Genomic sequence analyses of segments 1 to 6 of Dendrolimus punctatus cytoplasmic polyhedrosis virus

The complete nucleotide sequences of genomic segments S1 to S6 from Dendrolimus punctatus cypovirus 1 (DpCPV-1) have been determined. Each segment of S1 to S6 possess a single open reading frame. Conserved motifs 5' (AGUAA) and 3'(GUUAGCC) were found at the ends of each segment. Comparison of the proteins of DpCPV with those of other members in the family Reoviridae lead us to suggest that S1, S3, S4 and S6 encode the viral structural protein VP1, VP2, VP3 and VP4, respectively. S5 encoded viral non-structural protein p100 and S2 encodes an RNA-dependent RNA polymerase (RdRp). Motif analysis shows that VP3 is similar to the methyltransferase of Methanosarcina mazei Goe1, VP4 has motifs for leucine zipper and ATP/GTP-binding sites, and p100 is remarkably similar to foot-and-mouth disease virus 2A protease (FMDV 2Apro). Phylogenetic analysis of RdRps from nine viruses of the family Reoviridae indicates that DpCPV is a type 1 cypovirus, more related to Bombyx mori cypovirus (BmCPV) than to other cypovirus species. DpCPV is more related to Rice ragged stunt virus (RRSV) than to other members of different genera of the family Reoviridae, which seems to confirm the previous hypothesis that plant reoviruses originated from insect reoviruses.