FIG 1.

Effects of the 1/2 and/or 2/3 site optimization mutations in the context of the SFV4 genome. (A) Schematic presentation of the parental SFV4 genome and its mutant versions. Mutated upstream (P-side) residues are shown in boldface. (B) Infectivities of in vitro-synthesized virus RNAs, comparative plaque sizes, and pseudoreversions/second-site mutations identified in the genomes of rescued mutant viruses. (C) Graphical presentation of SFV4 nsP2 with regions flanking 1/2 and 2/3 sites. Mutations and compensatory changes affecting P-side residues and the Val 515 residue of nsP2 in the listed constructs are shown in boldface. The infectivity of in vitro-synthesized virus RNAs is shown for each construct. All experiments were repeated at least twice with similar results.