Crosstalk between mRNA 3' end processing and transcription initiation
Résumé
Transcription and mRNA maturation are interdependent events. Although stimulatory connections between these processes within the same round of transcription are well described, functional coupling between separate transcription cycles remains elusive. Comparing time-resolved transcription profiles of single-copy integrated beta-globin gene variants, we demonstrate that a polyadenylation site mutation decreases transcription initiation of the same gene. Upon depletion of the 3' end processing and transcription termination factor PCF11, endogenous genes exhibit a similar phenotype. Readthrough RNA polymerase II (RNAPII) engaged on polyadenylation site-mutated transcription units sequester the transcription initiation/elongation factors TBP, TFIIB and CDK9, leading to their depletion at the promoter. Additionally, high levels of TBP and TFIIB appear inside the gene body, and Ser2-phosphorylated RNAPII accumulates at the promoter. Our data demonstrate that 3' end formation stimulates transcription initiation and suggest that coordinated recycling of factors from a gene terminator back to the promoter is essential for sustaining continued transcription.
Mots clés
Base Sequence Cyclin-Dependent Kinase 9/metabolism HEK293 Cells Humans Models
Biological Molecular Sequence Data Phenotype Phosphorylation Phosphoserine/metabolism Point Mutation/genetics Poly A/genetics Promoter Regions
Genetic mRNA Cleavage and Polyadenylation Factors/metabolism
Genetic/genetics RNA 3' End Processing/*genetics RNA Polymerase II/metabolism RNA Splicing/genetics RNA
Messenger/genetics/*metabolism TATA-Box Binding Protein/metabolism Time Factors *Transcription