Two genes with fertile attributes from Macrobrachium nipponense (De Haan, 1849) (Natantia: Palaemonidae): Evidence from expression analysis of Mago nashi and Tsunagi proteins during oocyte maturation and embryonic development

Mago nashi (Mago) and Tsunagi (Y14) are the core components of the exon junction complex that play important roles in RNA metabolism and development of eukaryotic organisms. We identified two cDNAs encoding Mago and Tsunagi protein from the oriental river prawn Macrobrachium nipponense (De Haan, 1849) and termed MnMago and MnTsu, respectively. The MnMago cDNAs encoded a 147-amino-acid protein with an obvious "Mago nashi" domain. The MnTsu cDNA encoded a 161-amino-acid protein with a conserved RNA recognition motif. Prediction of interaction modeling showed that Mago and Tsunagi proteins formed a Mago-Tsunagi dimer complex, indicating that the two genes may play a biological function through the Mago-Tsunagi protein complex in M. nipponense. Real-time quantitative PCR analyses showed that the expressions of MnMago and MnTsu in the ovary were consistent among developmental stages. The expression gradually increased from perinucleolus- to oil-globule stage, and reached the peak at the secondary vitellogenesis stage. After a sharp decrease at oocyte maturation stage, the expressions bounced back at the paracmasis stage. The expression patterns of the two transcripts were also synchronized with embryonic development. The highest expression appeared at the protozoea stage, suggesting that MnMago and MnTsu play an important role in the process of embryogenesis. The Mago and Tsunagi cDNA sequences were sequenced from the oriental river prawn for the first time and the pattern of gene expressions was described during oocyte maturation and embryonic development. This study indicates that these two genes in the embryo and ovary perform important roles in reproductive physiology in the oriental river prawn.