Alpha(1)-adrenergic activation of the cardiac ankyrin repeat protein gene in cardiac myocytes.
Cardiac ankyrin repeat protein (CARP) is a nuclear transcription cofactor that is activated by multiple signaling pathways in hypertrophic cardiac myocytes. Since CARP has been reported to be a transcriptional co-repressor, its activation during hypertrophy might contribute to the deregulation of gene expression leading to heart failure. Here, we found that alpha(1)-adrenergic signaling activates CARP mRNA expression in rat cardiac myocytes. To examine how alpha(1)-adrenergic signaling activates the CARP gene, a 660 bp fragment of the mouse CARP promoter was cloned. Previous reports suggested that the mouse CARP promoter was dependent on the GATA4 transcription factor whereas the human CARP promoter was dependent on transcriptional enhancer factor-1 (TEF-1). TEF-1 and GATA4 transcription factors, known mediators of alpha(1)-adrenergic signaling, bound to the mouse CARP promoter at several sites as determined by gel mobility shift assays. These sites are highly conserved between the mouse and human promoters, suggesting that they are functionally important in both. Mutation analysis showed that binding of TEF-1 factors is required for basal activity of the CARP promoter in cardiac myocytes. However, over-expression of TEF-1 factors could not potentiate the response of the CARP promoter to alpha(1)-adrenergic stimulation. On the other hand, the alpha(1)-adrenergic response was potentiated by GATA4 over-expression. Taken together, our results demonstrate that alpha(1)-adrenergic signaling regulates CARP expression in cardiac myocytes, in part through the transcription factor GATA4.
Maeda
Tomoji
T
Cardiovascular Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA.
Sepulveda
Jorge
J
Chen
Hsiao-Huei
HH
Stewart
Alexandre F R
AF
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D050991:GATA4 Transcription Factor; D005786:Gene Expression Regulation / Q000187:drug effects; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009124:Muscle Proteins; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010656:Phenylephrine / Q000494:pharmacology*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction; D000091262:TEA Domain Transcription Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
C491304:ANKRD1 protein, human; D000316:Adrenergic alpha-Agonists; C491303:Ankrd1 protein, rat; D004268:DNA-Binding Proteins; D050991:GATA4 Transcription Factor; D009124:Muscle Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D000091262:TEA Domain Transcription Factors; C057182:TEAD1 protein, human; D014157:Transcription Factors; D010656:Phenylephrine; D008156:Luciferases