Project description:The current model is that the influenza virus polymerase (FluPol) binds either to host RNA polymerase II (RNAP II) or to the acidic nuclear phosphoprotein 32 (ANP32), which drives its conformation and activity towards transcription or replication of the viral genome, respectively. Here, we provide evidence that the FluPol-RNAP II binding interface, beyond its well-acknowledged function in cap-snatching during transcription initiation, has also a pivotal role in replication of the viral genome. Using a combination of cell-based and in vitro approaches, we show that the RNAP II C-terminal-domain, jointly with ANP32, enhances FluPol replication activity. We observe successive conformational changes to switch from a transcriptase to a replicase conformation in the presence of the bound RNPAII C-terminal domain and propose a model in which the host RNAP II is the anchor for transcription and replication of the viral genome. Our data open new perspectives on the spatial coupling of viral transcription and replication and the coordinated balance between these two activities.
Project description:The phosphorylation and dephosphorylation of transcription machinery are essential for the precise control of gene expression. A non-canonical protein phosphatase 2A (PP2A) holoenzyme (denoted INTAC), in which the 14-subunit Integrator recruits RNA polymerase II (Pol II) and the PP2A core enzyme dephosphorylates the C-terminal repeat domain (CTD) of Pol II at Serine-5 and Serine-2.
Project description:Methylation of histone H3 lysine 4 (H3K4) by the Set1/COMPASS complex is coupled with active transcription, and this modification is important for regulating gene expression. Set1/COMPASS associates with the RNA polymerase II (RNApII) C-terminal domain (CTD) to establish proper levels and distribution of H3K4 methylations.To ask how the Set1-RNApII CTD binding affects the occupancy and overall level of H3K4 methylations, ChIP-Seq was pefromed in cells transformed with full length or N-terminal truncated Set1. Our results indicate that Set1-RNApII CTD interaction is necessary for maintaining H3K4 methylations throughout the genes.
Project description:The Carboxy-terminal domain (CTD) of RNA Polymerase II (RNAPII) in mammals undergoes extensive post-translational modification, which is essential for transcriptional initiation and elongation. Here, we show that the CTD of RNAPII is methylated at a single arginine (R1810) by the transcriptional co-activator CARM1. Although methylation at R1810 is present on the hyper-phosphorylated form of RNAPII in vivo, Ser-2 or Ser-5 phosphorylation inhibit CARM1 activity towards this site in vitro, suggesting that methylation occurs before transcription initiation. Mutation of R1810 results in the mis-expression of a variety of snRNAs and snoRNAs, an effect that is also observed in Carm1-/- MEFs. These results demonstrate that CTD methylation facilitates the expression of select RNAs, perhaps serving to discriminate the RNAPII-associated machinery recruited to distinct gene types. To address the function of RNAPII methylation, we generated Raji cell lines expressing an RNA Polymerase II resistant to α-amanitin and carrying either wild-type R1810 or an arginine to alanine substitution at that same residue, abolishing R1810 methylation of the CTD. In cells cultured in α-amanitin, the α-amanitin-resistant mutants fully replaced the functions of endogenous RNAPII, allowing us to study if gene-expression is affected by the absence of R1810me
Project description:We obtained RNA polymerase II occupancy profiles across the genome of S.cerevisiae strains: Abf1 anchor-away cells after addition of rapamycin for different time points (including no addition of rapamycin) and Rap1-AID auxin-degron cells after addition of auxin for different time points (including no addition of auxin) . This allowed us to compare polymerase occupancy profiles when these proteins are depleted from the nucleus or degraded.
Project description:Cyclin-dependent kinase 12 (CDK12) phosphorylates the carboxyl-terminal domain (CTD) of RNA polymerase II (pol II) but its roles in transcription beyond the expression of DNA damage response genes remain unclear. Here, we have used TT-seq and mNET-seq to monitor the direct effects of rapid CDK12 inhibition on transcription activity and CTD phosphorylation in human cells. CDK12 inhibition causes a genome-wide defect in transcription elongation and a global reduction of CTD Ser2 and Ser5 phosphorylation. The elongation defect is explained by the loss of the elongation factors LEO1 and CDC73, part of PAF1 complex, and SPT6 from the newly-elongating pol II. Our results indicate that CDK12 is a general activator of pol II transcription elongation and indicate that it targets both Ser2 and Ser5 residues of the pol II CTD.