Detection of Polyadenylated Subgenomic RNAs in Leaves Infected with the Potexvirus Daphne Virus X

Abstract

The genomic RNA (6.0 kb) and five subgenomic RNAs of 4.9, 4.0, 2.1, 1.4 and 0.8 kb were detected by Northern hybridization in leaves of Nicotiana clevelandii infected with daphne virus X (DVX). Also, five species of dsRNA specific to DVX were extracted from infected leaves. In denaturing gels the dsRNAs gave bands with mobilities similar to those of the genomic RNA and the 4.9, 4.0, 2.1 and 0.8 kb subgenomic RNAs. The single-stranded RNAs apparently contain a tract of poly(A) as shown by oligo(dT)-celluloe chromatography and by an increased mobility on agarose gels following digestion with RNase H in the presence of oligo(dT)12-18. When added to reticulocyte lysate, DVX RNA directed the synthesis of a 160,000 mol. wt. (160 K) protein and several smaller proteins. The coat protein (26K) was identified by immunoprecipitation with antiserum to DVX particles among the translation products of poly(A)-containing RNA isolated from infected leaves. This protein (26K) was translated from the smallest subgenomic RNA (0.8 kb) but was not translated from full-length DVX RNA isolated by centrifugation through formamide-sucrose gradients.