Molecular Characteristics and Abundance of Insulin-like Androgenic Gland Hormone and Effects of RNA Interference in Eriocheir Sinensis

Insulin-like androgenic gland hormone (IAG) has an important function in sexual differentiation and somatic growth in crustaceans. In this study, there was cloning of the full-length sequence of IAG from Eriocheir sinensis (Es-IAG). The full-length Es-IAG gene was 1392 base pairs long and encoded a protein of 151 amino acid residues. The precursor peptide included a signal peptide, and the protein was a protein that is secreted from the cell in which it is produced with no transmembrane domain. Amino acid sequence alignment indicated there was the greatest homology between E. sinensis and Chaceon quinquedens (47 %), followed by Callinectes sapidus (44 %). Results from analysis of the relative abundances of Es-IAG mRNA transcript at different developmental stages indicated that Es-IAG may have an important endocrine function in early embryonic development, and that Stages I through Ⅲ may be an important period for sexual differentiation in juvenile E. sinensis. In vivo treatment with siRNA-391 resulted in a 66.7 % lesser relative abundance of the Es-IAG mRNA transcript. Three treatments with siRNA-391 to inhibit Es-IAG production during Stages Ⅲ to Ⅴ period resulted in about 10 % of male crabs being transformed into "neo-females." These results provide the basis for further research into the sexual differentiation mechanism and monosex breeding of E. sinensis.