Myocyte enhancer factor 2 (MEF2)-binding site is required for GLUT4 gene expression in transgenic mice. Regulation of MEF2 DNA binding activity in insulin-deficient diabetes.
We have previously demonstrated that important regulatory elements responsible for regulated expression of the human GLUT4 promoter are located between -1154 and -412 relative to transcription initiation (Olson, A. L., and Pessin, J. E. (1995) J. Biol. Chem. 270, 23491-23495). Through further analysis of this promoter regulatory region, we have identified a perfectly conserved myocyte enhancer factor 2 (MEF2)-binding domain (-CTAAAAATAG-) that is necessary, but not sufficient, to support tissue-specific expression of a chloramphenicol acetyltransferase reporter gene in transgenic mice. Biochemical analysis of this DNA element demonstrated the formation of a specific DNA-protein complex using nuclear extracts isolated from heart, hindquarter skeletal muscle, and adipose tissue but not from liver. DNA binding studies indicated that this element functionally interacted with the MEF2A and/or MEF2C MADS family of DNA binding transcription factors. MEF2 DNA binding activity was substantially reduced in nuclear extracts isolated from both heart and skeletal muscle of diabetic mice, which correlated with decreased transcription rate of the GLUT4 gene. MEF2 binding activity completely recovered to control levels following insulin treatment. Together these data demonstrated that MEF2 binding activity is necessary for regulation of the GLUT4 gene promoter in muscle and adipose tissue.
Thai
M V
MV
Department of Biochemistry and Molecular Biology, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190, USA.
Guruswamy
S
S
Cao
K T
KT
Pessin
J E
JE
Olson
A L
AL
D000818:Animals; D001665:Binding Sites / Q000235:genetics; D017124:Conserved Sequence / Q000235:genetics; D004268:DNA-Binding Proteins / Q000502:physiology*; D003921:Diabetes Mellitus, Experimental / Q000235:genetics; D004742:Enhancer Elements, Genetic / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics*; D017930:Genes, Reporter / Q000235:genetics; D051275:Glucose Transporter Type 4; D006801:Humans; D026161:MADS Domain Proteins; D064326:MEF2 Transcription Factors; D051379:Mice; D008822:Mice, Transgenic; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D009124:Muscle Proteins; D018006:Myogenic Regulatory Factors / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*
D004268:DNA-Binding Proteins; D051275:Glucose Transporter Type 4; D026161:MADS Domain Proteins; D064326:MEF2 Transcription Factors; C578035:MEF2A protein, human; C578040:MEF2C protein, human; C578036:Mef2a protein, mouse; C578041:Mef2c protein, mouse; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D018006:Myogenic Regulatory Factors; D009687:Nuclear Proteins; D012333:RNA, Messenger; C495692:SLC2A4 protein, human; C495693:Slc2a4 protein, mouse; D014157:Transcription Factors