Molecular characterization and differential expression of the myostatin gene in Coilia nasus

Estuarine tapertail anchovy (Coilia nasus, junior synonym C. ectenes) is a widely distributed and commercially important aquaculture species, although its growth in aquaculture settings is so slow as to pose a serious practical problem. In order to understand the molecular mechanisms of growth, we cloned the myostatin gene in C. nasus (CnMSTN) by homologous cloning methods. Its full-length cDNA is 2252 bp, with a 1125-bp open reading frame (ORF) that encodes a 374-amino acid protein. The CnMSTN protein is predicted to contain domains typical of MSTN, including a TGFb-propeptide domain and a TGFB domain. Gene expression patterns were detected by RT-qPCR. CnMSTN is expressed strongly in the muscle and brain, and comparatively lower in the gills, liver, spleen, intestine, trunk kidney and head kidney. The effects of stress on the muscle and brain MSTN levels were evaluated by RT-qPCR. CnMSTN in the muscle was positively regulated by loading and transport stress, but brain CnMSTN expression was not affected. We found NaCl could reduce the death rate caused by loading and transporting stress, and in this group, CnMSTN mRNA expression in the muscle revealed increased, but decreased in the brain. Further, in the fasting experiment, the CnMSTN mRNA revealed decrease in the muscle, on the contrary, it showed increase in the brain. Selection upon variants of the MSTN gene has shown great potential in breeding work for mammals, and our results provide the basic knowledge for breeding of C. nasus.