A novel second myostatin gene is present in teleost fish.

We report on the isolation and characterisation of the complete cDNA sequence encoding a novel bone morphogenetic protein-like protein (sbMSTN-b) in the teleost fish Sparus aurata. The encoded protein is 68% identical to S. aurata MSTN at the amino acid level, and homologues were also found in Umbrina cirrosa and Tetraodon nigroviridis. Phylogenetic analysis suggests that the MSTN-b gene may be present in most, perhaps all, teleost fish species. RT-PCR on different tissues/stages indicates that MSTN-b is expressed almost exclusively in the central nervous system, starting from late larval stages. Quantitative analyses indicate an increase of sbMSTN-b expression in the brain associated with metamorphosis, at the same time as completion of nervous system differentiation.