TFⅡH参与调控RNA聚合酶Ⅱ介导的mRNA转录的研究进展

Advances in studies of TFⅡH in the regulation of RNA polymerase Ⅱ mediated mRNA transcription

通用转录因子TFⅡH(transcription factorⅡH)在RNA聚合酶Ⅱ(RNA PolⅡ)介导mRNA的转录中起着非常重要的作用,且主要是通过磷酸化RNA PolⅡ大亚基的羧基末端结构域(CTD)的各个位点来调控转录过程。转录启动前,TFⅡH及其他转录因子与RNA PolⅡ结合形成转录起始前复合物(preinitiation complex,PIC),而后TFⅡH的亚基CAK通过磷酸化RNAPⅡCTD的第五位丝氨酸(Ser5)和第七位丝氨酸(Ser7)促进转录的起动。而CAK磷酸化Ser5的同时也能够促使另一个激酶CDK9磷酸化RNAPⅡCTD的第二位丝氨酸(Ser2),该过程参与调控转录的延伸以及终止。

TF Ⅱ H （transcription factor Ⅱ H） plays an essential role in the mRNA transcription mediated by RNA polymerase [[ （RNA Pol Ⅱ ） and mainly regulated by the phosphorylation of several sites of RNA Pol Ⅱ C-terminal domain （CTD）. Before the initiation of transcription,TF Ⅱ H and other transcriptional factors integrate with RNA Pol Ⅱ and then form a preinitiation complex （PIC）. The initiation of transcription is promoted by RNA Pol Ⅱ CTD Serine-5 and Ser- ine-7 which are phosphorylated by TF Ⅱ H subunit CAK. The phosphorylation of Serine-5 by CAK also triggeres the other kinase CDK9 to phosphorylate RNA Pol Ⅱ CTD Serine-2. Further- ly,the phosphorylation of RNA Pol Ⅱ CTD Serine-2 participats in the extension and termination of mRNA transcription.