[YY1 and its repressive effect on human papillomavirus 16 early promoter P97 existed widely among human epithelial cell lines].
Cellular transcription factor YY1 represses the activity of early promoter P97 of HPV 16. Removal of the specific binding sites for YY1 in HPV 16 LCR can increase the P97 activity. To analyse the expression of YY1 and the existence of the activation effect on P97 due to removing YY1 binding sites in the LCR region, we extracted nuclear proteins from four cervical cancer cell lines and two human keratinocytes. EMSA assays were carried out in vitro. At the same time, we transiently transfected the luciferase reporter plasmids, which contain HPV 16 reference and mutated LCR sequences, respectively, into the different cells and determined the luciferase expressions. The results showed that all the analysed cell lines contained biologically functional YY1 proteins. No remarkable difference in the concentration of native YY1 proteins could be detected among the tested cells. Removal of YY1 binding sites in HPV 16 LCR could elevate P97 activity in several analysed cell lines, including normal human primary kerationcytes from foreskin. It suggests that YY1 regulatory system exists widely in human epithelial cell lines. We also found that the transcription activator NF1 was more highly expressed in C33a cell than in HT3 cell, indicating an unevenly distribution of functional proteins in various cell lines.
Dong
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X
Institute of Virology, Chinese Academy of Preventive Medicine, Beijing 100052.
Liu
H
H
Pfister
H
H
D002478:Cells, Cultured; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D050981:Erythroid-Specific DNA-Binding Factors; D005260:Female; D006367:HeLa Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D027383:Papillomaviridae / Q000235:genetics*; D017354:Point Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics*; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D014407:Tumor Cells, Cultured; D050986:YY1 Transcription Factor
D050981:Erythroid-Specific DNA-Binding Factors; D014157:Transcription Factors; D050986:YY1 Transcription Factor; C494698:YY1 protein, human