Investigating the links between transcription and mRNA 3' end processing

RNA Polymerase II (Pol II) is responsible for transcribing all protein coding genes and some non-coding genes. Protein-coding mRNAs undergo extensive processing during Pol II transcription in order to become functional molecules. This includes 5’capping, splicing and 3’end cleavage and polyadenylation. mRNA processing is coordinated by the phosphorylation of the Pol II carboxy-terminal domain (CTD) and has been shown to be affected by transcription rate. However, the molecular mechanisms underpinning regulation of mRNA processing by transcription are not well understood. Here, I aim to address this by establishing an in vitro system which allows to the study of processes linked to transcription such as mRNA 3’ end processing. The work presented here contains detailed studies of Pol II Rpb1 mutants that show opposite effects in RNA processivity and transcription rate using an in vitro transcription system and state-of-the-art in vivo approaches such as PRO-seq (in collaboration with the postdoctoral visitor), studying how transcription rate contributes to the ability of Pol II to interact with factors and reconstitution of the 3’ mRNA processing machinery that is involved in cleavage and polyadenylation