Low p53 level in immortal, non-tumorigenic oral keratinocytes harboring HPV-16 DNA.
The p53 protein level was determined in normal oral keratinocytes and two non-tumorigenic, immortal oral keratinocyte lines harboring human papillomavirus-16 (HPV-16)DNA. The p53 mRNA level in the immortal cells was higher than the normal counterpart, but the p53 protein level was notably lower in the immortalised cells. The half-life of p53 protein in the normal and immortal cells was < 1 h, and the p53 cDNA sequence of these cells showed no mutation. The immortal cells transcribed a high amount of E6/E7 mRNA encoded by HPV-16, but normal cells did not. These observations suggest that the immortal keratinocytes may translate normal level of wild-type p53 protein, and the low p53 level in these cells may be due to the enhanced degradation of the protein by HPV-16 E6 protein.
Li
S L
SL
UCLA School of Dentistry, Los Angeles, California 90024.
Kim
M S
MS
Cherrick
H M
HM
Park
N H
NH
D015152:Blotting, Northern; D002461:Cell Line, Transformed; D004279:DNA, Viral / Q000302:isolation & purification*; D016158:Genes, p53; D006801:Humans; D015603:Keratinocytes / Q000737:chemistry*; D009061:Mouth Mucosa / Q000166:cytology; D009856:Oncogene Proteins, Viral; D027383:Papillomaviridae / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D012097:Repressor Proteins; D016159:Tumor Suppressor Protein p53 / Q000032:analysis*
D004279:DNA, Viral; C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D012333:RNA, Messenger; D012097:Repressor Proteins; D016159:Tumor Suppressor Protein p53