Abstract
We report tripartite co-operation between MyoD, myocyte enhancer factor-2 (MEF2) and the thyroid hormone receptor (TRα1) that takes place in the context of an 82-bp muscle-specific enhancer in the rat insulin-responsive glucose transporter (GLUT4) gene that is active in both cardiac and skeletal muscle. In the L6E9 skeletal muscle cell line and in 10T1/2 fibroblasts, a powerful synergistic activation of the GLUT4 enhancer relied on the over-expression of MyoD, MEF2 and TRα1 and the integrity of their respective binding sites, and occurred when linked to either a heterologous promoter or in the context of the native GLUT4 promoter. In cardiac myocytes, enhancer activity was dependent on the binding sites for MEF2 and TRα1. Furthermore, we show that in 10T1/2 fibroblasts, the forced expression of MyoD, MEF2 and TRα1 induced the expression of the endogenous, otherwise silent, GLUT4 gene. In all, our results indicate a novel functional co-operation between these three factors which is required for full activation of GLUT4 transcription.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.