Requirements for RNA polymerase II carboxyl-terminal domain for activated transcription of human retroviruses human T-cell lymphotropic virus I and HIV-1
Requirements for RNA polymerase II carboxyl-terminal domain for activated transcription of human retroviruses human T-cell lymphotropic virus I and HIV-1
复制标题
DOI：
10.1074/jbc.271.44.27888
复制
发表时间：
1996-11-01
影响因子：
4.8
通讯作者：
Jeang, KT
中科院分区：
文献类型：
--
作者：
Chun, RF;Jeang, KT
RNA聚合酶II（RNAP II）的羧基末端结构域（CTD）含有多个重复序列，共有七个肽：Tyr-Ser-Pro-Thr-Ser-Pro-Ser。然而，并非所有转录的启动子都需要具有全长CTD的RNAP II。此外，不同的激活剂可以有效地促进CTD中缺失的聚合酶II突变体的转录活性。因此，RNAP II CTD在转录和响应激活剂中的作用仍不完全清楚。为了研究CTD在人逆转录病毒人T细胞嗜淋巴细胞病毒I和人免疫缺陷病毒1的调节性转录中的作用，我们使用先前开发的α-鹅膏蕈碱抗性系统（Gerber，H. P.，Hagmann，M.，Seipel，K.，Georgiev，O.，西，M。一、Litingtung，Y.，Schaffner，W.，和Corden，J. L.（1995）Nature 374，660-662）。我们发现，由人T细胞嗜淋巴细胞病毒I激活蛋白Tax指导的转录强烈促进CTD缺陷型RNA聚合酶II。相比之下，人类免疫缺陷病毒1型激活因子达特通过与新生前导RNA连接而被募集到启动子中，需要含有CTD的聚合酶II来实现转录活性。生物化学上，我们的特点是，达特与细胞CTD激酶活性，而税收没有。一致地，我们发现，细胞转录因子Sp1，它可以激活CTD缺陷的聚合酶II的效率类似于税收，也未能结合CTD激酶。总之，这些观察结果解决了具有（外）连接的CTD激酶的激活剂与具有（外）CTD的RNA聚合酶II部分调节的转录之间的机械推论。
The carboxyl-terminal domain (CTD) of RNA polymerase (RNAP) II contains multiple repeats with a heptapeptide consensus: Tyr-Ser-Pro-Thr-Ser-Pro-Ser. It has been proposed that phosphorylation of this CTD facilitates clearance and elongation of transcription complexes initiated at the promoters. However, not all transcribed promoters require RNAP II with full-length CTD. Furthermore, different activators can promote capably the transcriptional activity of polymerase II mutants deleted in the CTD. Thus, the role of the RNAP II CTD in transcription and in response to activators remains incompletely understood. To study the role of CTD in the regulated transcription of human retroviruses human-T cell lymphotropic virus I and human immunodeficiency virus 1, we used an alpha-amanitin-resistant system developed previously (Gerber, H. P., Hagmann, M., Seipel, K., Georgiev, O., West, M. A., Litingtung, Y., Schaffner, W., and Corden, J. L. (1995) Nature 374, 660-662). We found that transcription directed by the human T-cell lymphotropic virus I activator protein Tax was strongly promoted by CTD-deficient RNA polymerase II. By contrast, the human immunodeficiency virus 1 activator Tat, which is recruited to the promoter by tethering to a nascent leader RNA, requires CTD-containing polymerase II for transcriptional activity. Biochemically, we characterized that Tat associated with a cellular CTD kinase activity, whereas Tax did not. Concordantly, we found that cellular transcription factor Sp1, which can activate CTD-deficient polymerase II with an efficiency similar to Tax, also failed to bind a CTD kinase. Taken together, these observations address mechanistic corollaries between activators with(out) a linked CTD kinase and regulated transcription by RNA polymerase II moieties with(out) a CTD.