Cooperative interaction between the basic helix-loop-helix transcription factor dHAND and myocyte enhancer factor 2C regulates myocardial gene expression.
Cardiac-restricted transcription factors dHAND and myocyte enhancer factor 2C are expressed in the developing heart and activate several cardiac promoters. However, their regulatory mechanisms are still to be understood. To elucidate their exact regulatory functions, we have developed an RNA interference strategy to specifically inhibit dHAND and myocyte enhancer factor 2C protein production in H9c2 cells, which are derived from rat embryonic heart. Expression of endogenous cardiac genes atrial natriuretic peptide and alpha-myosin heavy chain was down-regulated in H9c2 cells lacking both dHAND and myocyte enhancer factor 2C, indicating that these factors are required for the maintenance of the cardiac genetic program. Consistent with these, expression of atrial natriuretic peptide and alpha-myosin heavy chain was up-regulated in H9c2 cells, which overexpressed dHAND and myocyte enhancer factor 2C. In addition, dHAND and myocyte enhancer factor 2C interact to synergistically activate atrial natriuretic peptide and alpha-myosin heavy chain transcription. Furthermore, chromatin immunoprecipitation analysis in H9c2 cells treated with phenylephrine showed that dHAND and myocyte enhancer factor 2C protein complex bind to the A/T sequence on atrial natriuretic peptide promoter. Taken together, these results not only suggest that the complex cis-trans interaction of dHAND, myocyte enhancer factor 2C, and the target gene may fine-tune gene expression in cardiac myocytes but also provide a molecular paradigm to elucidate the mechanisms of action of dHAND and myocyte enhancer factor 2C in the developing heart.
Laboratory of Development Molecular Biology, Department of Nutrition and Food Hygiene, School of Public Health, Peking University Health Science Center, Beijing 100083, China.
Ming-Xi
MX
Zang
Yong
Y
Li
Hao
H
Wang
Jun-Bo
JB
Wang
Hong-Ti
HT
Jia
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000235:genetics; D051792:Basic Helix-Loop-Helix Proteins; D001665:Binding Sites; D002460:Cell Line; D002843:Chromatin / Q000737:chemistry; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D004347:Drug Interactions; D004357:Drug Synergism; D004622:Embryo, Mammalian; D015870:Gene Expression; D005786:Gene Expression Regulation; D007163:Immunosorbent Techniques; D064326:MEF2 Transcription Factors; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism*; D018006:Myogenic Regulatory Factors / Q000235:genetics / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000235:genetics; D010656:Phenylephrine / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D024723:Ventricular Myosins / Q000235:genetics; D029961:Zebrafish Proteins
D009320:Atrial Natriuretic Factor; D051792:Basic Helix-Loop-Helix Proteins; D002843:Chromatin; D004247:DNA; D004268:DNA-Binding Proteins; D064326:MEF2 Transcription Factors; D018006:Myogenic Regulatory Factors; D018995:Myosin Heavy Chains; D010656:Phenylephrine; D034741:RNA, Small Interfering; D014157:Transcription Factors; D024723:Ventricular Myosins; D029961:Zebrafish Proteins; C498767:Hand2 protein, rat; C410915:hand2 protein, zebrafish