Transcriptional regulation of human cardiac homeobox gene CSX1.
Cardiac homeobox gene Csx/Nkx-2.5 is essential for normal heart development and morphogenesis and is the earliest marker for cardiogenesis. To elucidate the regulatory mechanisms of Csx/Nkx-2.5 expression, we have isolated and characterized the upstream regulatory region of human Csx/Nkx-2.5 (CSX1). Transfection of the reporter gene containing a 965-bp CSX1 5' flanking region indicated that this region confers cardiomyocyte-predominant expression of CSX1. Deletion and mutational analyses revealed two positive cis-regulatory elements in this region that are essential for CSX1 expression in cardiomyocytes. Electrophoretic mobility shift assay revealed that nuclear proteins prepared from cardiac myocytes bound to these elements in a sequence-specific manner. The identification of cis-regulatory sequences of the Csx/Nkx-2.5 gene will facilitate further analysis for the upstream regulatory factors that control the expression of Csx/Nkx-2.5 and the process of vertebrate heart development.
Shiojima
I
I
Department of Cardiovascular Medicine, University of Tokyo Graduate School of Medicine, Japan.
Oka
T
T
Hiroi
Y
Y
Nagai
R
R
Yazaki
Y
Y
Komuro
I
I
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D019556:COS Cells; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics*; D005801:Genes, Homeobox / Q000235:genetics*; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D009928:Organ Specificity; D011401:Promoter Regions, Genetic / Q000235:genetics*; D020218:Response Elements / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics*; D014162:Transfection
D004268:DNA-Binding Proteins; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; C095552:NKX2-5 protein, human; D009687:Nuclear Proteins; D014157:Transcription Factors; D004247:DNA