Myostatin in black Muscovy duck (<i>Cairina moschata</i>): full-length cDNA cloning and age-dependent mRNA expression compared with <i>IGF-I</i>

<p></p><p>Insulin-like growth factor-I (<i>IGF-I</i>) and myostatin (<i>MSTN</i>) are a pair of critical positive and negative growth regulators. The aim of the current study was to examine the age-dependent and muscle-specific expression of <i>IGF-I</i> and <i>MSTN</i> mRNAs in black Muscovy ducks in order to understand their roles in regulating the postnatal muscle growth of domestic ducks.</p><p>The full-length cDNA of the black Muscovy duck <i>MSTN</i> gene was cloned and the age-dependent mRNA expression profile was compared with that of the <i>IGF-I</i> mRNA in skeletal muscles.</p><p>The cDNA sequence of the <i>MSTN</i> gene was 1128 bp in length and encodes 375 amino acids, with more than 94.9% homology with poultry <i>MSTN</i> genes, and 83.0–92.0% homology with that of human and mammals (accession: KR006339.1).</p><p>The <i>IGF-I</i> and <i>MSTN</i> mRNA expression exhibited opposite trends in age-dependency and in different muscles: <i>IGF-I</i> mRNA level was high in the early postnatal stage and low in the late mature stage, corresponding positively to growth; while the <i>MSTN</i> mRNA was low in the early stage, increased gradually and reached the highest level in mature muscles, and was negatively related to muscle growth. In the breast muscles, <i>IGF-I</i> mRNA was much higher than in the leg muscles; the opposite effect was seen in <i>MSTN</i> mRNA.</p><p>These data suggest that the relative expression levels of <i>IGF-I</i> and <i>MSTN</i> are essential determinants in the temporal and muscle-specific regulation of postnatal skeletal muscle growth in Muscovy duck and possibly in other poultry species as well.</p><p></p> <p>Insulin-like growth factor-I (<i>IGF-I</i>) and myostatin (<i>MSTN</i>) are a pair of critical positive and negative growth regulators. The aim of the current study was to examine the age-dependent and muscle-specific expression of <i>IGF-I</i> and <i>MSTN</i> mRNAs in black Muscovy ducks in order to understand their roles in regulating the postnatal muscle growth of domestic ducks.</p> <p>The full-length cDNA of the black Muscovy duck <i>MSTN</i> gene was cloned and the age-dependent mRNA expression profile was compared with that of the <i>IGF-I</i> mRNA in skeletal muscles.</p> <p>The cDNA sequence of the <i>MSTN</i> gene was 1128 bp in length and encodes 375 amino acids, with more than 94.9% homology with poultry <i>MSTN</i> genes, and 83.0–92.0% homology with that of human and mammals (accession: KR006339.1).</p> <p>The <i>IGF-I</i> and <i>MSTN</i> mRNA expression exhibited opposite trends in age-dependency and in different muscles: <i>IGF-I</i> mRNA level was high in the early postnatal stage and low in the late mature stage, corresponding positively to growth; while the <i>MSTN</i> mRNA was low in the early stage, increased gradually and reached the highest level in mature muscles, and was negatively related to muscle growth. In the breast muscles, <i>IGF-I</i> mRNA was much higher than in the leg muscles; the opposite effect was seen in <i>MSTN</i> mRNA.</p> <p>These data suggest that the relative expression levels of <i>IGF-I</i> and <i>MSTN</i> are essential determinants in the temporal and muscle-specific regulation of postnatal skeletal muscle growth in Muscovy duck and possibly in other poultry species as well.