“…Both cellular activators and Tat promote proviral transcription in the host and viral phases, respectively, through a complex layer of host factors including general transcription factors, RNA polymerase II (Pol II), co-activators/co-repressors, and chromatin-modifying enzymes, among others (Ott et al, 2011;Van Lint et al, 2013). One key host factor is the positive transcription elongation factor b (the P-TEFb kinase) (Dalal and Johnson, 2017;Wei et al, 1998), which is composed of a cyclin T subunit and the catalytic CDK9 subunit (hereafter referred as CDK9). Both cellular activators and Tat utilize CDK9 to facilitate the transcription elongation program, a critical step in the viral life cycle (Mancebo et al, 1997;Ott et al, 2011;Peterlin and Price, 2006;Zhou et al, 2000).…”