Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: 3/19/2005
Publication Date: 3/19/2005
Citation: Salem, M., Yao, J., Rexroad III, C.E., Kenney, B., Semmens, K., Killefer, J., Nath, J. 2005. Molecular characterization of calpastatins from rainbow trout: their role in muscle growth and fillet texture development. Aquaculture America Conference 2005 page 388.
Technical Abstract: Calpastatin (CAST) is a specific inhibitor of the calpain proteases that play a significant role in steady-state muscle protein turnover during animal growth and postmortem whole-muscle food tenderization. In rainbow trout, we identified cDNAs for long (CAST-L) and short (CAST-S)isoforms. Translation of CAST-L cDNA (2600 bp) predicted 497 amino acids with an expected MW of 52.5 KDa. CAST-S showed 2 splice variants; variant 1 (2132 bp) encodes for 296 amino acids with expected MW of 31.5 KDa and variant 2 (2246 bp) with a premature stop signal, encodes for 154 amino acids with a expected MW of 16.3 KDa. Rainbow trout CASTs were used to retrieve a homologous cDNA sequence from zebra fish. The rainbow trout CAST-L showed 19 and 44% amino acid sequence identity with mouse and zebra fish CASTs, respectively, and CAST-S variant 2 exhibited 25 and 51% identity, respectively. Fish CASTs are novel in possessing the fewer number, two of the four, of the highly repetitive inhibitory domains reported thus far. Expression of CAST messenger RNA was measured by real time RT-PCR in 3 rainbow trout strains differing in growth rate and fillet firmness. Fish were fed high or low energy diets. CAST-L and S expressions were higher in fish strains with faster growth rates and firmer fillets. Energy content of the diet did not affect CAST expression. These results provide insight into the potential use of the CAST gene as a biogenetic tool for monitoring the fish muscle growth and texture quality.