Wild-type human p53 transactivates the human proliferating cell nuclear antigen promoter.
The wild-type p53 protein is a transcriptional activator implicated in the control of cellular growth-related gene expression. Here, using a number of different cell lines and transient-transfection-transcription assays, we demonstrate that at low levels, wild-type p53 transactivates the human proliferating cell nuclear antigen (PCNA) promoter. When expressed at a similar level, the tumor-derived p53 mutants did not transactivate the PCNA promoter. We identified a p53-binding site on the human PCNA promoter with which p53 interacts sequence specifically. When placed on a heterologous synthetic promoter, the binding site functions as a wild-type p53 response element in either orientation. Deletion of the p53-binding site renders the PCNA promoter p53 nonresponsive, showing that wild-type p53 transactivates the PCNA promoter by binding to the site. At a higher concentration, wild-type p53 inhibits the PCNA promoter but p53 mutants activate. Transactivation by p53 mutants does not require the p53-binding site. These observations suggest that moderate elevation of the cellular wild-type p53 level induces PCNA production to help in DNA repair.
Department of Microbiology, University of Texas Health Science Center at San Antonio 78284, USA.
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Shivakumar
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Brown
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D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002522:Chlorocebus aethiops; D003850:Deoxyribonuclease I; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis* / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D013379:Substrate Specificity; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000378:metabolism*; D014709:Vero Cells
D009838:Oligodeoxyribonucleotides; D018809:Proliferating Cell Nuclear Antigen; D011994:Recombinant Proteins; D016159:Tumor Suppressor Protein p53; D003850:Deoxyribonuclease I