Transcriptional activation by the human herpesvirus-8-encoded interferon regulatory factor.
Human herpesvirus-8 (HHV-8), a gammaherpesvirus that is thought to be the viral aetiologic agent of Kaposi's sarcoma and primary effusion lymphoma, encodes a homologue to cellular interferon regulatory factors (IRFs). The HHV-8 IRF homologue (vIRF; ORF K9) has previously been shown to inhibit gene induction by interferons and IRF-1 and to transform NIH3T3 cells or Rat-1 cells. Additionally, expression of antisense to vIRF in BCBL-1 cells results in the repression of certain HHV-8 genes, suggesting that vIRF may also positively regulate gene expression. We demonstrate that vIRF activates transcription when directed to DNA by the GAL4 DNA-binding domain. GAL-vIRF truncation constructs that individually are incapable of activating transcription can cooperate in transactivation when coexpressed in HeLa cells, suggesting that multiple regions of vIRF are involved in transactivation. These studies broaden the potential mechanisms of action of vIRF to include transcriptional activation as well as transcriptional repression.
Roan
Florence
F
Program in Biochemistry, Cell and Developmental Biology2 and Department of Medicine4, Emory University, Atlanta, GA 30322, USA.|Winship Cancer Center, Emory University, 1365-B Clifton Road NE, Atlanta, GA 30322, USA1.
Zimring
James C
JC
Winship Cancer Center, Emory University, 1365-B Clifton Road NE, Atlanta, GA 30322, USA1.
Goodbourn
Stephen
S
Division of Biochemistry, Department of Cellular and Molecular Sciences, St George's Hospital Medical School, University of London, London SW17 0RE, UK3.
Offermann
Margaret K
MK
Program in Biochemistry, Cell and Developmental Biology2 and Department of Medicine4, Emory University, Atlanta, GA 30322, USA.|Winship Cancer Center, Emory University, 1365-B Clifton Road NE, Atlanta, GA 30322, USA1.
D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D006367:HeLa Cells; D019288:Herpesvirus 8, Human / Q000235:genetics; D006801:Humans; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014764:Viral Proteins; D015500:Chloramphenicol O-Acetyltransferase