Cloning and characterization of a cDNA encoding a paired box protein, PAX7, from black sea bream, Acanthopagrus schlegelii

Paired box protein, PAX7, is a key molecule for the specification, maintenance and skeletal muscle regeneration of muscle satellite cells. In this study, we identified and characterized the cDNA and amino acid sequences of PAX7 from black sea bream (Acanthopagrus schlegelii) via molecular cloning and sequence analysis. A. schlegelii PAX7 cDNA was comprised of 1,524 bp encoding 507 amino acids and multiple sequence alignment analysis of the translated amino acids showed that it contained three domains including paired DNA-binding domain, homeobox domain and OAR domain which were well conserved across various animal species investigated. Pairwise Sequence Alignment indicated that A. schlegelii PAX7 had the same amino acid sequences with that of yellowfin seabream (A. latus) and 99.8% identity and similarity with that of gilt-head bream (Sparus aurata). Molecular phylogenetic analysis confirmed that A. schlegelii PAX7 formed a monophyletic group with those of teleost and most closely related with those of the fish that belong to Sparidae family including A. latus and S. aurata. In the investigation of its tissue specific mRNA expression, the expression was specifically identified in skeletal muscle tissue and a weak expression was also shown in gonad tissue. The cultured cells derived from skeletal muscle tissues expressed PAX7 mRNA at early passage but the expression was not observed after several times of subculture.