Cooperative activation of atrial naturetic peptide promoter by dHAND and MEF2C.
An intricate array of cell-specific multiprotein complexes participate in programs of cell-specific gene expression through combinatorial interaction with different transcription factors and cofactors. The dHAND basic helix-loop-helix (bHLH) transcription factor, which is essential for heart development and extra embryonic structures, is thought to regulate cardiomyocyte-specific gene expression through combinatorial interactions with other cardiac-restricted transcription factors such as GATA4 and NKX2.5. Here, we determine that dHAND also interacts with the myocyte enhancer binding factor-2c (MEF2C) protein, which belongs to MADS-box transcription factors and is essential for heart development. dHAND and MEF2C synergistically activated expression of the atrial naturetic peptide gene (ANP) in transfected HeLa cells. GST-pulldown and immunoprecipitation assay demonstrate that full-length MEF2C protein is able to interact with dHAND in vitro and in vivo, just like MEF2A and bHLH transcription factors MyoD in skeletal muscle cells. In addition, electrophoretic mobility shift assays (EMSAs) demonstrate that MEF2C and dHAND do not influence each other's DNA binding activity. Using chromatin immunoprecipitation (ChIP) analysis in H9c2 cells we show that dHAND interact with MEF2C to form protein complex and bind A/T sequence in promoter of ANP. Taken together with previous observations, these results suggest the existence of large multiprotein transcriptional complex with core DNA binding proteins that physically interact with other transcriptional factors to form favorable conformation to potentiate transcription.
Zang
Ming-Xi
MX
Department of Nutrition & Food Hygiene, School of Public Health, Laboratory of Development Molecular Biology, Peking University Health Science Center, Beijing, China.
Li
Yong
Y
Xue
Li-Xiang
LX
Jia
Hong-Ti
HT
Jing
Hua
H
D009320:Atrial Natriuretic Factor / Q000235:genetics* / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins; D047369:Chromatin Immunoprecipitation; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation; D005982:Glutathione Transferase / Q000378:metabolism; D006367:HeLa Cells; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D026161:MADS Domain Proteins; D064326:MEF2 Transcription Factors; D018482:Muscle, Skeletal; D017570:MyoD Protein; D018006:Myogenic Regulatory Factors / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D029961:Zebrafish Proteins; D016335:Zinc Fingers
D009320:Atrial Natriuretic Factor; D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA; D004268:DNA-Binding Proteins; D005982:Glutathione Transferase; D026161:MADS Domain Proteins; D064326:MEF2 Transcription Factors; D017570:MyoD Protein; D018006:Myogenic Regulatory Factors; D014157:Transcription Factors; D029961:Zebrafish Proteins; C498765:HAND2 protein, human; C578040:MEF2C protein, human; C410915:hand2 protein, zebrafish