Characterization of Kaposi's sarcoma-associated herpesvirus (KSHV) K1 promoter activation by Rta.
The K1 gene of Kaposi's sarcoma-associated herpesvirus (KSHV) encodes a 46-kDa transmembrane glycoprotein that possesses transforming properties, initiates signaling pathways in B cells, and prevents apoptosis. Here, we demonstrate a mechanism for activation of the K1 promoter by the Rta transactivator. Electrophoretic mobility shift assay (EMSA) analysis of the K1 promoter demonstrated that purified Rta protein bound to the K1 promoter at three locations, independent of other DNA-binding factors. Transcriptional assays revealed that only two of these Rta DNA-binding sites are functionally significant, and that they could impart Rta responsiveness to a heterologous E4 TATA box promoter. In addition, TATA-binding protein (TBP) bound to a TATA box element located 25 bp upstream of the K1 transcription start site and was also shown to associate with Rta by coimmunoprecipitation analysis. Rta transactivation may therefore be mediated in part through recruitment of TBP to target promoters.
Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, 27599, USA.
Brian S
BS
Bowser
Stephanie
S
Morris
Moon Jung
MJ
Song
Ren
R
Sun
Blossom
B
Damania
D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D001667:Binding, Competitive; D002460:Cell Line; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D005814:Genes, Viral; D019288:Herpesvirus 8, Human / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D020218:Response Elements; D016385:TATA Box; D035181:TATA-Box Binding Protein / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation; D014162:Transfection; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
D004279:DNA, Viral; D017874:Immediate-Early Proteins; C111600:K1 protein, Human herpesvirus 8; C417604:Rta protein, Human herpesvirus 8; D035181:TATA-Box Binding Protein; D015534:Trans-Activators; D014764:Viral Proteins