title: Inhibition of post-transcriptional RNA processing by CDK inhibitors and its implication in anti-viral therapy.
abstract: Cyclin-dependent kinases (CDKs) are key regulators of the cell cycle and RNA polymerase II mediated transcription. Several pharmacological CDK inhibitors are currently in clinical trials as potential cancer therapeutics and some of them also exhibit antiviral effects. Olomoucine II and roscovitine, purine-based inhibitors of CDKs, were described as effective antiviral agents that inhibit replication of a broad range of wild type human viruses. Olomoucine II and roscovitine show high selectivity for CDK7 and CDK9, with important functions in the regulation of RNA polymerase II transcription. RNA polymerase II is necessary for viral transcription and following replication in cells. We analyzed the effect of inhibition of CDKs by olomoucine II on gene expression from viral promoters and compared its effect to widely-used roscovitine. We found that both roscovitine and olomoucine II blocked the phosphorylation of RNA polymerase II C-terminal domain. However the repression of genes regulated by viral promoters was strongly dependent on gene localization. Both roscovitine and olomoucine II inhibited expression only when the viral promoter was not integrated into chromosomal DNA. In contrast, treatment of cells with genome-integrated viral promoters increased their expression even though there was decreased phosphorylation of the C-terminal domain of RNA polymerase II. To define the mechanism responsible for decreased gene expression after pharmacological CDK inhibitor treatment, the level of mRNA transcription from extrachromosomal DNA was determined. Interestingly, our results showed that inhibition of RNA polymerase II C-terminal domain phosphorylation increased the number of transcribed mRNAs. However, some of these mRNAs were truncated and lacked polyadenylation, which resulted in decreased translation. These results suggest that phosphorylation of RNA polymerase II C-terminal domain is critical for linking transcription and posttrancriptional processing of mRNA expressed from extrachromosomal DNA.
authors.affiliation: Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic.
authors.forename: Jitka
authors.initials: J
authors.lastname: Holcakova
authors.affiliation: Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Muller
authors.affiliation: School of Medicine, Cardiff University, Cardiff, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Tomasec
authors.affiliation: Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic.
authors.forename: Roman
authors.initials: R
authors.lastname: Hrstka
authors.affiliation: Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic.
authors.forename: Marta
authors.initials: M
authors.lastname: Nekulova
authors.affiliation: Laboratory of Growth Regulators, Faculty of Science, Palacky University, Olomouc, Czech Republic ; Institute of Experimental Botany AS CR, Olomouc, Czech Republic.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Krystof
authors.affiliation: Laboratory of Growth Regulators, Faculty of Science, Palacky University, Olomouc, Czech Republic ; Institute of Experimental Botany AS CR, Olomouc, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Strnad
authors.affiliation: School of Medicine, Cardiff University, Cardiff, United Kingdom.
authors.forename: Gavin W G
authors.initials: GW
authors.lastname: Wilkinson
authors.affiliation: Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic.
authors.forename: Borivoj
authors.initials: B
authors.lastname: Vojtesek
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000187:drug effects*; D002460:Cell Line; D002522:Chlorocebus aethiops; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D004279:DNA, Viral; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011687:Purines / Q000494:pharmacology; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional / Q000187:drug effects*; D000077546:Roscovitine
chemical_list: D004279:DNA, Viral; D047428:Protein Kinase Inhibitors; D011687:Purines; C475587:olomoucine II; D000077546:Roscovitine; D018844:Cyclin-Dependent Kinases; D012319:RNA Polymerase II