子显微镜的技术创新。在这里，我们总结了大量的结构和功能数据，使人们能够更深入地了解 Pol II 转录机制；我们还强调尚未解答或有争议的机械问题。