SAGI, A.*; KHALAILA, I.; AFLALO, E.; PETER-KATALINIC, J.; ABDU, U.; DAVIS, C.; Ben Gurion University, Beer Sheva, Israel; University of Muenster, Germany; Ben Gurion University, Beer Sheva, Israel; University of Muenster, Germany; Princeton University; Ben Gurion University, Beer Sheva, Israel: The vitellogenin gene in the crayfish Cherax quadricarinatus: expression and encoded proteins

A vitellogenin complete cDNA of the crayfish Cherax quadricarinatus (CqVg) was cloned and sequenced in our laboratory (Genbank accession number AF306784). The CqVg gene was found to be expressed in the hepatopancreas of secondary-vitellogenic females and intersex individuals. In the female hepatopancreas CqVg was normally expressed with the onset of vitellogenesis while in sexually plastic intersex animals expression was induced only following the removal of the androgenic gland. Sequence similarities between the complete deduced amino acid sequence of the CqVg cDNA and its presumable high density lipoprotein products, i.e. vitellogenin in the hemolymph and vitellin in the ovary were examined. The different proteins, presumably vitellogenins, found in the hemolymph (predominantly 208, 196, 177 and 80 kDa) and the different components of the yolk protein vitellin found in the ovary (predominantly 177, 155, 106, 95, 86, 75) were separated and compared. The similarity found suggested that proteins from both locations are products of the same CqVg gene. A tentative scheme is suggested including gene expression, possible alternative splicing and product formation, describing the route of yolk protein precursors in C. quadricarinatus from the hepatopancreas through the circulation till its final accumulation in the oocyte.