Molecular analysis of Fiji Disease Fijivirus genome segments 1 and 3

Fiji disease fijivirus (FDV) genomic segments 1 (S1) and 3 (S3) were completely sequenced. FDV S1 comprised 4532thinspnt and was predicted to encode a 170.6thinspkDa protein. FDV S3 comprised 3623thinspnt and was predicted to encode a 135.5thinspkDa protein. The terminal sequences of S1 and S3 were 5prime AAGUUUUU......CAGCUAGCGUC 3prime and 5prime AAGUUUUU......CAGCAGAUGUC 3prime, respectively, and located immediately adjacent to these sequences were 12thinspbp imperfect inverted repeats. The predicted translation product of FDV S1 showed highest similarity to Rice black-streaked dwarf virus (RBSDV) S1 and is thought to encode the viral RNA-dependent RNA polymerase (RdRp). The predicted translation product of FDV S3 was found to be most similar to RBSDV S4 which is thought to encode the 'B-spike' protein. The FDV sequence contained an ATP/GTP binding motif and a leucine zipper motif, but these motifs were not found in the RBSDV sequence. Phylogenetic analysis based on the amino acid sequences of the RdRp of FDV S1 and other reoviruses revealed that the fijiviruses form a cluster close to the oryzaviruses. The RdRp sequences were grouped into genera that were consistent with the current reovirus classification scheme that is based on physico-chemical and biological properties