title: p300 Functions as a coactivator of transcription factor GATA-4.
abstract: Transcription factor GATA-4 plays critical roles in controlling heart development and cardiac hypertrophy. To understand how GATA-4 functions under diverse conditions, we sought to identify its coactivators. We tested p300 as a coactivator in GATA-4-dependent transient transcription assays in NIH3T3 cells and found that p300 synergistically activated GATA-4-dependent transcription on both synthetic and natural promoters. Direct physical interactions between the N- and C-zinc finger domains of GATA-4 and the cysteine/histidine-rich region 3 (C/H3) of p300 were identified in immunoprecipitation and glutathione S-transferase pull-down experiments. Deletion of the C/H3 region of p300 abolished its coactivator activity indicating that the physical interaction was required for functional synergy. Through the use of a series of GATA-4 zinc finger mutants, the amino acids WRR in the C finger were identified as critical to the interaction. The adenoviral E1A protein or a peptide encoding the C/H3 region of p300 could inhibit GATA-4-dependent transcription, presumably by competing for p300 binding. Furthermore, deletion of the region of p300 encoding the histone acetyltransferase activity abolished its effect on GATA-4-dependent transcriptional activity. These results establish that p300 acts as a GATA-4 coactivator and that the p300 histone acetyltransferase activity is necessary for the functional interaction.
authors.affiliation: Department of Molecular Sciences, Pfizer Global Research and Development, Ann Arbor, Michigan 48105, USA.
authors.forename: Y S
authors.initials: YS
authors.lastname: Dai
authors.forename: B E
authors.initials: BE
authors.lastname: Markham
mesh_terms: D016475:3T3 Cells; D017500:Adenovirus E1A Proteins / Q000494:pharmacology; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000235:genetics; D019556:COS Cells; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D050881:E1A-Associated p300 Protein; D050991:GATA4 Transcription Factor; D017930:Genes, Reporter; D051379:Mice; D018995:Myosin Heavy Chains / Q000235:genetics; D009687:Nuclear Proteins / Q000378:metabolism / Q000502:physiology*; D017434:Protein Structure, Tertiary; D015534:Trans-Activators / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic / Q000502:physiology*; D016335:Zinc Fingers / Q000502:physiology
chemical_list: D017500:Adenovirus E1A Proteins; D004268:DNA-Binding Proteins; D050991:GATA4 Transcription Factor; D009687:Nuclear Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D009320:Atrial Natriuretic Factor; D050881:E1A-Associated p300 Protein; C494361:Ep300 protein, mouse; D018995:Myosin Heavy Chains