Peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1 alpha) expression and the formation of slow-twitch muscle fibers in porcine and bovine skeletal muscles
2005
Chikuni, K.(National Inst. of Livestock and Grassland Science, Tsukuba, Ibaraki (Japan)) | Nakajima, I. | Oe, M. | Muroya, S.
The peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC-1 alpha) induces mitochondria biogenesis in skeletal muscles. To determine the relationships between PGC-1 alpha and the muscle fiber types, the expression levels of PGC-1 alpha were analyzed in porcine and bovine skeletal muscles. As a first step, the nucleotide sequences of the porcine and bovine PGC-1 alpha were determined. The porcine and bovine PGC-1 alpha cDNA encoded 796 amino acid sequences and showed 95.1% identity between the two species. The expression levels of the PGC-1 alpha mRNA were analyzed in the same 10 skeletal muscles from four pigs and three cattle. The contents of porcine and bovine PGC-1 alpha were higher in the tongue, masseter and diaphragm, and lower in the Biceps femoris, semimembranosus, Longissimus thoracis and semitendinosus muscles. The contents of myosin heavy chain slow-type protein (MyHC-slow) were also determined in the same muscles by ELISA. The analysis of MyHC-slow showed results similar to those for the PGC-1 alpha contents in all of the muscles except for the tongue. The content of MyHC-slow in the tongue was the lowest among the porcine muscles, and moderate among the bovine muscles. The results suggest that PGC-1 alpha relates to the development of oxidative muscle fibers, but is not the principal factor in determining type 1 fiber content.
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