title: Kinetics of repression by modified p53 on the PDGF beta-receptor promoter.
abstract: Herein, we show that both exogenously transfected and endogenously activated p53 repress promoter activity and expression of PDGFRB. p53 binds the proximal promoter containing the CCAAT motif as examined by EMSA and chromatin immunoprecipitation. However, gradual induction of p53 in tet-onSAOS2 cells resulted in a transient increase of the PDGFRB-promoter activity and its expression. As binding of p53 to the promoter increased, previously bound p73, DeltaNp73, c-Myc, HDAC1 and HDAC4 were dismissed from the repressed promoter, and p300 was recruited. The transient increase of the promoter activity was therefore induced by the release of the p73, Myc and HDACs, previously shown to act as repressors to this promoter. Along with further increase of p53, p300 was replaced by HDAC1 and HDAC4, resulting in decreased PDGFRB expression. For the repression, acetylation of the C-terminal lysines of p53 is important, and both acetyl-K373p53 and methyl-K370p53 became bound to the promoter. The acetyl-K373p53 was accumulated in the nucleus and colocalized with promyelocytic leukemia protein. Mitomycin treatment of MEF induced similar epigenetic modification of p53 and its binding to the promoter chromatin. Addition of a PDGFR tyrosine-kinase inhibitor to p53-inducing tet-onSAOS2 increased the number of apoptotic cells. These results suggest that p53 represses the PDGFRB promoter, facilitating the p53-induced apoptosis, whereas tumor cells with p53 mutation or a high level of DeltaNp73 or Myc could become refractory to the regulation.
authors.affiliation: Department of Medical Chemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Weiwen
authors.initials: W
authors.lastname: Yang
authors.forename: Daniel
authors.initials: D
authors.lastname: Wetterskog
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Keiko
authors.initials: K
authors.lastname: Funa
mesh_terms: D017209:Apoptosis; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D004268:DNA-Binding Proteins / Q000502:physiology; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases / Q000502:physiology; D006801:Humans; D007700:Kinetics; D008745:Methylation; D016685:Mitomycin / Q000494:pharmacology; D009687:Nuclear Proteins / Q000502:physiology; D011401:Promoter Regions, Genetic; D016271:Proto-Oncogene Proteins c-myc / Q000502:physiology; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000235:genetics*; D012097:Repressor Proteins / Q000502:physiology; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*; D025521:Tumor Suppressor Proteins / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; C489427:MYC protein, human; D009687:Nuclear Proteins; D016271:Proto-Oncogene Proteins c-myc; D012097:Repressor Proteins; C000606460:TP73 protein, human; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C000606369:delta Np73 protein, human; D016685:Mitomycin; D020797:Receptor, Platelet-Derived Growth Factor beta; C110550:HDAC1 protein, human; C400300:HDAC4 protein, human; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases