EBV EBNA 2 stimulates CDK9-dependent transcription and RNA polymerase II phosphorylation on serine 5.
EBNA 2 is one of only five viral genes essential for the infection and immortalization of human B cells by the cancer-associated virus Epstein-Barr virus (EBV). EBNA 2 activates cellular and viral transcription and associates with components of the basal transcription apparatus and a number of coactivators. We provide the first evidence to show that the mechanism of transcriptional activation by EBNA 2 also involves phosphorylation of the C-terminal domain (CTD) of RNA polymerase II (pol II). We found that transcriptional activation by EBNA 2 was inhibited by a dominant-negative mutant of the pol II CTD kinase, CDK9, and by low concentrations of the CDK9 inhibitor 5, 6-dichloro-1-beta-D-ribofuranosylbenzimidazole. Moreover, using chromatin immunoprecipitation assays we demonstrated that EBNA 2 stimulates both pol II recruitment and pol II phosphorylation on serine 5 of the CTD in vivo. These results identify a new step in the transcription cycle that is subject to regulation by a key EBV-encoded transcription factor and highlight CDK9 inhibitors as potential anti-EBV agents.
Bark-Jones
S J
SJ
Department of Biochemistry, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK.
Webb
H M
HM
West
M J
MJ
D000429:Alcohol Oxidoreductases; D000818:Animals; D015153:Blotting, Western; D042863:Cyclin-Dependent Kinase 9 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019309:Epstein-Barr Virus Nuclear Antigens / Q000378:metabolism*; D004854:Herpesvirus 4, Human / Q000502:physiology; D006801:Humans; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D012319:RNA Polymerase II / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012694:Serine / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014764:Viral Proteins
D004268:DNA-Binding Proteins; C402641:EBNA-2 protein, Human herpesvirus 4; D004791:Enzyme Inhibitors; D019309:Epstein-Barr Virus Nuclear Antigens; D010750:Phosphoproteins; D014764:Viral Proteins; D012694:Serine; D000429:Alcohol Oxidoreductases; C096794:C-terminal binding protein; D042863:Cyclin-Dependent Kinase 9; D012319:RNA Polymerase II