The yeast Rat1 exonuclease promotes transcription termination by RNA polymerase II
The yeast Rat1 exonuclease promotes transcription termination by RNA polymerase II
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DOI：
10.1038/nature03041
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发表时间：
2004-11-25
期刊：
影响因子：
64.8
通讯作者：
Buratowski, S
中科院分区：
文献类型：
--
作者：
Kim, M;Krogan, NJ;Buratowski, S
RNA聚合酶II(RNAPII)最大亚基的羧基末端结构域(CTD)由多个七肽重复组成，其共有序列为YSPTSPS。不同的CTD磷酸化模式作为各种信使RNA处理因子结合的识别位点，从而耦合转录和mRNA处理(1)。多聚腺苷化因子通过CTD丝氨酸2(参考文献2)的磷酸化而被共转录招募。2)并且这些因子也是转录终止所必需的(3，4)。RNAPII转录通过聚(A)位点，RNA被聚腺苷酸化机制切割，切割位点下游的RNA被降解。我们发现Rtt103和Rat1/Rai1 5‘->；3’外切酶位于蛋白质编码基因的3‘端。在rat1-1或rai1Delta细胞中，RNA3‘到聚腺苷酸化位点的稳定性很高，在许多基因上都出现了终止缺陷。这些发现支持一个模型，在该模型中，Poly(A)位点被Rat1切割并随后降解3‘-下游RNA引发转录终止(5，6)。
The carboxy-terminal domain (CTD) of the RNA polymerase II (RNApII) largest subunit consists of multiple heptapeptide repeats with the consensus sequence YSPTSPS. Different CTD phosphorylation patterns act as recognition sites for the binding of various messenger RNA processing factors, thereby coupling transcription and mRNA processing(1). Polyadenylation factors are co-transcriptionally recruited by phosphorylation of CTD serine 2 (ref. 2) and these factors are also required for transcription termination(3,4). RNApII transcribes past the poly(A) site, the RNA is cleaved by the polyadenylation machinery, and the RNA downstream of the cleavage site is degraded. Here we show that Rtt103 and the Rat1/Rai1 5' --> 3' exonuclease are localized at 3' ends of protein coding genes. In rat1-1 or rai1Delta cells, RNA 3' to polyadenylation sites is greatly stabilized and termination defects are seen at many genes. These findings support a model in which poly(A) site cleavage and subsequent degradation of the 3'-downstream RNA by Rat1 trigger transcription termination(5,6).