抄録
In birnaviruses, the viral capsid proteins VP2 and VPS, and the protease NS are translated as a polyprotein. In this study, the complete polyprotein gene was sequenced and the deduced amino acid sequence was analyzed for the marine birnavirus (MABV) strain Y-6. Comparison of VP2 region with infectious pancreatic necrosis virus (IPNV) strains revealed that the central part of VP2 contained a variable region whereas the N- and C-terminal parts appeared conserved among the MABV and IPNV strains. In the VPS gene, hydrophilic residues were concentrated around the C-terminal region, suggesting that this region was exposed to the outside of the molecule. The N-terminal of NS appeared variable, however, the C-terminal appeared conserved. This result was similar to previous reports of other IPNV strains. The VPS open reading frame (ORF) was found in 5'-end of the plyprotein ORF. Considerable variation was found in this region compared to other proteins. The amino acid composition of VPS indicated a high, rich concentration of arginine suggesting that VP5 is a basic protein that may function in RNA binding. This is the first report of the complete analysis of the MABV polyprotein gene.
