title: The Zif268 cellular transcription factor activates expression of the Epstein-Barr virus immediate-early BRLF1 promoter.
abstract: The Epstein-Barr virus immediate-early protein BZLF1 mediates the switch from latent to lytic infection. BZLF1 transcription can be derived from either the BZLF1 promoter or the BRLF1 promoter (Rp). Productive viral infection of EBV-infected B cells can be induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment, as well as cross-linking of surface immunoglobulin with antiimmunoglobulin antibody. Both TPA and antiimmunoglobulin antibody are known to activate expression of the cellular transcription factor Zif268 in B cells. In this study, we have examined the regulation of BZLF1 transcription by Zif268. We show that Rp (but not the BZLF1 promoter) is activated by Zif268. Bacterially synthesized Zif268 binds strongly to an upstream sequence in the Rp promoter (located from -131 to -123 relative to the start site) and more weakly to a proximal sequence (-49 to -40). Zif268 activation of Rp requires these two Zif268 binding sites. TPA treatment of B cells induces the expression of Zif268 protein, which binds to Rp. Furthermore, TPA activation of Rp requires the upstream Zif268 site. These findings indicate that Zif268 can activate a critical Epstein-Barr virus immediate-early promoter and, therefore, may play a key role in the regulation of viral latency.
authors.affiliation: Department of Medicine, University of North Carolina, Chapel Hill, USA.
authors.forename: S
authors.initials: S
authors.lastname: Zalani
authors.forename: E
authors.initials: E
authors.lastname: Holley-Guthrie
authors.forename: S
authors.initials: S
authors.lastname: Kenney
mesh_terms: D001483:Base Sequence; D015342:DNA Probes; D004268:DNA-Binding Proteins / Q000378:metabolism*; D051766:Early Growth Response Protein 1; D015967:Gene Expression Regulation, Viral / Q000235:genetics; D017781:Genes, Immediate-Early; D006367:HeLa Cells; D004854:Herpesvirus 4, Human / Q000235:genetics*; D006801:Humans; D017874:Immediate-Early Proteins; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017384:Sequence Deletion; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014764:Viral Proteins; D017735:Virus Latency / Q000235:genetics; D016335:Zinc Fingers
chemical_list: C068382:BRLF1 protein, Human herpesvirus 4; D015342:DNA Probes; D004268:DNA-Binding Proteins; C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; D017874:Immediate-Early Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D014764:Viral Proteins; D013755:Tetradecanoylphorbol Acetate