Differential gene expression in hepatopancreas of the shrimp Metapenaeus ensis during ovarian maturation.

Differentially expressed genes were identified in the hepatopancreas of Metapenaeus ensis during ovarian maturation via differential display reverse transcription-polymerase chain reaction (DDRT-PCR). They are G-protein signaling modulator 2 (GPSM2), glutamate carboxypeptide II (GCPII), ligatin, C-type lectin, O-linked N-acetylglucosamine transferase (O-GlcNAc transferase), 1-acylglycerol-3-phosphate O-acyltransferase 4 (AGPAT4), vitellogenin (Vg), and hemocyanin. The hepatopancreas Vg gene identified in this study shows 92% and 49% amino acid sequence homology, respectively, to MeVg1 and MeVg2 previously isolated from this species, suggesting the identification of a new Vg gene in M. ensis. Vg gene expression was highest when the ovary was actively developing. The two metabolic enzymes, O-GlcNAc transferase and AGPAT4, exhibited a similar trend of expression to Vg gene, suggesting their involvement in Vg synthesis. The signal transduction related genes (GPSM2, GCPII, ligatin, and C-type lectin) were highly expressed in the hepatopancreas in the initial phase of maturation. These genes may be important for the signaling in the hepatopancreas for synthesis and mobilization of vitellogenin and nutrients to the developing ovary. The present work provides candidate genes for further investigation on the role of hepatopancreas in shrimp reproduction.