Fig. 5: Model of co-transcriptional cap snatching.
From: Mechanism of co-transcriptional cap snatching by influenza polymerase
Capping enzymes, including CMTR1, synthesize the cap(1) structure on the RNA co-transcriptionally. After capping is finished, CMTR1 dissociates from Pol II. The resulting Pol II–DSIF elongation complex with a capped RNA is a substrate for cap snatching and is bound by FluPol. Then, the FluPol endonuclease cleaves the RNA, and FluPol may dissociate from the Pol II elongation complex surface and initiates viral transcription, whereas Pol II gets terminated.
