Opposing effects of Ctk1 kinase and Fcp1 phosphatase at Ser 2 of the RNA polymerase II C-terminal domain
Opposing effects of Ctk1 kinase and Fcp1 phosphatase at Ser 2 of the RNA polymerase II C-terminal domain
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DOI：
10.1101/gad.935901
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发表时间：
2001-12-15
影响因子：
10.5
通讯作者：
Buratowski, S
中科院分区：
文献类型：
--
作者：
Cho, EJ;Kobor, MS;Buratowski, S
RNA聚合酶II（Pol II）最大亚基的C-末端结构域（CTD）在转录过程中过度磷酸化。使用体内交联/染色质免疫沉淀试验，我们发现以前，不同的磷酸化形式的RNA Pol II占主导地位，在不同的转录阶段。在启动子处，Pol II CTD在Ser 5处被基础转录因子TFIIH磷酸化。然而，在编码区中，CTD主要在Ser 2处磷酸化。在这里，我们表明，延伸相关的丝氨酸2磷酸化依赖于Ctk 1激酶，一个假定的酵母同源物Cdk 9/P-TEFb。此外，Fcp 1 CTD磷酸酶的突变导致Ser 2磷酸化水平增加。Ctk 1和Fcp 1都与启动子和编码区交联，表明它们与延伸聚合酶相关。Ctk 1和Fcp 1都参与了转录延伸的调节。我们的研究结果表明，这种调节可能发生通过调节丝氨酸2磷酸化水平，这反过来，可能会调节延伸因子与聚合酶的关联。
The C-terminal domain (CTD) of the RNA polymerase II (Pol II) largest subunit is hyperphosphorylated during transcription. Using an in vivo cross-linking/chromatin immunoprecipitation assay, we found previously that different phosphorylated forms of RNA Pol II predominate at different stages of transcription. At promoters, the Pol II CTD is phosphorylated at Ser 5 by the basal transcription factor TFIIH. However, in coding regions, the CTD is predominantly phosphorylated at Ser 2. Here we show that the elongation-associated phosphorylation of Ser 2 is dependent upon the Ctk1 kinase, a putative yeast homolog of Cdk9/P-TEFb. Furthermore, mutations in the Fcp1 CTD phosphatase lead to increased levels of Ser 2 phosphorylation. Both Ctk1 and Fcp1 cross-link to promoter and coding regions, suggesting that they associate with the elongating polymerase. Both Ctk1 and Fcp1 have been implicated in regulation of transcription elongation. Our results suggest that this regulation may occur by modulating levels of Ser 2 phosphorylation, which in turn, may regulate the association of elongation factors with the polymerase.