Centre for mRNP Biogenesis and Metabolism, Department of Molecular Biology, Aarhus University, C.F. Møllers Allé 3, Building 1130, DK-8000 Aarhus, Denmark.
Mol Cell. 2010 Nov 12;40(3):410-22. doi: 10.1016/j.molcel.2010.10.012.
Transcription and mRNA maturation are interdependent events. Although stimulatory connections between these processes within the same round of transcription are well described, functional coupling between separate transcription cycles remains elusive. Comparing time-resolved transcription profiles of single-copy integrated β-globin gene variants, we demonstrate that a polyadenylation site mutation decreases transcription initiation of the same gene. Upon depletion of the 3' end processing and transcription termination factor PCF11, endogenous genes exhibit a similar phenotype. Readthrough RNA polymerase II (RNAPII) engaged on polyadenylation site-mutated transcription units sequester the transcription initiation/elongation factors TBP, TFIIB and CDK9, leading to their depletion at the promoter. Additionally, high levels of TBP and TFIIB appear inside the gene body, and Ser2-phosphorylated RNAPII accumulates at the promoter. Our data demonstrate that 3' end formation stimulates transcription initiation and suggest that coordinated recycling of factors from a gene terminator back to the promoter is essential for sustaining continued transcription.
转录和 mRNA 成熟是相互依赖的事件。虽然在同一轮转录中这些过程之间的刺激连接得到了很好的描述，但分离转录循环之间的功能偶联仍然难以捉摸。通过比较单拷贝整合β-珠蛋白基因变体的时间分辨转录谱，我们证明多聚腺苷酸化位点突变会降低同一基因的转录起始。当耗尽 3' 端加工和转录终止因子 PCF11 时，内源性基因表现出类似的表型。在多聚腺苷酸化位点突变的转录单元上结合的通读 RNA 聚合酶 II（RNAPII）隔离转录起始/延伸因子 TBP、TFIIB 和 CDK9，导致它们在启动子处耗尽。此外，TBP 和 TFIIB 的高水平似乎出现在基因体内部，并且 Ser2 磷酸化的 RNAPII 在启动子处积累。我们的数据表明 3' 端形成刺激转录起始，并表明从基因终止子到启动子的因子的协调再循环对于维持持续转录是必不可少的。
