A sequence element in the GLUT4 gene that mediates repression by insulin.
Prolonged treatment of 3T3-L1 adipocytes decreases expression of GLUT4, the insulin-responsive glucose transporter. Expression of promoter-reporter gene constructs that contained 2900 or 785 base pairs of 5'-flanking region of the murine GLUT4 gene was down-regulated by insulin (p < 0.0005), whereas expression of constructs that contained 641, 469, or 78 base pairs of 5'-flanking region was not. Nuclear extract from 3T3-L1 adipocytes protected the region from -707 to -681 in the GLUT4 5'-flanking region from DNase I digestion. Using an oligonucleotide probe that corresponded to this footprinted region, two major protein-DNA complexes were identified by a gel mobility shift assay. Southwestern analysis identified four protein bands with molecular masses from 38 to 46 kDa that bound to the insulin-responsive region probe. A reporter gene construct in which bases -706 to -676 were deleted was not repressed by insulin treatment, confirming that this sequence is necessary for the repression of the GLUT4 promoter by insulin in 3T3-L1 adipocytes. This sequence does not show homology to previously described insulin response elements and thus represents a distinct mechanism of gene regulation by insulin.
Cooke
D W
DW
Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-3311, USA. dcooke@welchlink.welch.jhu.edu
Lane
M D
MD
D017667:Adipocytes; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism; D015536:Down-Regulation; D017930:Genes, Reporter; D051275:Glucose Transporter Type 4; D007328:Insulin / Q000494:pharmacology*; D051379:Mice; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis / Q000235:genetics*; D009124:Muscle Proteins; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism; D011485:Protein Binding; D012045:Regulatory Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid
D004268:DNA-Binding Proteins; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D009687:Nuclear Proteins; C495693:Slc2a4 protein, mouse