Identification and characterization of a doublesex gene which regulates the expression of insulin-like androgenic gland hormone in Fenneropenaeus chinensis.

The doublesex and its homologue genes are important regulators of sexual differentiation which are conserved among animal kingdom. In the present study, we reported a doublesex gene (designated as FcDsx) identified from the Chinese shrimp F. chinensis. The gene structure, nucleotide and deduced amino acid sequences of FcDsx were characterized. The results showed that the deduced amino acid sequence of FcDsx had the common features of Dsx proteins, including a doublesex/male abnormal 3 (DM) domain, an oligomerization domain and a predicted monopartite nuclear localization signal. The expression patterns of FcDsx in different tissues and developmental stages were detected. FcDsx exhibited a sex-biased expression patterns in different tissues and its expression level increased along with developmental stages. In addition, its regulation on the expression of FcIAG, a gene important for sexual differentiation of male crustacean, was also analyzed. Putative Dsx binding site was identified on the promoter region of FcIAG and knockdown of FcDsx could reduce the expression of FcIAG, which suggested that FcDsx might be the upstream regulator of FcIAG. The present data indicated that FcDsx gene might involve in shrimp sexual differentiation process.