Post‐transcriptional Processing at the Promoter Proximal RNA Polymerase II Pausing. A Possible Mechanism for Premature Termination

Promoter‐proximal RNA Polymerase II pausing, which occurs within the first 100 nucleotides of a gene, refers to a property of the Polymerase II to halt transcription temporarily but remain transcriptionally competent. Knowledge of proximally paused Polymerase II dynamics is important for understanding the regulation of mRNA production.At the paused site, Polymerase II can either elongate to resume mRNA synthesis or terminate to release a short RNA. We hypothesize that both events occur on genes and, furthermore, suggest that the equilibrium between elongation rate and termination rate at the pause site reflects regulatory inputs at the promoter.We adopted the small RNA sequencing approach to detect short RNA generated by paused Pol II genome‐wide on chromatin. Analysis of short RNA in subcellular fractions revealed genes that display RNA species with a 5′ monophosphate ends downstream of transcription start sites. The 3′ ends of these monophosphate RNAs reside within the location of the 3′ ends of RNAs from paused Polymerase II demonstrating they may be products of paused Polymerase II. Short RNAs generated by Paused Pol II may represent a novel class of small RNAs derived from promoter‐proximal transcription termination. Future experiments will focus on identity and functional roles of these transcripts.Support or Funding InformationNIH COBRE P20GM104360NIH R21CA217751This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.