title: Functional interaction between DP-1 and p53.
abstract: The cellular transcription factor DRTF1/E2F and the tumor suppressor protein p53 play important roles in controlling early cell cycle events. DRTF1/E2F is believed to coordinate and integrate the transcription of cell cycle-regulating genes, for example, those involved in DNA synthesis, with the activity of regulatory proteins, such as the retinoblastoma tumor suppressor gene product (pRb), which modulate its transcriptional activity. In contrast, p53 is thought to monitor the integrity of chromosomal DNA and when appropriate interfere with cell cycle progression, for example, in response to DNA damage. Generic DRTF1/E2F DNA binding activity and transcriptional activation arise when members of two distinct families of proteins, such as DP-1 and E2F-1, interact as DP/E2F heterodimers. In many cell types, DP-1 is a widespread component of DRTF1/E2F DNA binding activity which when expressed at high levels oncogenically transforms embryonic fibroblasts. Here, we document an association between DP-1 and p53 and demonstrate its presence in mammalian cell extracts. In vitro p53 interacts with an immunochemically distinct form of DP-1 and in vivo can regulate transcription driven by the DP-1/E2F-1 heterodimer. At the biochemical level, p53 competes with E2F-1 for DP-1, with a consequent reduction in DNA binding activity. Mutational analysis defines within DP-1 a C-terminal region required for the interaction with p53 and within p53 an N-terminal region distinct from that required to bind to MDM2. Our results establish DRTF1/E2F as a common cellular target in growth control mediated through the activities of pRb and p53 and suggest an alternative mechanism through which p53 may regulate cellular proliferation.
authors.affiliation: Laboratory of Eukaryotic Molecular Genetics, MRC National Institute for Medical Research, London, United Kingdom.
authors.forename: T S
authors.initials: TS
authors.lastname: Sørensen
authors.forename: R
authors.initials: R
authors.lastname: Girling
authors.forename: C W
authors.initials: CW
authors.lastname: Lee
authors.forename: J
authors.initials: J
authors.lastname: Gannon
authors.forename: L R
authors.initials: LR
authors.lastname: Bandara
authors.forename: N B
authors.initials: NB
authors.lastname: La Thangue
mesh_terms: D000818:Animals; D001665:Binding Sites; D018236:Carcinoma, Embryonal; D002352:Carrier Proteins; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002460:Cell Line; D002474:Cell-Free System; D002846:Chromatography, Affinity; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D017930:Genes, Reporter; D006801:Humans; D008156:Luciferases / Q000096:biosynthesis; D051379:Mice; D016297:Mutagenesis, Site-Directed; D011994:Recombinant Proteins / Q000378:metabolism; D056465:Retinoblastoma-Binding Protein 1; D016324:Sequence Tagged Sites; D013762:Tetrahydrofolate Dehydrogenase / Q000096:biosynthesis; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: C533431:Arid4a protein, mouse; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; C493754:E2f1 protein, mouse; D011994:Recombinant Proteins; D056465:Retinoblastoma-Binding Protein 1; C493735:TFDP1 protein, human; C493736:Tfdp1 protein, mouse; D050680:Transcription Factor DP1; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D008156:Luciferases; D013762:Tetrahydrofolate Dehydrogenase