title: p73 Interacts with c-Myc to regulate Y-box-binding protein-1 expression.
abstract: YB-1 is a member of the cold shock domain family of proteins that is important for signaling DNA damage and cell proliferation. YB-1 is induced by DNA damage and can also recognize cisplatin-modified DNA. In this study we observed a 6-fold increase in the steady-state level of YB-1 mRNA in response to cisplatin exposure in cells of the human cancer cell line KB. We present evidence from cotransfection experiments for a critical role of c-Myc and p73 in the transactivation of the YB-1 promoter. p73 transactivated the YB-1 promoter in experiments with Saos-2 cells, which express c-Myc, but not with HO15.19 cells, which lack c-Myc. In turn, c-Myc transactivated an intact YB-1 promoter but not a YB-1 promoter with a mutant E-box, indicating that the E-box is necessary for the response of the promoter to cisplatin. We also found that p73 interacts with c-Myc in vitro and in vivo. Using deletion mutants we showed that the DNA-binding domain of p73 and the C-terminal region of c-Myc are required for the interaction. Furthermore, p73 stimulated the interaction of Max with c-Myc and promoted binding of the c-Myc-Max complex to its target DNA. Our data suggest that p73 stimulates the transcription of the YB-1 promoter by enhancing recruitment of the c-Myc-Max complex to the E-box.
authors.affiliation: Department of Molecular Biology, University of Occupational and Environmental Health, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Uramoto
authors.forename: Hiroto
authors.initials: H
authors.lastname: Izumi
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ise
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Tada
authors.forename: Takeshi
authors.initials: T
authors.lastname: Uchiumi
authors.forename: Michihiko
authors.initials: M
authors.lastname: Kuwano
authors.forename: Kosei
authors.initials: K
authors.lastname: Yasumoto
authors.forename: Keiko
authors.initials: K
authors.lastname: Funa
authors.forename: Kimitoshi
authors.initials: K
authors.lastname: Kohno
mesh_terms: D000818:Animals; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D050976:Basic-Leucine Zipper Transcription Factors; D001665:Binding Sites; D001859:Bone Neoplasms; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics*; D019556:COS Cells; D002522:Chlorocebus aethiops; D002945:Cisplatin / Q000494:pharmacology; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts; D005786:Gene Expression Regulation; D016147:Genes, Tumor Suppressor; D006801:Humans; D007624:KB Cells; D051839:NFI Transcription Factors; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012516:Osteosarcoma; D011401:Promoter Regions, Genetic; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D017384:Sequence Deletion; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; D051840:Y-Box-Binding Protein 1
chemical_list: D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D050976:Basic-Leucine Zipper Transcription Factors; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; C499330:MAX protein, human; C499329:Max protein, rat; C067850:Myc associated factor X; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D011994:Recombinant Proteins; C000606460:TP73 protein, human; D014157:Transcription Factors; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; D002945:Cisplatin