The Promoter-Proximal Pause: A Decision Point Governing RNA Polymerase II Fate

A signature feature of transcription on most genes in multicellular animals is that RNA polymerase II (RNAPII) piles up approximately 50 bases downstream of the start site at the promoter-proximal pause (PPP). Promoter-proximal pausing is controlled by positive and negative elongation factors that associate with RNAPII. There are two major outcomes for promoter-proximally paused RNAPII complexes: release into the gene body and premature termination. Here we discuss how RNAPII dynamics at the PPP function in a quality control checkpoint and in regulation of RNAPII flux through genes. We propose a pause release-attenuation model to describe RNAPII dynamics at the PPP.