PDF(Pubmed)
Abstract：
HIV-1 latency maintenance and reactivation are regulated by several viral and host factors. One such factor is Krüppel-associated box (KRAB)-associated protein 1 (KAP1: also named TRIM28 or TIF1β). While initial studies have revealed KAP1 to be a positive regulator of latency reversal in transformed and primary CD4+ T cells, subsequent studies have proposed KAP1 to be a repressor required for latency maintenance. Given this discrepancy, in this study, we re-examine KAP1 transcription regulatory functions using a chemical genetics strategy to acutely deplete KAP1 expression to avoid the accumulation of indirect effects. Notably, KAP1 acute loss partially decreased HIV-1 promoter activity in response to activating signals, a function that can be restored upon complementation with exogenous KAP1, thus revealing that KAP1-mediated activation is on target. By combining comprehensive KAP1 domain deletion and mutagenesis in a cell-based reporter assay, we genetically defined the RING finger domain and an Intrinsically Disordered Region as key activating features. Together, our study solidifies the notion that KAP1 activates HIV-1 transcription by exploiting its multi-domain protein arrangement via previously unknown domains and functions.
摘要：
HIV-1潜伏期的维持和再激活受几种病毒和宿主因子调节。一个这样的因子是Krüppel相关盒(KRAB)相关蛋白1(KAP1:也称为TRIM28或TIF1β)。虽然初步研究表明KAP1是转化和原代CD4+T细胞潜伏期逆转的正调节因子，随后的研究提出KAP1是潜伏期维持所需的抑制因子.鉴于这种差异，在这项研究中，我们使用化学遗传学策略重新检查KAP1转录调节功能,以急剧减少KAP1表达,从而避免间接效应的积累.值得注意的是,KAP1急性丢失部分降低了HIV-1启动子对激活信号的反应活性，与外源KAP1互补后可以恢复的功能，因此表明KAP1介导的激活是靶标。通过将全面的KAP1结构域缺失和诱变结合在基于细胞的报告基因测定中，我们在基因上定义了RING指域和固有无序区作为关键激活特征.一起,我们的研究巩固了KAP1通过先前未知的结构域和功能利用其多结构域蛋白排列激活HIV-1转录的观点.
