Transcriptional termination by RNA polymerase I requires the small subunit Rpa12p
Transcriptional termination by RNA polymerase I requires the small subunit Rpa12p
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DOI：
10.1073/pnas.0401393101
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发表时间：
2004-04-20
影响因子：
11.1
通讯作者：
Proudfoot, NJ
中科院分区：
文献类型：
--
作者：
Prescott, EM;Osheim, YN;Proudfoot, NJ
我们确定RNA聚合酶I（Pol I）的Rpa 12 p作为终止因子。采用转录启动、电镜染色质扩散和RT-PCR技术对酿酒酵母的rRNA编码基因进行了分析。这些证实了Pol I终止发生在野生型菌株中Reb 1 p依赖性终止子附近。然而，3'末端加工酶Rnt 1 p或Pol I的Rpa 12 p亚基的缺失突变体均显示Pol I在间隔区中转录。对于Deltarpa 12，这些间隔区聚合酶缺乏新生转录物，表明它们立即降解。Rpa 12 p与Pol II的小亚基Rpb 9 p和Pol III的Rpc 11 p的同源性，两者都涉及转录终止，指向所有三类RNA聚合酶的共同终止机制。
We identify Rpa12p of RNA polymerase I (Pol I) as a termination factor. Combined analyses using transcription run-on, electron microscopy-visualized chromatin spreading and RT-PCR have been applied to the rRNA-encoding genes of Saccharomyces cerevisiae. These confirm that Pol I termination occurs close to the Reb1p-dependent terminator in wild-type strains. However, deletion mutants for the 3' end-processing enzyme Rnt1p or the Rpa12p subunit of Pol I both show Pol I transcription in the spacer. For Deltarpa12, these spacer polymerases are devoid of nascent transcripts, suggesting they are immediately degraded. The homology of Rpa12p to the small subunit Rpb9p of Pol II and Rpc11p of Pol III, both implicated in transcriptional termination, points to a common termination mechanism for all three classes of RNA polymerase.