Localization of exercise- and denervation-responsive elements in the mouse GLUT4 gene.
Exercise training increases the expression of GLUT4 in skeletal muscle. Previous studies demonstrated that the exercise-responsive element(s) of the murine GLUT4 gene are located between bases -1001 and -442 relative to the transcription start site. To further characterize the regulatory elements in the GLUT4 gene, the regulation of GLUT4 minigenes containing -701, -551, -442, or -423 bp of the 5'-flanking region was studied in transgenic mice. All minigenes studied showed significant expression in skeletal muscle and heart, including the -423 GLUT4 minigene that lacked the myocyte enhancer factor 2 (MEF2)-binding domain (-CTAAAAATAG-) located between bases -437 and -428. The -701- and -551-bp constructs were expressed in brown adipose tissues while the -442 and -423 constructs were not. In skeletal muscle, either swimming or treadmill running up-regulated GLUT4 minigene mRNA levels in -701 and -551 transgenic mice, but not in the -442 and -423 transgenic mice. Denervation of the gastrocnemius muscle by sectioning of the sciatic nerve down-regulated minigene and endogenous GLUT4 mRNAs in all -701, -551, -442, and -423 transgenic mice. These data indicate that exercise-responsive element(s) and brown adipocyte specific element(s) are located within 109 bp between bases -551 and -442 of the GLUT4 gene, but that the cis-element for denervation-induced down-regulation of the GLUT4 gene is located downstream of base -423. Finally, the MEF2 binding site between bases -437 and -428 is not necessary for expression of GLUT4 in skeletal muscles and heart; the cis-element mediating this effect is also located downstream of base -423.
Tsunoda
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N
Division of Clinical Nutrition, National Institute of Health and Nutrition, 1-23-1 Toyama, Shinjuku-ku, Tokyo, 162-8636, Japan.
Maruyama
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K
Cooke
D W
DW
Lane
D M
DM
Ezaki
O
O
D020121:5' Untranslated Regions / Q000235:genetics; D000818:Animals; D005786:Gene Expression Regulation; D051275:Glucose Transporter Type 4; D051379:Mice; D008822:Mice, Transgenic; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D009121:Muscle Denervation; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D009928:Organ Specificity; D010805:Physical Conditioning, Animal / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D012584:Sciatic Nerve / Q000502:physiology; D017384:Sequence Deletion; D014158:Transcription, Genetic
D020121:5' Untranslated Regions; D051275:Glucose Transporter Type 4; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; C495693:Slc2a4 protein, mouse