Cloning of Lettuce Necrotic Yellows Virus RNA and Identification of Virus-specific Polyadenylated RNAs in Infected Nicotiana glutinosa Leaves

The negative-stranded genomic RNA of lettuce necrotic yellows virus (LNYV) was isolated and estimated by denaturing agarose gel electrophoresis to consist of about 13000 nucleotides (tat). Hybridization of randomly labelled LNYV RNA to poly(A) + RNA from infected Nicotiana glutinosa plants revealed the presence of five distinct complementary RNA species (cRNAs) ranging in size from 900 to 6450 nt. Individual recombinant cDNA clones derived from LNYV RNA hybridized to four of these cRNA species. Each cRNA contained unique sequences which together represented about 95 % of the viral genome. From their size range and sequence complexity, it is assumed that the cRNAs represent messenger RNAs encoding the five LNYV structural proteins. The mRNA for the nucleocapsid protein is cRNA 3 because a recombinant cDNA expression vector clone containing sequences which hybridize to cRNA 3 produced a polypeptide which was detected with a monoclonal antibody specific for the nucleocapsid protein