Down regulation of the interleukin-8 promoter by human papillomavirus type 16 E6 and E7 through effects on CREB binding protein/p300 and P/CAF.
Previously, we reported that human papillomavirus (HPV) type 16 E6 binds to C/H1, C/H3, and the C-terminal domains of coactivators p300 and CBP, causing the modulation of the transcription of certain genes controlled by NF-kappaB (p65 or relA) and p53. To establish the biological significance of these observations, we have focused on the transcriptional regulation of interleukin-8 (IL-8), a potent chemoattractant for T lymphocytes and neutrophils, which is also essential for the initiation of the local immune response. The IL-8 promoter is regulated by NF-kappaB/p65 in response to tumor necrosis factor alpha and requires the cooperation of the coactivators CBP/p300 and steroid receptor coactivator 1 (SRC-1) and the p300/CBP-associated factor (P/CAF) for optimal activation. Here we report that, in the presence of HPV-16 E6, the promoter activity of IL-8 was repressed. Moreover, from the mutational analysis of the IL-8 promoter, we found that E6 down-regulates the IL-8 promoter activity through the NF-kappaB/p65 binding site. This inhibition appears to result from the ability of HPV-16 E6 to compete with NF-kappaB/p65 and SRC-1 for binding to the N terminus and C terminus of CBP, respectively. Reporter data also showed that E7 represses IL-8 promoter activity, though to a lesser extent than E6 but, like E6, the repression by E7 is through the NF-kappaB/p65 binding site. E7 was shown for the first time to bind to P/CAF, and the binding was necessary for the down regulation of the IL-8 promoter. E6 and E7 together inhibited transcription of the IL-8 promoter to a greater extent than either alone. Finally, by RNase protection assay, we showed that the synthesis of endogenous IL-8 mRNA was repressed in keratinocytes stably expressing E6 and E7. Taken together, the results provide evidence that E6 and E7 can cooperatively disrupt IL-8 transcription through disruption of transcriptional active complexes, and this may have important consequences for immune responses in infected hosts.
Huang
Shih-Min
SM
Department of Microbiology and Immunology. The Cancer Center, University of Rochester, Rochester, New York 14642, USA.
McCance
D J
DJ
D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D001667:Binding, Competitive; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D015536:Down-Regulation; D051548:Histone Acetyltransferases; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism*; D015603:Keratinocytes; D009154:Mutation; D016328:NF-kappa B / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D056920:Nuclear Receptor Coactivator 1; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism*; D050725:Papillomavirus E7 Proteins; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012097:Repressor Proteins; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor
D000123:Acetyltransferases; D018797:Cell Cycle Proteins; D051548:Histone Acetyltransferases; D016209:Interleukin-8; D016328:NF-kappa B; D009687:Nuclear Proteins; D056920:Nuclear Receptor Coactivator 1; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; C068651:E6 protein, Human papillomavirus type 16; C059731:oncogene protein E7, Human papillomavirus type 16; C538859:NCOA1 protein, human