The PAF1 complex promotes 3‘ processing of pervasive transcripts

The PAF1 complex (PAF1C) functions in multiple transcriptional processes involving RNA Polymerase II (Pol II). eRNAs and PROMPTs are pervasive transcripts transcribed by Pol II and rapidly degraded by the nuclear exosome complex after 3’ endonucleolytic cleavage by the Integrator complex (Integrator). Here we show that PAF1C has an unexpected role in the termination of eRNAs and PROMPTs that are cleaved 1-3 kb downstream of the transcription start site. Mechanistically, PAF1C facilitates recruitment of Integrator to sites of pervasive transcript cleavage, promoting timely cleavage and transcription termination. We also show that PAF1C recruits Integrator to coding genes, where PAF1C then dissociates from Integrator upon entry into processive elongation. Our results demonstrate an unexpected function for PAF1C in limiting the length and accumulation of pervasive transcripts that result from nonproductive transcription