Abstract

The eyestalk of crustaceans is a vital neuroendocrine organ complex that regulates various important physiological processes, especially molting and reproduction. The mandibular organ-inhibiting hormone (MOIH), an important member of the crustacean hyperglycemic hormone (CHH) neuropeptide family, mediates vitellogenesis and reproduction. In this study, EsMOIH was isolated from the eyestalk of Eriocheir sinensis . Sequence analysis suggested that EsMOIH belongs to CHH subfamily II and contains a conserved CHH/molt-/vitellogenesis-inhibiting hormone (MIH/VIH) domain and six conserved cysteines forming three disulfide bonds. The findings corroborated the results of phylogenetic analysis. Quantitative polymerase chain reaction (qPCR) analysis suggested that EsMOIH was ubiquitously expressed in all the examined tissues, but was highly specifically expressed in the hepatopancreas. The hepatopancreatic transcription of EsMOIH decreased significantly at stages III and IV, but increased thereafter and was highest at stage V. EsMOIH transcription was strongly negatively correlated with the hepatopancreatic expression of vitellogenin ( EsVg ), suggesting that EsMOIH could partake in inhibiting vitellogenesis in the hepatopancreas of E. sinensis . The RNA interference (RNAi)-mediated specific knockdown of EsMOIH significantly reduced EsMOIH expression in vitro and in vivo, but markedly increased EsVg expression in the ovary and hepatopancreas. Altogether, the results suggested that EsMOIH partakes in inhibiting vitellogenesis in E. sinensis .