Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8501, Japan.
Nucleic Acids Res. 2022 Jan 11;50(1):1-16. doi: 10.1093/nar/gkab612.
In eukaryotes, three RNA polymerases (RNAPs) play essential roles in the synthesis of various types of RNA: namely, RNAPI for rRNA; RNAPII for mRNA and most snRNAs; and RNAPIII for tRNA and other small RNAs. All three RNAPs possess a short flexible tail derived from their common subunit RPB6. However, the function of this shared N-terminal tail (NTT) is not clear. Here we show that NTT interacts with the PH domain (PH-D) of the p62 subunit of the general transcription/repair factor TFIIH, and present the structures of RPB6 unbound and bound to PH-D by nuclear magnetic resonance (NMR). Using available cryo-EM structures, we modelled the activated elongation complex of RNAPII bound to TFIIH. We also provide evidence that the recruitment of TFIIH to transcription sites through the p62-RPB6 interaction is a common mechanism for transcription-coupled nucleotide excision repair (TC-NER) of RNAPI- and RNAPII-transcribed genes. Moreover, point mutations in the RPB6 NTT cause a significant reduction in transcription of RNAPI-, RNAPII- and RNAPIII-transcribed genes. These and other results show that the p62-RPB6 interaction plays multiple roles in transcription, TC-NER, and cell proliferation, suggesting that TFIIH is engaged in all RNAP systems.
在真核生物中，三种 RNA 聚合酶（RNAPs）在各种类型 RNA 的合成中发挥着重要作用：即，RNAPI 用于 rRNA；RNAPII 用于 mRNA 和大多数 snRNA；RNAPIII 用于 tRNA 和其他小 RNA。这三种 RNA 聚合酶都具有一个来自其共同亚基 RPB6 的短的柔性尾巴。然而，这个共享的 N 端尾巴（NTT）的功能尚不清楚。在这里，我们表明 NTT 与一般转录/修复因子 TFIIH 的 p62 亚基的 PH 结构域（PH-D）相互作用，并通过核磁共振（NMR）呈现 RPB6 与 PH-D 结合和未结合的结构。利用现有的冷冻电镜结构，我们对与 TFIIH 结合的 RNAPII 激活的延伸复合物进行了建模。我们还提供了证据表明，通过 p62-RPB6 相互作用将 TFIIH 募集到转录位点是转录偶联核苷酸切除修复（TC-NER）的 RNAPI 和 RNAPII 转录基因的共同机制。此外，RPB6 NTT 中的点突变导致 RNAPI、RNAPII 和 RNAPIII 转录基因的转录显著减少。这些和其他结果表明，p62-RPB6 相互作用在转录、TC-NER 和细胞增殖中发挥多种作用，表明 TFIIH 参与所有 RNA 聚合酶系统。
