The transcription factors GATA4 and dHAND physically interact to synergistically activate cardiac gene expression through a p300-dependent mechanism.
An intricate array of heterogeneous transcription factors participate in programming tissue-specific gene expression through combinatorial interactions that are unique to a given cell-type. The zinc finger-containing transcription factor GATA4, which is widely expressed in mesodermal and endodermal derived tissues, is thought to regulate cardiac myocyte-specific gene expression through combinatorial interactions with other semi-restricted transcription factors such as myocyte enhancer factor 2, nuclear factor of activated T-cells, serum response factor, and Nkx2.5. Here we determined that GATA4 also interacts with the cardiac-expressed basic helix-loop-helix transcription factor dHAND (also known as HAND2). GATA4 and dHAND synergistically activated expression of cardiac-specific promoters from the atrial natriuretic factor gene, the b-type natriuretic peptide gene, and the alpha-myosin heavy chain gene. Using artificial reporter constructs this functional synergy was shown to be GATA site-dependent, but E-box site-independent. A mechanism for the transcriptional synergy was suggested by the observation that the bHLH domain of dHAND physically interacted with the C-terminal zinc finger domain of GATA4 forming a higher order complex. This transcriptional synergy observed between GATA4 and dHAND was associated with p300 recruitment, but not with alterations in DNA binding activity of either factor. Moreover, the bHLH domain of dHAND directly interacted with the CH3 domain of p300 suggesting the existence of a higher order complex between GATA4, dHAND, and p300. Taken together with previous observations, these results suggest the existence of an enhanceosome complex comprised of p300 and multiple semi-restricted transcription factors that together specify tissue-specific gene expression in the heart.
Dai
Yan-Shan
YS
Department of Pediatrics, University of Cincinnati, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA.
Cserjesi
Peter
P
Markham
Bruce E
BE
Molkentin
Jeffery D
JD
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000235:genetics; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism*; D050881:E1A-Associated p300 Protein; D050991:GATA4 Transcription Factor; D005786:Gene Expression Regulation / Q000502:physiology*; D006162:Guanylate Cyclase; D006367:HeLa Cells; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D016296:Mutagenesis; D009206:Myocardium / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics*; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D051381:Rats; D017461:Receptors, Atrial Natriuretic Factor / Q000235:genetics; D017384:Sequence Deletion; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D029961:Zebrafish Proteins; D016335:Zinc Fingers; D000099242:Atrial Natriuretic Factor Receptor B
D009320:Atrial Natriuretic Factor; D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D050881:E1A-Associated p300 Protein; D050991:GATA4 Transcription Factor; D006162:Guanylate Cyclase; D018995:Myosin Heavy Chains; D009687:Nuclear Proteins; D017461:Receptors, Atrial Natriuretic Factor; D015534:Trans-Activators; D014157:Transcription Factors; D029961:Zebrafish Proteins; D000099242:Atrial Natriuretic Factor Receptor B; C498765:HAND2 protein, human; C498767:Hand2 protein, rat; C410915:hand2 protein, zebrafish; C494362:Ep300 protein, rat