The Yeast 5′-3′ Exonuclease Rat1p Functions during Transcription Elongation by RNA Polymerase II
The Yeast 5′-3′ Exonuclease Rat1p Functions during Transcription Elongation by RNA Polymerase II
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DOI：
10.1016/j.molcel.2010.01.019
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发表时间：
2010-02-26
期刊：
影响因子：
16
通讯作者：
Jensen, Torben Heick
中科院分区：
文献类型：
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作者：
Jimeno-Gonzalez, Silvia;Haaning, Line Lindegaard;Jensen, Torben Heick
RNA聚合酶II（RNAPII）转录蛋白质编码基因的终止发生在切割/聚腺苷酸化位点的下游。根据“鱼雷”模型，5 '-3'核酸外切酶Rat 1 p/Xrn 2 p攻击切割的前体mRNA的新形成的5'端，导致仍在转录的RNAPII终止。在这里，我们证明了S的类似作用。rat 1 p基因在基因体内。我们发现，RNAPII的rpb 1-N488 D突变施加的转录持续性缺陷Rat 1 p失活后得到纠正。重要的是，Rat 1 p依赖性转录终止发生在多聚腺苷酸化位点的上游。遗传和生物化学证据表明，mRNA加帽在rpb 1-N488 D细胞中是有缺陷的，这导致Rat 1 p水平沿基因位点的所有沿着增加。一致地，Rat 1 p依赖性RNAPII终止也在加帽缺陷型ceg 1 -63菌株中观察到。我们的数据表明，Rat 1 p可以终止参与无帽RNA产生的RNAPII分子，而不管它们在基因座上的位置如何。
Termination of RNA polymerase II (RNAPII) transcription of protein-coding genes occurs downstream of cleavage/polyadenylation sites. According to the "torpedo" model, the 5'-3' exonuclease Rat1p/Xrn2p attacks the newly formed 5' end of the cleaved pre-mRNA, causing the still transcribing RNAPII to terminate. Here we demonstrate a similar role of S. cerevisiae Rat1p within the gene body. We find that the transcription processivity defect imposed on RNAPII by the rpb1-N488D mutation is corrected upon Rat1p inactivation. Importantly, Rat1p-dependent transcription termination occurs upstream the polyadenylation site. Genetic and biochemical evidence demonstrate that mRNA capping is defective in rpb1-N488D cells, which leads to increased levels of Rat1p all along the gene locus. Consistently, Rat1p-dependent RNAPII termination is also observed in the capping-deficient ceg1-63 strain. Our data suggest that Rat1p serves to terminate RNAPII molecules engaged in the production of uncapped RNA, regardless of their position on the gene locus.