Studies On The Effect Of Neuroparsin1 On Vitellogenesis In The Mud Crab,Scylla Paramamosain

Neuroparsin(NP)is a group of important neuropeptides in invertebrates,which displays multiple biological activities,including antidiuretic and inhibition of vitellogenesis in insects.The mud crab Scylla paramamosain is a commercially important marine crab in China,and the knowledge on reproductive physiological mechanism of which is critical for developing breeding technology of mud crab.In this study,we used S.paramamosain as a model and selected the sequences of Sp-NP1 from transcriptome database.Molecular biological and biochemical technique were applied to explore Sp-NP1 as endocrine factor for the possible regulatory role in vitellogenesis of S.paramamosain.The main research findings of this study are as follows:1)This study analyzed Sp-NP1 amino acid(AA)sequences consisted of a 27 AA signal peptide and a 74 AA mature peptide,which contained 12 cysteine residues.qRT-PCR analysis showed that the expressions of Sp-NP1 gene were high in the nervous tissues and extremely low in the ovary and hepatopancreas.In situ hybridization revealed that the positive signals were localized in cell cluster 6 of protocerebrum and cell clusters 10 and 11 of deutocerebrum when using an antisense probe.Western-Blot detected the presence of Sp-NP1 in the haemolymph from S.paramamosain,which indicated that Sp-NPl served as an endocrine hormone regulating physiological activities.2)In this study,the protein of Sp-NP1 was expressed and purified with the method of prokaryotic expression.In vitro experiments further showed that the mRNA level of vitellogenin(Vg)in the hepatopancreas significantly decreased when added recombinant Sp-NP1 protein(10-7,10-6mol/L),while the mRNA level of vitellogenin receptor(VgR)and cyclin B in ovary had no significant differences compared to controls,respectively.All these data indicated that Sp-NP1 possibly inhibited the production of Vg in the hepatopancreas and had no direct effect on the ovary in S.paramamosain.