Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
Mol Cell. 2021 May 6;81(9):1920-1934.e9. doi: 10.1016/j.molcel.2021.02.016. Epub 2021 Mar 8.
Transcription by RNA polymerase II (Pol II) is coupled to pre-mRNA splicing, but the underlying mechanisms remain poorly understood. Co-transcriptional splicing requires assembly of a functional spliceosome on nascent pre-mRNA, but whether and how this influences Pol II transcription remains unclear. Here we show that inhibition of pre-mRNA branch site recognition by the spliceosome component U2 snRNP leads to a widespread and strong decrease in new RNA synthesis from human genes. Multiomics analysis reveals that inhibition of U2 snRNP function increases the duration of Pol II pausing in the promoter-proximal region, impairs recruitment of the pause release factor P-TEFb, and reduces Pol II elongation velocity at the beginning of genes. Our results indicate that efficient release of paused Pol II into active transcription elongation requires the formation of functional spliceosomes and that eukaryotic mRNA biogenesis relies on positive feedback from the splicing machinery to the transcription machinery.
RNA 聚合酶 II（Pol II）转录与前体 mRNA 剪接相偶联，但潜在机制仍知之甚少。共转录剪接需要在新生前体 mRNA 上组装功能性剪接体，但这是否以及如何影响 Pol II 转录尚不清楚。在这里，我们表明，剪接体成分 U2 snRNP 对前体 mRNA 分支位点识别的抑制导致人类基因的新 RNA 合成广泛且强烈减少。多组学分析表明，抑制 U2 snRNP 功能会增加 Pol II 在启动子近端区域暂停的持续时间，损害暂停释放因子 P-TEFb 的募集，并降低基因起始时 Pol II 的延伸速度。我们的结果表明，有效地将暂停的 Pol II 释放到活跃的转录延伸中需要形成功能性剪接体，并且真核 mRNA 生物发生依赖于剪接机制对转录机制的正反馈。
