title: Auto-activation of the rta gene of human herpesvirus-8/Kaposi's sarcoma-associated herpesvirus.
abstract: Rta, mainly encoded by open reading frame 50 (ORF50), is the product of an immediate-early gene of human herpesvirus-8 (HHV-8)/Kaposi's sarcoma-associated herpesvirus. Rta is a transcriptional activator that is both necessary and sufficient to disrupt viral latency and activate the expression of downstream viral lytic genes. We report that ectopically expressed Rta protein could also activate the rta promoter on a reporter plasmid up to 144-fold, both in latently infected B cells and in uninfected epithelial cells, and that this activation was dose-dependent. Furthermore, by analysing the 5' untranslated region using ribonuclease protection assays, we demonstrated that transfection of an Rta expression plasmid into latently infected cells activated the expression of rta transcripts from endogenous viral genomes. We propose that auto-activation of the immediate-early gene, rta, is an important strategy for HHV-8 to effectively respond to environmental stimuli and maximally activate the virus lytic cycle.
authors.affiliation: Department of Molecular & Medical Pharmacology, UCLA AIDS Institute, Jonsson Comprehensive Cancer Center, and the Molecular Biology Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA1.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Deng
authors.affiliation: Department of Molecular & Medical Pharmacology, UCLA AIDS Institute, Jonsson Comprehensive Cancer Center, and the Molecular Biology Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA1.
authors.forename: Arthur
authors.initials: A
authors.lastname: Young
authors.affiliation: Department of Molecular & Medical Pharmacology, UCLA AIDS Institute, Jonsson Comprehensive Cancer Center, and the Molecular Biology Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA1.
authors.forename: Ren
authors.initials: R
authors.lastname: Sun
mesh_terms: D020121:5' Untranslated Regions / Q000032:analysis / Q000235:genetics; D001402:B-Lymphocytes / Q000187:drug effects / Q000821:virology; D002087:Butyrates / Q000494:pharmacology; D002460:Cell Line; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D017781:Genes, Immediate-Early / Q000235:genetics*; D017930:Genes, Reporter / Q000235:genetics; D005814:Genes, Viral / Q000235:genetics*; D019288:Herpesvirus 8, Human / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics* / Q000378:metabolism*; D023282:Nuclease Protection Assays; D011401:Promoter Regions, Genetic / Q000235:genetics; D012367:RNA, Viral / Q000032:analysis / Q000235:genetics; D012260:Ribonucleases / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism*; D014162:Transfection; D014764:Viral Proteins; D017735:Virus Latency / Q000235:genetics
chemical_list: D020121:5' Untranslated Regions; D002087:Butyrates; D017874:Immediate-Early Proteins; D012367:RNA, Viral; C417604:Rta protein, Human herpesvirus 8; D015534:Trans-Activators; D014764:Viral Proteins; D012260:Ribonucleases; D013755:Tetradecanoylphorbol Acetate