title: Induction of p53-dependent activation of the human proliferating cell nuclear antigen gene in chromatin by ionizing radiation.
abstract: A human fibroblast cell line with conditional p53 expression displayed a p53-dependent increase in both the protein and mRNA levels of proliferating cell nuclear antigen (PCNA) after exposure to ionizing radiation (IR). The combination of p53 induction and IR cooperated to activate a transiently expressed human PCNA promoter-reporter gene via a p53-responsive element. Chromatin immunoprecipitation assays with antibodies specific for p53 or p300/CREB-binding protein revealed specific p53-dependent enrichment of PCNA promoter sequences in immunoprecipitates of sheared chromatin prepared from irradiated cells. Maximal and specific association of acetylated histone H4 with the PCNA promoter also depended on p53 induction and exposure to IR. These data demonstrate p53 binding to a target site in the PCNA promoter, recruitment of p300/CREB-binding protein, and localized acetylation of histone H4 in an IR-dependent manner. These molecular events are likely to play a role in mediating activation of PCNA gene expression by p53 during the cellular response to DNA damage. The analyses indicate that the combination of p53 induction and IR activate the PCNA gene via mechanisms similar to that of p21/wild-type p53-activated factor but to a lesser extent. This differential regulation of PCNA and p21/wild-type p53-activated factor may establish the proper ratio of the two proteins to coordinate DNA repair with cell cycle arrest.
authors.affiliation: Programs in Molecular and Cellular Biology and Lung Biology, Department of Pathology, Tulane Cancer Center and Tulane/Xavier Center for Bioenvironmental Research, New Orleans, Louisiana 70112, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Shan
authors.forename: Jin
authors.initials: J
authors.lastname: Xu
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhuo
authors.forename: Cindy A
authors.initials: CA
authors.lastname: Morris
authors.forename: Gilbert F
authors.initials: GF
authors.lastname: Morris
mesh_terms: D000107:Acetylation; D000123:Acetyltransferases / Q000378:metabolism; D015152:Blotting, Northern; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D002843:Chromatin / Q000737:chemistry*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000032:analysis / Q000235:genetics; D004247:DNA / Q000378:metabolism; D004260:DNA Repair; D005347:Fibroblasts; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000528:radiation effects*; D051548:Histone Acetyltransferases; D006657:Histones / Q000378:metabolism; D006801:Humans; D007163:Immunosorbent Techniques; D016133:Polymerase Chain Reaction; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D020218:Response Elements / Q000235:genetics; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53 / Q000032:analysis / Q000494:pharmacology*; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor
chemical_list: D000123:Acetyltransferases; D018797:Cell Cycle Proteins; D002843:Chromatin; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004247:DNA; D051548:Histone Acetyltransferases; D006657:Histones; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; C493956:CDKN1A protein, human