Gene Regulated Melanin Synthesis by Tyrosinase Pathway in .

The paired-box 3 () is a transcription factor and it plays an important part in melanin synthesis. In this study, a new gene was identified from (, ) () by RACE-PCR (rapid-amplification of cDNA ends-polymerase chain reaction) and its effect on melanin synthesis was deliberated by RNA interference (RNAi). The cDNA of was 2250 bp long, containing an open reading fragment of 1365 bp encoding 455 amino acids. Amino acid alignment and phylogenetic tree showed shared the highest (69.2%) identity with of . Tissue expression profile showed that had the highest expression in mantle, a nacre-formation related tissue. The silencing significantly inhibited the expression of , , and , genes involved in -mediated melanin synthesis, but had no effect on and an increase effect on . Furthermore, the knockdown obviously decreased the tyrosinase activity, the total content of eumelanin and the proportion of PDCA (pyrrole-2,3-dicarboxylic acid) in eumelanin, consistent with influence of tyrosinase () knockdown. These data indicated that played an important regulating role in melanin synthesis by pathway in .