Identification of an additional vitellogenin gene showing hepatopancreas-specific expression in the kuruma prawn Marsupenaeus japonicus

Recent research on decapod crustaceans revealed the presence of multiple vitellogenin genes within a single species. Characterizing their expression dynamics and regulatory mechanisms is helpful for the sustainability of commercially relevant decapods through a greater comprehension of vitellogenesis. However, it is unclear whether multiple vitellogenin genes exist in the kuruma prawn Marsupenaeus japonicus , an essential species in several Asian countries. This study determined the full-length cDNA sequence of the new vitellogenin (Maj-Vg2) using transcriptome analysis and cDNA cloning. The deduced Maj-Vg2 consisted of 2,554 amino acids and shared only 53.8% identity with Maj-Vg1, the known vitellogenin of this species. The Maj-Vg1 gene ( Maj-Vg1 ) was expressed in both the hepatopancreas and ovary, whereas the Maj-Vg2 gene ( Maj-Vg2 ) was expressed only in the hepatopancreas. Maj-Vg2 expression in the hepatopancreas was low during the previtellogenic stage and increased during the early and late yolk globule stages . When eyestalks were ablated from immature prawns, Maj-Vg2 expression in the hepatopancreas increased significantly, like Maj-Vg1 expression in the ovary, suggesting possible regulation by hormones from the eyestalk ganglia. These results suggested that Maj-Vg2 and Maj-Vg1 are involved in vitellogenesis in this species .