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Acta Physiologica 2007; Volume 189, Supplement 653
The 86th Annual Meeting of The German Physiological Society
3/25/2007-3/28/2007
Hannover, Germany
ACTIVATION OF THE B MYOSIN HEAVY CHAIN PROMOTER BY MEF-2D, MYOD, P300, AND CALCINEURIN/NFATC1
Abstract number: S09-2
Meissner1 JD, Umeda2 PK, Chang3 KC, Kubis1,4 HP, Gros1 G, Scheibe1,5 RJ
1Department of Physiology, Hannover Medical School
2Department of Medicine, University of Alabama,
3Division of Animal Production & Public Health, University of Glasgow Veterinary School,
4University of Wales,
5Department of Biochem., Hannover Medical School
C2C12 myotubes predominantly express fast fiber type MHCII and undergo fast-to-slow transformation on the level of MHC promoter activity following calcium ionophore treatment. Transient transfection assays demonstrated that the calcineurin/NFATc1 signaling pathway is essential for MHCß promoter activation. MEF-2D and the myogenic transcription factor MyoD along with NFATc1 transactivated the MHCß promoter in calcium ionophore-treated myotubes in a calcineurin- dependent manner. Also, a calcium ionophore-induced binding of NFATc1 to a NFAT consensus site adjacent to a MyoD-binding E-box in the promoter was detected. At their respective binding sites, both NFATc1 and MyoD recruited the transcriptional coactivator p300. In turn, MEF-2D bound to the MyoD complex. The data demonstrate a calcium-ionophore-induced activation of the MHCß promoter by complex formation of NFATc1, MyoD, MEF-2D, and p300 in a calcineurin-dependent manner.
Supported by DFG grants GR489/13 and -20.
To cite this abstract, please use the following information:
Acta Physiologica 2007; Volume 189, Supplement 653 :S09-2