Expression And Purification Of Four Recombinant Neuropeptides Of The Giant Freshwater Prawn Macrobrachium Rosenbergii

Vitellogenin is the precursor of vitellin which specially exists in females in invertebrate and lower vertebrate. Vtellin (Vn) is the major yolk protein stored in crustacean oocytes, where it provides free amino acids, lipids, carbohydrates, carotenoids, and minerals to the growing and development of embryo and larva. Based on the full-length cDNA of Portunu s trituberculatus vitellogenin obtained, the expression pattern of vitellogenin in the crab was characterized by Northern blotting analysis. It was suggested that vitellogenin was mainly expressed in the hepatopancreas and exhibited a stage-related expression manner. Meanwhile, the vitellogenin transcript was also identified in the ovary of the Portunus trituberculatus by reverse transcription- polymerase chain reaction analysisThere are always great concerns on the regulation mechanisms of vitellogenin production in crustaceans. Crustacean Hyperglycemic Hormones (CHH) is a family of hormones which was specifically synthesized in sinus complex of X-organ in crustaceans. The CHH family includes crustacean hyperglycemic hormones (CHH), molting-inhibiting hormones (MIH) and gonad-inhibiting hormones (GIH), and so on. It was suggested that CHH hormones have direct/indirect effects on the gonad maturation and they also regulate the mature and reproductive processes in crustaceans. In the present research, based on the CHH family cDNA sequence(CHH, CHH-L belongs to CHH subtype;Mar-SGP-A, Mar-SGP-B belongs to MIH/VIH subtype) obtained , four expression plasmids, as pET-32a(+)-CHH, pET-32a(+)-CHH-L, pET-32a(+)-Mar-SGP-A and pET-28a(+)-Mar-SGP-B, were constructed and transformed into E.coli BL21(DE3). After induced by IPTG, four peptides were expressed. Then, isolated and purified by using Ni-NTA agarose.