Increased Levels of Mitochondrial ATP Synthase β-Subunit in Fast Skeletal Muscle of Carp Acclimated to Cold Temperature

Abstract

We compared two-dimensional electrophoretic patterns of cytosolic extracts from fast muscle of the 10°C- and 30°C-acclimated carp Cyprinus carpio, and revealed that cold acclimation resulted in an approximately two-fold increase of the expression levels of a 55-kDa protein. This protein was identified as mitochondrial ATP synthase β-subunit by N-terminal amino acid sequencing after electrophoresis along with subsequent cDNA cloning. A full-length cDNA clone of carp ATP synthase β-subunit encoded 518 amino acids, showing 72-89% identity to those of eukaryotes at the level of amino acid sequence. The accumulated levels of ATP synthase β-subunit transcripts in the fast muscle from the 10βC- and 30βC-acclimated carp were well correlated with those at the protein level, suggesting that expression of this protein during temperature acclimation is regulated mainly at the transcription level.