Sequence conservation among fish myostatin orthologues and the characterization of two additional cDNA clones from Morone saxatilis and Morone americana

Myostatin (MSTN) negatively regulates mammalian skeletal muscle growth and development by inhibiting myoblast proliferation. Mice and cattle possessin g mutant MSTN alleles display a 'double muscling' phenotype characterized b y extreme skeletal muscle hypertrophy and/or hyperplasia. MSTN orthologues have been previously characterized in 12 vertebrate species, including the white bass Morone chrysops. Presented herein is the identification and char acterization of novel cDNA clones from two additional Morone species: saxat ilis (striped bass) and americana (white perch), which were obtained by PCR amplification and subsequent TA-cloning. The predicted amino acid sequence of each cDNA clone contains a putative signal sequence, conserved cysteine residues and a RXXR proteolytic processing site. The different Morone prot eins were 97-99% identical to each other and approximately 91, 81, 68 and 6 7% identical to the tilapia, zebrafish, mammalian and avian proteins, respe ctively. However, the bioactive domains, which lie downstream of each proce ssing site, were considerably more conserved. They were 99-100% identical w ithin the genus and were approximately 99, 95, 88 and 88% identical to the tilapia, zebrafish, mammalian and avian domains, respectively. This high le vel of sequence conservation among all known MSTN orthologues suggests that the structure/function relationship of each is equally well conserved amon g vertebrates. (C) 2001 Elsevier Science Inc. All rights reserved.