Cloning and Expression of a ML Superfamily Protein in Marsupenaeus japonicas

Key words: 
• Marsupenaeus japonicus /
• MD-2-related lipid-recognition superfamily /
• white spot syndrome virus（WSSV） /
• shrimp larvae

Abstract: MD-2-related lipid-recognition（ ML） superfamily proteins have a single ML domain,which can be bound to specific lipids and play important roles in innate immunity,lipid-recognition and metabolism. The cDNA and gene of a ML protein was identified form Marsupenaeus japonicus,and this ML protein was named as MjML. The full length cDNA of the MjML was 614 bp,with a 453 bp open reading frame that encoded 150 amino acid residues. The MjML gene was 1678 bp in length,and consisted of four exons and three introns. The putative MjML protein contained 6 cysteines which could form 3 pairs of disulfide bonds. Real-time quantitative PCR results showed that MjML mRNA was mainly highly expressed in the hepatopancreas,but very low in other examined tissues. After V. parahaemolyticus was challenged with white spot syndrome virus（ WSSV）,the expression of MjML in hepatopancreas increased gradually and then decreased. At 24 h,the MjML was upregulated and its expression reached the peak. During the early larval development of V. parahaemolyticus,especially after the metamorphosis,the MjML expression had a sharp rise. The MjML expression increased step by step at the post-larvae stage. The results showed that the MjML might play a role in the innate immunity of V. parahaemolyticus. And during the early larval development,the expression of MjML mRNA there might be correlated with the molting and metamorphosis in shrimp larval development.