Identification and expression of an ecdysteroid-responsive amylase from red crayfish Procambarus clarkii

Amylases catalyze the hydrolysis of starch material and play important roles in the regulation of many physiological processes. Here, we report an amylase gene denoted Pc - Amy in the crayfish Procambarus clarkii (Decapoda: Cambaridae). The Pc - Amy gene encodes a polypeptide of 514 amino acids, and the deduced amylase protein is highly homologous to those from crustaceans. Real-time quantitative reverse transcription PCR (qRT-PCR) analysis showed that Pc - Amy is highly expressed in hepatopancreas during the intermolt period. SDS-PAGE and western blot analysis demonstrated that a 58-kDa recombinant protein is successfully expressed in Escherichia coli cells. The expression of Pc - Amy was significantly downregulated in hepatopancreas at 48 h after ecdysteroid induction, as confirmed by qRT-PCR and western blot analyses. In addition, RNA interference with the ecdysteroid receptor had an impact on the expression of Pc - Amy . These results suggest that Pc - Amy is an ecdysteroid-responsive gene which plays a role in the developmental process of P. clarkii .