Developmental expression and alternative splicing of the duck myostatin gene

Myostatin (MSTN) plays a key role in the negative regulation of muscle growth and development during embryogenesis. The MSTN genes have different genetic characteristics in vertebrates: sole gene in mammals, gene duplication in fish, and alternative splicing in birds. To investigate the alternative splicing sites and developmental expression patterns of the duck MSTN genes, the mRNA and genome sequences were cloned, and the expression patterns were detected during breast muscle and leg muscle development by real-time PCR. In our study, four alternatively spliced forms of MSTN mRNA were found in the developing skeletal muscle of Peking duck, including two novel alternatively spliced transcripts, MSTN-c and MSTN-d. As a result of alternative splicing at the common GT-AG processing sites, MSTN-b and MSTN-c retained only the N-terminal TGFβ-propeptide superfamily domains. However, MSTN-d was not missing these domains, in contrast to MSTN-a. The real-time PCR results showed that there was no significant difference between breast muscle and leg muscle in MSTN-a mRNA expression, also in MSTN-b and MSTN-c. MSTN-a and MSTN-b have significant higher expressions than MSTN-c and MSTN-d, suggesting that they play the major role during embryo muscle development.