molecular characterization expression analysis of myostatin gene and its negative regulation by mir29b3p in chinese concaveeared frogs odorrana tormota the molecular characteristics expression patterns and functions of the amphibian myostatin mstn gene are unknown here we isolated a fulllength odorrana tormota mstn cdna sequence of 1701bp otmstn containing a putative nterminal signal peptide a tgf propeptide domain and an active peptide otmstn was expressed in 9 selected tissues examined and the highest level of expression was in thigh muscle followed by brain and female gonadal tissue the expression of otmstn in multiple o tormota tissues supported that the activities of mstn may be not limited to skeletal muscle otmstn expression was decreased from stage 31 to stage 40 while the growth rate was increased the expression of otmstn in adult male frogs increased with age indicating that adult male frogs may inhibit the continued hypertrophy of thigh muscle fibers and decrease the growth rate of thigh muscle to ensure muscles do not grow too large luciferase reporter assays showed that mir29b3p directly targeted the 3utr of otmstn mir29b3p expression in the thigh muscle of 2yrs females who grew faster was significantly lower than that of the slowgrowing 2yrs male individuals which showed an opposite trend with otmstn expression in additionmir29b3p expression reversed trends of otmstn expression at different developmental stages in thigh muscle therefore these data indicate that mir293p may negatively regulate the expression of mstn and regulate thigh muscle growth and development in o tormota