The release of a paused Pol II depends on the recruitment of P-TEFb. Recent studies showed that both active P-TEFb and inactive P-TEFb (7SK snRNP) can be recruited to the promoter regions of global genes by different mechanisms. Here, we summarize the recent advances on these distinct recruitment mechanisms.
Keywords: 7SK snRNP; Brd4; KAP1; P-TEFb; RNA Pol II; SEC; promoter-proximal pausing; transcription elongation.