Cloning of the full-length coding sequence and expression analysis of Sox9b in guppy (Poecilia reticulata)

Sox9 is an SRY-related testis-determining gene. It has been identified in different species, thereby testifying to its conserved role in evolution. In this study, we isolated and characterized the guppy sox9b coding sequence and then analyzed its expression pattern in various adult guppy tissues by reverse transcription (RT)-PCR. The guppy sox9b encoded a 480-amino acid (aa) protein containing a SOX-TCF_HMG-box from aa 103 to 174 in the N-terminus region. The predicted molecular weight and the isoelectric point of this protein were 52.7 kDa and 6.61, respectively. The deduced amino acid sequence of guppy Sox9b showed 91.0% similarity to that of Oryzias latipes and 88.3% similarity to that Gasterosteus aculeatus. The detection of Sox9b mRNA in both the testis and ovary suggests that this gene might be involved in the gonad development of guppy.