Ctr9, Rtf1, and Leo1 are components of the Paf1/RNA polymerase II complex
Ctr9, Rtf1, and Leo1 are components of the Paf1/RNA polymerase II complex
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DOI：
10.1128/mcb.22.7.1971-1980.2002
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发表时间：
2002-04-01
影响因子：
5.3
通讯作者：
Jaehning, JA
中科院分区：
文献类型：
--
作者：
Mueller, CL;Jaehning, JA
酿酒酵母 Paf1-RNA 聚合酶 II (Pol II) 复合物在生化和功能上与 Pol II 全酶的 Srb 介体形式不同，并且是部分基因完全表达所必需的。在这项工作中，我们使用串联亲和纯化标签来分离 Paf1 复合物，并使用质谱法来鉴定其他成分。我们已经确定 Ctr9、Rtf1 和 Leo1 是与 Paf1、Cdc73 和 Pol II 相关的因子，但与 Srb 介体无关。 PAF1 或 CTR9 的缺失会导致类似的严重多效性表型，当两种突变组合时，这些表型不会改变。相比之下，我们发现 LEO1 或 RTF1 的缺失几乎不会导致明显的表型，尽管 RTF1 的突变会抑制 TATA 结合蛋白的突变，改变转录起始位点并影响延伸。值得注意的是，LEO1 或 RTF1 的缺失会抑制许多 paf1Delta 表型。特别是，rtf1Delta paf1Delta 双突变体比 paf1Delta 单突变体生长更快，温度敏感性较低，并且对咖啡因和羟基脲具有更强的抵抗力。此外，G(1) 细胞周期蛋白 CLN1 的表达在 paf1Delta 中减少了近三倍，但在 rtf1Delta paf1Delta 双突变体中恢复到野生型水平。我们认为缺乏 Paf1 会导致复合体缺陷和转录受阻，通过去除 Leo1 或 Rtf1 可以缓解这种情况。
The Saccharomyces cerevisiae Paf1-RNA polymerase II (Pol II) complex is biochemically and functionally distinct from the Srb-mediator form of Pol II holoenzyme and is required for full expression of a subset of genes. In this work we have used tandem affinity purification tags to isolate the Paf1 complex and mass spectrometry to identify additional components. We have established that Ctr9, Rtf1, and Leo1 are factors that associate with Paf1, Cdc73, and Pol II, but not with the Srb-mediator. Deletion of either PAF1 or CTR9 leads to similar severe pleiotropic phenotypes, which are unaltered when the two mutations are combined. In contrast, we found that deletion of LEO1 or RTF1 leads to few obvious phenotypes, although mutation of RTF1 suppresses mutations in TATA-binding protein, alters transcriptional start sites, and affects elongation. Remarkably, deletion of LEO1 or RTF1 suppresses many paf1Delta phenotypes. In particular, an rtf1Delta paf1Delta double mutant grew faster, was less temperature sensitive, and was more resistant to caffeine and hydroxyurea than a paf1Delta single mutant. In addition, expression of the G(1) cyclin CLN1, reduced nearly threefold in paf1Delta, is restored to wild-type levels in the rtf1Delta paf1Delta double mutant. We suggest that lack of Paf1 results in a defective complex and a block in transcription, which is relieved by removal of Leo1 or Rtf1.