Ping Y H, Rana T M
Department of Pharmacology, Robert Wood Johnson Medical School, and Molecular Biosciences Graduate Program at Rutgers University, Piscataway, New Jersey 08854, USA.
J Biol Chem. 1999 Mar 12;274(11):7399-404. doi: 10.1074/jbc.274.11.7399.
Human immunodeficiency virus, type 1 (HIV-1) Tat protein activates transcription from the HIV-1 long terminal repeat. Tat interacts with TFIIH and Tat-associated kinase (a transcription elongation factor P-TEFb) and requires the carboxyl-terminal domain of the largest subunit of RNA polymerase II (pol II) for transactivation. We developed a stepwise RNA pol II walking approach and used Western blotting to determine the role of TFIIH and P-TEFb in HIV-1 transcription elongation. Our results demonstrate the new findings that P-TEFb is a component of the preinitiation complex and travels with the elongating RNA pol II, whereas TFIIH is released from the elongation complexes before the trans-activation responsive region RNA is synthesized. Our results suggest that TFIIH and P-TEFb are involved in the clearance of promoter-proximal pausing of RNA pol II on the HIV-1 long terminal repeat at different stages.
1型人类免疫缺陷病毒（HIV-1）的Tat蛋白可激活HIV-1长末端重复序列的转录。Tat与TFIIH及Tat相关激酶（一种转录延伸因子P-TEFb）相互作用，并且反式激活需要RNA聚合酶II（pol II）最大亚基的羧基末端结构域。我们开发了一种逐步的RNA pol II步移方法，并使用蛋白质免疫印迹法来确定TFIIH和P-TEFb在HIV-1转录延伸中的作用。我们的结果证明了新的发现，即P-TEFb是起始前复合物的一个组成部分，并与延伸中的RNA pol II一起移动，而TFIIH在反式激活应答区域RNA合成之前从延伸复合物中释放。我们的结果表明，TFIIH和P-TEFb在不同阶段参与了RNA pol II在HIV-1长末端重复序列上启动子近端暂停的清除。
