Phospho-carboxyl-terminal domain binding and the role of a prolyl isomerase in pre-mRNA 3′-end formation
Phospho-carboxyl-terminal domain binding and the role of a prolyl isomerase in pre-mRNA 3′-end formation
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DOI：
10.1074/jbc.274.44.31583
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发表时间：
1999-10-29
影响因子：
4.8
通讯作者：
Greenleaf, AL
中科院分区：
文献类型：
--
作者：
Morris, DP;Phatnani, HP;Greenleaf, AL
用酵母CTD激酶I和RNA聚合酶II的CTD亲和层析柱鉴定Ess1/Pin1为磷酸化CTD结合蛋白。Ess1/Pin1是一种参与有丝分裂调节和Pre-mRNA3‘-端形成的多肽基-脯氨酰异构酶。像天然的Ess1一样，GST-Ess1融合蛋白与磷酸化的CTD特异性结合，而不与非磷酸化的CTD结合。此外，过度磷酸化的RNA聚合酶II似乎是酵母总抽提物中主要的Ess1结合蛋白。我们证明，磷酸化CTD结合是由Ess1的小WW结构域而不是异构酶结构域介导的。这些发现提示了一种机制，其中WW结构域与延长的RNA聚合酶II的磷酸化的CTD结合，而异构酶结构域通过异构化Pro残基来重新配置CTD，可能是通过一种过程机制。这一过程可能与使用磷酸化的CTD的多种前信使核糖核酸成熟事件有关，包括前信使核糖核酸S末端形成和转录终止的耦合过程。
A phospho-carboxyl-terminal domain (CTD) affinity column created with yeast CTD kinase I and the CTD of RNA polymerase II was used to identify Ess1/Pin1 as a phospho-CTD-binding protein. Ess1/Pin1 is a peptidyl prolyl isomerase involved in both mitotic regulation and pre-mRNA 3'-end formation. Like native Ess1, a GST-Ess1 fusion protein associates specifically with the phosphorylated but not with the unphosphorylated CTD. Further, hyperphosphorylated RNA polymerase II appears to be the dominant Ess1 binding protein in total yeast extracts. We demonstrate that phospho-CTD binding is mediated by the small WW domain of Ess1 rather than the isomerase domain. These findings suggest a mechanism in which the WW domain binds the phosphorylated CTD of elongating RNA polymerase II and the isomerase domain reconfigures the CTD though isomerization of proline residues perhaps by a processive mechanism. This process may be linked to a variety of pre-mRNA maturation events that use the phosphorylated CTD, including the coupled processes of pre-mRNA S'-end formation and transcription termination.