In vitro translation of rice dwarf phytoreovirus genome segments S4 to S10.

The individual synthetic plus-strand transcripts from full-length cDNAs of rice dwarf phytoreovirus genome segments S4 to S10 directed the in vitro synthesis of predominant polypeptides, whose migration positions in SDS-polyacrylamide gel indicated molecular masses of 83 k (P4), 89 k (P5), 56 k (P6), 58 k (P7), 43 k (P8), 49 k (P9), and 35 k (P10), respectively. P7 and P8 had the same mobilities as those of the structural proteins, supporting the previous observations. The other proteins (P4, P6, P10) as well as P9, which had been considered an outer capsid protein, are probably nonstructural proteins, since no polypeptides with similar migration behavior were found in a purified RDV preparation. It remains to be confirmed biochemically whether S5 encodes the outer layer protein.