Transcription mechanisms that contribute to HIV-1 latency

描述（由申请人提供）：HIV前病毒在转录水平受到调控，涉及转录起始、染色质组织和延伸的变化。特别是，转录延伸已被证明是HIV表达的限制步骤。我们假设，RNA聚合酶II的持续合成能力和过早的转录终止加上染色质重塑的协调控制，创造了一个关键的检查点，限制了前病毒的转录，并直接影响艾滋病毒在不同的细胞和分子环境中的潜伏期。我们已经表明，RNA聚合酶II的持续合成能力是HIV转录的一个检查点，NELF，一个暂停RNA聚合酶II的因子，通过招募终止因子Pcf 11和转录辅阻遏物到HIV-1长末端重复序列来重新抑制HIV前病毒。使用各种生化方法，包括染色质免疫沉淀，RNAPII足迹，体外转录系统和质谱，我们建议确定的生化机制和表征的细胞因子，负调控HIV转录延长。这些研究将为HIV潜伏期的建立、维持和逆转提供新的见解。了解HIV转录延长的调节将为控制和清除不同细胞库中的HIV提供新的细胞靶点。

DESCRIPTION (provided by applicant): HIV provirus is regulated at the level of transcription and involves changes in transcription initiation, chromatin organization and elongation. In particular, transcription elongation has been demonstrated to be a limiting step for HIV expression. We hypothesize that the coordinated control of RNA polymerase II processivity and premature transcription termination coupled with chromatin remodeling creates a key checkpoint that limits provirus transcription and directly impact HIV latency in different cellular and molecular contexts. We have shown that RNA polymerase II processivity is a check point for HIV transcription and that NELF, a factor that pauses RNA polymerase II, re-enforces repression of HIV proviruses by recruiting a termination factor Pcf11 and transcriptional corepressors to the HIV-1 long terminal repeat. Using a variety of biochemical approaches, including chromatin immunoprecipitation, RNAPII footprinting, in vitro transcription systems and mass spectrometry, we propose to determine the biochemical mechanisms and characterize the cellular factors that negatively regulate HIV transcription elongation. These studies will provide new insights into the establishment, maintenance and reversal of HIV latency. Understanding the regulation of HIV transcription elongation will provide novel cellular targets for controlling and purging HIV in different cellular reservoirs.