title: Up-regulation of Murid herpesvirus 4 ORF50 by hypoxia: possible implication for virus reactivation from latency.
abstract: Murid herpesvirus 4 (MuHV-4) is a member of the Gammaherpesvirus subfamily capable to establish a long-lasting latency and induce occasional malignancies. Because MuHV-4 is associated with cancer in a subset of virus-infected mice and because tumor development is often linked with hypoxia, we studied the influence of hypoxia on the biology of this virus. Using immunofluorescence and FACS analysis we detected increased proportion of MuHV-4 positive cells in the latently infected NB-78 cell line exposed to low oxygen conditions compared to normoxic controls. Moreover, the expression of ORF50, a crucial gene responsible for switch from latency to lytic virus replication, was induced upon the exposure of NB-78 cells to hypoxia. Luciferase reporter assays with ORF50 promoter confirmed the hypoxia-dependent induction. Transient co-transfections with hypoxia inducible factors showed that HIF-2alpha is a more potent activator of ORF50 expression than HIF-1alpha. Our results confirm that the MuHV-4 life cycle is influenced by low oxygen concentration.
authors.affiliation: Institute of Virology, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovak Republic.
authors.forename: Katarina
authors.initials: K
authors.lastname: Polcicova
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Hrabovska
authors.forename: Jela
authors.initials: J
authors.lastname: Mistrikova
authors.forename: Jana
authors.initials: J
authors.lastname: Tomaskova
authors.forename: Jaromir
authors.initials: J
authors.lastname: Pastorek
authors.forename: Silvia
authors.initials: S
authors.lastname: Pastorekova
authors.forename: Juraj
authors.initials: J
authors.lastname: Kopacek
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D015967:Gene Expression Regulation, Viral; D017930:Genes, Reporter; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D051379:Mice; D016366:Open Reading Frames; D010100:Oxygen / Q000378:metabolism* / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D018144:Rhadinovirus / Q000235:genetics / Q000502:physiology*; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation; D014775:Virus Activation; D017735:Virus Latency; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D000956:Antigens, Viral; D051792:Basic Helix-Loop-Helix Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D010100:Oxygen; D014157:Transcription Factors; D000099162:Endothelial PAS Domain-Containing Protein 1; C497443:Hif1a protein, mouse