The Integrator Complex Recognizes a New Double Mark on the RNA Polymerase II Carboxyl-terminal Domain
The Integrator Complex Recognizes a New Double Mark on the RNA Polymerase II Carboxyl-terminal Domain
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DOI：
10.1074/jbc.m110.132530
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发表时间：
2010-07-02
影响因子：
4.8
通讯作者：
Murphy, Shona
中科院分区：
文献类型：
--
作者：
Egloff, Sylvain;Szczepaniak, Sylwia Anna;Murphy, Shona
RNA聚合酶II（pol II）的最大亚基的羧基末端结构域（CTD）包含七肽Tyr（1）-Ser（2）-Pro（3）-Thr（4）-Ser（5）-Pro（6）-Ser（7）的多个串联重复。这种不寻常的结构作为pol II转录基因表达所需的因子结合的平台，包括小核RNA（snRNA）基因特异性整合子复合物。pol II CTD特异性介导整合子向snRNA基因启动子的募集，以激活转录并指导转录物的3'端加工。CTD的磷酸化和7位的丝氨酸是整合子募集所必需的。在这里，我们进一步研究了CTD七肽中丝氨酸的需求及其磷酸化对整合剂结合的影响。我们发现CTD的Ser（2）和Ser（7）都是必需的，并且这些残基的磷酸化对于有效结合是必要的和足够的。使用合成的磷酸肽，我们已经确定了整合剂与CTD相互作用所需的最小Ser（2）/Ser（7）双磷酸化标记的模式。这种新的双磷酸化标记是CTD代码功能库的新补充，可能是snRNA基因表达的特异性信号。
The carboxyl-terminal domain (CTD) of the largest subunit of RNA polymerase II (pol II) comprises multiple tandem repeats of the heptapeptide Tyr(1)-Ser(2)-Pro(3)-Thr(4)-Ser(5)-Pro(6)-Ser(7). This unusual structure serves as a platform for the binding of factors required for expression of pol II-transcribed genes, including the small nuclear RNA (snRNA) gene-specific Integrator complex. The pol II CTD specifically mediates recruitment of Integrator to the promoter of snRNA genes to activate transcription and direct 3' end processing of the transcripts. Phosphorylation of the CTD and a serine in position 7 are necessary for Integrator recruitment. Here, we have further investigated the requirement of the serines in the CTD heptapeptide and their phosphorylation for Integrator binding. We show that both Ser(2) and Ser(7) of the CTD are required and that phosphorylation of these residues is necessary and sufficient for efficient binding. Using synthetic phosphopeptides, we have determined the pattern of the minimal Ser(2)/Ser(7) double phosphorylation mark required for Integrator to interact with the CTD. This novel double phosphorylation mark is a new addition to the functional repertoire of the CTD code and may be a specific signal for snRNA gene expression.