Identification of a skeletal muscle-specific regulatory domain in the rat GLUT4/muscle-fat gene

J. M. Richardson, J. E. Pessin

Research output: Contribution to journalArticle

55 Scopus citations

Abstract

To identify sequences responsible for the muscle-specific expression of the rat GLUT4/muscle-fat gene, we examined the transcriptional regulation of this gene in the differentiating murine C2C12 skeletal muscle cell line. Differentiated myofibers displayed a 4-5-fold increase in GLUT4 mRNA compared with undifferentiated myoblasts which paralleled the conversion from non- muscle β-actin mRNA to muscle-specific α-actin mRNA expression. Transient transfection of progressive 5' and 3' deletions of the GLUT4 5'-flanking DNA identified a 281-base pair region located between -517 and -237 relative to the transcription start site which conferred myotube-specific expression. This region increased reporter activity in the context of the GLUT4 minimal promoter in an orientation-independent manner and, in addition, onto the heterologous thymidine kinase promoter. Myotube-specific expression of both GLUT4 reporter constructs and the endogenous mouse GLUT4 mRNA was also observed to be thyroid hormone-dependent. Further, cotransfection of reporter constructs containing the 281-base pair GLUT4 differentiation-specific enhancer with the thyroid hormone receptor specifically increased luciferase activity in myotubes approximately 12-fold. Thus, these data demonstrate the presence of a proximal skeletal muscle-specific activation domain that is necessary for both myotube-specific GLUT4 expression and thyroid hormone responsiveness.

Original languageEnglish (US)
Pages (from-to)21021-21027
Number of pages7
JournalJournal of Biological Chemistry
Volume268
Issue number28
StatePublished - Jan 1 1993
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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