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Different pathways regulate expression of the skeletal myosin heavy chain genes
Different pathways regulate expression of the skeletal myosin heavy chain genes.
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Mammalian skeletal muscles are a mosaic of different fiber types largely defined by differential myosin heavy chain (MyHC) expression. Little is known about the molecular mechanisms regulating expression of the MyHC gene family members in different fiber types. In this work, we identified several cis- and trans-elements that regulate expression of the three adult fast MyHC genes. Despite multiple DNA-binding motifs for well characterized muscle transcription factors upstream of all three fast MyHC genes, expression of MyoD/Myf-5, calcineurin, or NFAT3 had different effects on the three promoters. MyoD or Myf-5 overexpression preferentially activated the IIb promoter, whereas NFAT or activated calcineurin overexpression preferentially activated the IIa promoter. Calcineurin had a 50-100-fold stimulatory effect on the IIa promoter, and the known downstream effectors of calcineurin (myocyte enhancer factor-2 and NFAT) cannot completely account for this activation. Finally, we identified two elements critical for regulating MyHC-IId/x expression: a 130-base pair enhancer element and a CArG-like element that inhibited IId/x promoter activity in vitro. Thus, we have found specific regulatory pathways that are distinct for the three adult fast MyHC genes. These elements are logical candidates for fiber-specific control of skeletal muscle gene expression in vivo.
Allen DL, Sartorius CA, Sycuro LK, Leinwand LA
The Journal of biological chemistry
2001-11-23 00:00
276
47
43524-33
Animals,Base Sequence,Cell Line,DNA,Enhancer Elements (Genetics),Gene Expression Regulation,Mice,Molecular Sequence Data,Muscle, Skeletal,Myosin Heavy Chains,Promoter Regions (Genetics),Myosin Heavy Chains,DNA
Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347, USA
J. Biol. Chem.
NIAMS F32AR08443, NIGMS R01-GM29090
0021-9258
10.1074/jbc.M108017200
M108017200
705
True
11551968
