title: A locus encompassing the Epstein-Barr virus bglf4 kinase regulates expression of genes encoding viral structural proteins.
abstract: The mechanism regulating expression of late genes, encoding viral structural components, is an unresolved problem in the biology of DNA tumor viruses. Here we show that BGLF4, the only protein kinase encoded by Epstein-Barr virus (EBV), controls expression of late genes independent of its effect on viral DNA replication. Ectopic expression of BGLF4 in cells lacking the kinase gene stimulated the transcript levels of six late genes by 8- to 10-fold. Introduction of a BGLF4 mutant that eliminated its kinase activity did not stimulate late gene expression. In cells infected with wild-type EBV, siRNA to BGLF4 (siG4) markedly reduced late gene expression without compromising viral DNA replication. Synthesis of late products was restored upon expression of a form of BGLF4 resistant to the siRNA. Studying the EBV transcriptome using mRNA-seq during the late phase of the lytic cycle in the absence and presence of siG4 showed that BGLF4 controlled expression of 31 late genes. Analysis of the EBV transcriptome identified BGLF3 as a gene whose expression was reduced as a result of silencing BGLF4. Knockdown of BGLF3 markedly reduced late gene expression but had no effect on viral DNA replication or expression of BGLF4. Our findings reveal the presence of a late control locus encompassing BGLF3 and BGLF4 in the EBV genome, and provide evidence for the importance of both proteins in post-replication events that are necessary for expression of late genes.
authors.affiliation: Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, United States of America.
authors.forename: Ayman
authors.initials: A
authors.lastname: El-Guindy
authors.affiliation: Yale Center for Genome Analysis (YCGA), Yale University, West Haven, Connecticut, United States of America.
authors.forename: Francesc
authors.initials: F
authors.lastname: Lopez-Giraldez
authors.affiliation: Department of Tumor Virology, German Cancer Research Center, Im Neuenheimer Feld, Heidelberg, Germany.
authors.forename: Henri-Jacques
authors.initials: HJ
authors.lastname: Delecluse
authors.affiliation: Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, United States of America.
authors.forename: Jessica
authors.initials: J
authors.lastname: McKenzie
authors.affiliation: Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, United States of America; Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut, United States of America; Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut, United States of America.
authors.forename: George
authors.initials: G
authors.lastname: Miller
mesh_terms: D015152:Blotting, Northern; D015967:Gene Expression Regulation, Viral / Q000235:genetics*; D056426:Genetic Loci; D057809:HEK293 Cells; D006801:Humans; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis* / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D014162:Transfection; D014764:Viral Proteins / Q000096:biosynthesis* / Q000235:genetics*; D015678:Viral Structural Proteins / Q000096:biosynthesis* / Q000235:genetics*; D014779:Virus Replication / Q000235:genetics
chemical_list: D014764:Viral Proteins; D015678:Viral Structural Proteins; C406063:BGLF4 protein, Epstein-Barr virus; D017346:Protein Serine-Threonine Kinases