Induction of Id2 expression by cardiac transcription factors GATA4 and Nkx2.5.
Inhibitor of differentiation/DNA binding (Id) proteins function as a regulator of helix-loop-helix proteins participating in cell lineage commitment and differentiation. Here, we observed a marked induction of Id2 during cardiomyocyte differentiation from P19CL6 murine embryonic teratocarcinoma stem cells, prompting us to investigate the upstream regulatory mechanism of Id2 induction. Computer analysis of Id2 promoter and subsequent electrophoretic mobility shift assay revealed several binding sites for GATA4 and Nkx2.5 within the Id2 promoter. By further deletion and mutation analysis of the respective binding site, we identified that two motifs located at -497/-502 and -264/-270 were functionally important for Id2 promoter activation by GATA4 and Nkx2.5, respectively. Overexpression of GATA4 and/or Nkx2.5 induced not only Id2 promoter activity but also Id2 protein expression. Additionally, Id proteins significantly inhibit the GATA4 and Nkx2.5-dependent transcription, suggesting Id proteins may play a regulatory role in cardiogenesis. Collectively, our results demonstrate that GATA4 and Nkx2.5 could be one of the upstream regulators of Id2.
Lim
Joong-Yeon
JY
Division of Intractable Diseases, Center for Biomedical Sciences, National Institute of Health, 194, Tongillo, Eunpyeong-gu, Seoul 122-701, Korea.
Kim
Won Ho
WH
Kim
Joon
J
Park
Sang Ick
SI
D000818:Animals; D001665:Binding Sites; D002454:Cell Differentiation; D002460:Cell Line; D050991:GATA4 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D051797:Inhibitor of Differentiation Protein 2 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009206:Myocardium / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics
D050991:GATA4 Transcription Factor; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; C497452:Idb2 protein, mouse; D051797:Inhibitor of Differentiation Protein 2; C484469:Nkx2-5 protein, mouse; D014157:Transcription Factors