A protein phosphatase functions to recycle RNA polymerase II
A protein phosphatase functions to recycle RNA polymerase II
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DOI：
10.1101/gad.13.12.1540
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发表时间：
1999-06-15
影响因子：
10.5
通讯作者：
Reinberg, D
中科院分区：
文献类型：
--
作者：
Cho, H;Kim, TK;Reinberg, D
转录受RNA聚合酶II(RNAPII)最大亚基中一个七肽重复序列的磷酸化状态的调节，该重复序列称为羧基末端结构域(CTD)。与转录起始复合体相关的RNAPII含有一个未磷酸化的CTD，而延长的聚合酶含有一个磷酸化的CTD。转录因子III-I具有由转录起始复合体刺激的CTD特有的激酶活性。在这里，我们报告了一个编码150-kD多肽的cDNA克隆，它与RNAPII一起重组了高度特异的CTD磷酸酶活性。功能分析表明，CTD磷酸酶允许RNAPII的循环。磷酸酶使CTD去磷酸化，使RNAPII有效地掺入转录起始复合体，从而导致转录增加。CTD磷酸酶在三元伸长复合体中具有活性。此外，磷酸酶通过RNAPII刺激伸长；然而，这一功能不依赖于其催化活性。
Transcription is regulated by the state of phosphorylation of a heptapeptide repeat known as the carboxy-terminal domain (CTD) present in the largest subunit of RNA polymerase II (RNAPII). RNAPII that associates with transcription initiation complexes contains an unphosphorylated CTD, whereas the elongating polymerase has a phosphorylated CTD. Transcription factor III-I has a kinase activity specific for the CTD that is stimulated by the formation of a transcription initiation complex. Here, we report the isolation of a cDNA clone encoding a 150-kD polypeptide, which, together with RNAPII, reconstitutes a highly specific CTD phosphatase activity. Functional analysis demonstrates that the CTD phosphatase allows recycling of RNAPII. The phosphatase dephosphorylates the CTD allowing efficient incorporation of RNAPII into transcription initiation complexes, which results in increased transcription. The CTD phosphatase was found to be active in ternary elongation complexes. Moreover, the phosphatase stimulates elongation by RNAPII; however, this function is independent of its catalytic activity.