Using DNA microarray to identify Sp1 as a transcriptional regulatory element of insulin-like growth factor 1 in cardiac muscle cells.
High throughput gene expression profiling with DNA microarray provides an opportunity to analyze transcriptional regulation of hundreds or thousands of similarly regulated genes. Transcriptional regulation of gene expression plays an important role in myocardial remodeling. We have studied cardiac muscle gene expression with DNA microarray and used a computational strategy to identify common promoter motifs that respond to insulin-like growth factor 1 (IGF-1) stimulation in cardiac muscle cells. The analysis showed that the Sp1 binding site is a likely target of IGF-1 action. Further experiments with gel shift assay indicated that IGF-1 regulated the Sp1 site in cardiomyocytes, by increasing the abundance of Sp1 and Sp3 proteins. Using firefly luciferase as reporter gene, additional experiments showed that IGF-1 activated the promoter of cyclin D3 and Glut1. Both promoters contain one Sp1 site. The effect of IGF-1 on these two promoters was abolished with siRNA for Sp1. Thus, the transcriptional activation of these two promoters by IGF-1 requires the induction of Sp1 protein. These experiments suggest that the global transcriptional regulatory actions of IGF-1 involve activation of the Sp1 site in cardiac muscle. The computational model we have developed is a prototypical method that may be further developed to identify unique cis- and trans-acting elements in response to hormonal stimulation during cardiac muscle growth, repair, and remodeling in normal and abnormal cardiac muscle.
Department of Medicine, Center for Cardiovascular Hormone Research, University of California, Irvine, Calif, USA.
Tao
T
Li
Yung-Hsiang
YH
Chen
Tsun-Jui
TJ
Liu
Jia
J
Jia
Steven
S
Hampson
Yue-Xin
YX
Shan
Dennis
D
Kibler
Ping H
PH
Wang
D000818:Animals; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D056743:Cyclin D3; D016213:Cyclins / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation / Q000187:drug effects; D051272:Glucose Transporter Type 1; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000235:genetics; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D009841:Oligonucleotides / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D051705:Sp3 Transcription Factor; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics; D014162:Transfection; D015854:Up-Regulation / Q000187:drug effects
C534696:CCND3 protein, human; C534698:Ccnd3 protein, rat; D056743:Cyclin D3; D016213:Cyclins; D004268:DNA-Binding Proteins; D051272:Glucose Transporter Type 1; D009004:Monosaccharide Transport Proteins; D009841:Oligonucleotides; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; C495677:SLC2A1 protein, human; C497121:SP3 protein, human; C495679:Slc2a1 protein, rat; D016329:Sp1 Transcription Factor; C497123:Sp3 protein, rat; D014157:Transcription Factors; D051705:Sp3 Transcription Factor; D007334:Insulin-Like Growth Factor I; D008156:Luciferases