Properties and in vitro Translation of Maize Dwarf Mosaic Virus RNA

Abstract

SUMMARY The RNA of maize dwarf mosaic virus strain A (MDMV-A) was characterized and compared with that of strain B (MDMV-B). Glyoxal-treated MDMV-A RNA has an M r of 3·32 × 106 measured in agarose gels, compared with that of MDMV-B which is 3·41 × 106 under the same conditions. MDMV-A RNA has a Tm of 50·7 °C and a hyperchromicity of 23·3%, which are higher than those reported for MDMV-B RNA. Translation products of both RNAs in a rabbit reticulocyte cell-free system ranged from 23K to 121K. Four major polypeptide products of 57K, 91K, 100K and 117K were produced by MDMV-A RNA-directed translation, and four major products of 39K, 55K, 86K and 121K by MDMV-B RNA. Protein profiles from the two RNAs were distinct including translation products that comigrated with authentic coat protein at 37K (MDMV-A) or 39K (MDMV-B) for each strain. Anti-virion sera immunoprecipitated polypeptide products from each strain. Distinct subsets of translation products were immunoprecipitated with antisera to tobacco etch virus 49K and 54K nuclear inclusion proteins. No cell-free translation products were recognized by antisera to potato virus Y (PVY) or tobacco vein mottling virus (TVMV) helper components or antisera to the cylindrical inclusion proteins of PVY or TVMV.