Fig. 1

RNA transcription and processing. a Transcription of RNA is initiated from a promoter sequence (indicated in red) within the genome. Ribonucleoside triphosphate polymerisation results in a 5′ triphosphate at the 5′ end of the nascent transcript and a 3′ hydroxyl at its 3′ terminus. b mRNAs can be internally cleaved by endonucleases to yield two RNA fragments or can be degraded by exonucleases from either their 5′ or 3′ termini. The activity of exonucleases is often triggered by the selective dephosphorylation of a terminal triphosphate to a monophosphate by a pyrophosphatase. c This study focuses on all RNA processing events that result in either a 5′ triphosphate (dRNA-Seq) or 5′ monophosphate (pRNA-Seq) and that simultaneously contain a terminal 3′ hydroxyl