title: p73 or p53 directly regulates human p53 transcription to maintain cell cycle checkpoints.
abstract: Whereas the p53 tumor suppressor protein plays a central role in cellular checkpoints that respond to damage or stress to prevent tumorigenesis, the transcriptional control of the p53 gene has remained unclear. We show that chemotherapeutic agents induce p53 transcription and that p73 or p53 transactivates endogenous p53 expression through direct binding to the p53 promoter. Silencing of p53 or p73 by RNA interference significantly suppresses p53 transcription under physiologic conditions or in response to cellular stress. Mutational analysis of the human p53 promoter localized a p53 DNA-binding site, which confers p53- or p73-dependent p53 promoter activation. Importantly, impaired p53-mediated autoregulation of p53 transcription by inducible-interfering RNA results in aberrant cell cycle regulation and suppression of p53-mediated apoptosis. Thus, a positive feedback loop regulates human p53 expression and involves p73 and p53. Disruption of p53 transcription contributes to defective checkpoint control.
authors.affiliation: Laboratory of Molecular Oncology and Cell Cycle Regulation, Department of Medicine (Hematology/Oncology), University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
authors.forename: Shulin
authors.initials: S
authors.lastname: Wang
authors.forename: Wafik S
authors.initials: WS
authors.lastname: El-Deiry
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D002453:Cell Cycle / Q000235:genetics*; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D020868:Gene Silencing; D016147:Genes, Tumor Suppressor; D016158:Genes, p53; D045325:HCT116 Cells; D006801:Humans; D009154:Mutation; D009369:Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000187:drug effects; D015533:Transcriptional Activation / Q000187:drug effects; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D025521:Tumor Suppressor Proteins
chemical_list: D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C495901:TP53 protein, human; C000606460:TP73 protein, human; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins