Transcription factor NF1 mediates repression of the GLUT4 promoter by cyclic-AMP.
Prolonged treatment of 3T3-L1 adipocytes with 8-Br-cAMP decreases expression of GLUT4, the insulin-responsive glucose transporter. Expression of a promoter-reporter gene construct that contained 785 base pairs of 5'-flanking region of the murine GLUT4 gene was down regulated by 8-Br-cAMP (p < 0.001), whereas expression of constructs that contained 641 or 469 base pairs of 5'-flanking region was not. A reporter gene construct in which bases -706 to -676 were deleted was not repressed by 8-Br-cAMP, thereby identifying a 30 bp region as necessary for repression of the GLUT4 promoter by 8-Br-cAMP. Mutations in this regulatory element that disrupt binding of the transcription factor NF1 abolish the 8-Br-cAMP-induced repression of the gene. Although insulin and cAMP both repress the GLUT4 promoter through this cis-element, they appear to do this through different mechanisms, as treatment with 8-Br-cAMP does not induce the phosphorylation of NF1 that is induced by insulin treatment.
Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21287-2520, USA. dcooke@welchlink.welch.jhu.edu
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D016475:3T3 Cells; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology*; D017667:Adipocytes / Q000166:cytology / Q000187:drug effects; D000818:Animals; D001483:Base Sequence; D005576:Colforsin / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects*; D017930:Genes, Reporter / Q000235:genetics; D051275:Glucose Transporter Type 4; D007328:Insulin / Q000494:pharmacology; D051379:Mice; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D009124:Muscle Proteins; D009154:Mutation; D051839:NFI Transcription Factors; D009687:Nuclear Proteins / Q000378:metabolism; D009841:Oligonucleotides / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D020218:Response Elements / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism*
D004268:DNA-Binding Proteins; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D009841:Oligonucleotides; D012333:RNA, Messenger; C495693:Slc2a4 protein, mouse; D014157:Transcription Factors; C080333:transcription factor nuclear factor 1; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate