Fig. 1.

Genome organization and secondary structures of PVX. (A) Schematic representation of PVX RNA genome. Single-strand PVX RNA contains five open reading frames (ORFs): RNA-dependent RNA polymerase (RdRp), triple gene block proteins (TGBp1, TGBp2, and TGBp3), and CP. (B) Secondary structure of the positive strand of SL1 RNA as determined by chemical and enzymatic probing (SL1+). The initiation codon of RdRp is indicated by grey circles. Secondary structure of the negative strand of SL1 RNA (SL1−).