Activity of human papillomavirus type 16 P97 promoter in immortal and tumorigenic human oral keratinocytes.
We previously immortalized normal human oral keratinocytes (NHOK) by transfection with cloned human papillomavirus type 16 (HPV-16) genome and converted these immortalized cells to tumorigenic cells with chemical carcinogens. Since the tumorigenic cells expressed higher level of HPV-16 E6/E7 transcripts, we predicted that enhanced E6/E7 expression was induced by mutations at the long control region (LCR) of the viral genome integrated into cellular chromosome. To test this possibility, we sequenced the entire HPV-16 LCR from immortalized and tumorigenic cells, but no difference in the sequences in all of the tested cells was observed. However, it is possible that such differences in the expression of E6/E7 could have originated from different activities of cellular transcription factors in the different cells. To examine this prospect, we subcloned entire LCR into a reporter gene and determined the promoter activity of LCR in immortalized and tumorigenic cells. We found that the LCR promoter activity was significantly higher in tumorigenic cells when comparing to immortalized cells. We also observed that at least 477 nucleotides upstream of E6 open reading frame are needed for the maximum LCR promoter activity in tumorigenic cells.
Kook
J K
JK
Department of Oral Biochemistry and Dental Research Institute, College of Dentistry, Seoul National University, Seoul 110-749, Korea.
Kim
J H
JH
Min
B M
BM
D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D022762:CCAAT-Enhancer-Binding Proteins; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004742:Enhancer Elements, Genetic / Q000235:genetics; D015870:Gene Expression; D005786:Gene Expression Regulation; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D009061:Mouth Mucosa / Q000166:cytology*; D009154:Mutation; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D009856:Oncogene Proteins, Viral / Q000235:genetics; D027383:Papillomaviridae / Q000235:genetics*; D050725:Papillomavirus E7 Proteins; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D012097:Repressor Proteins; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1
D022762:CCAAT-Enhancer-Binding Proteins; D004279:DNA, Viral; D004268:DNA-Binding Proteins; C068651:E6 protein, Human papillomavirus type 16; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; C059731:oncogene protein E7, Human papillomavirus type 16; D015500:Chloramphenicol O-Acetyltransferase