Substitutions found in FMDV mutants that encode one VPg, upon passage in BHK–21 cells a.

aThe consensus sequence of the entire viral genome was determined for FMDV populations V3, V19–4 and V15–9 (series A and B) after 2 passages in cell culture (experiment described in Figure 3). The sequence of viral genomic regions 2C, 3A, 3B (VPg), 3C and 3D (residues from genomic position 4200 to 8115) was determined for 5 independent biological clones isolated from population V3A at passage 1. The origin of each population is described in the text and in Figure 3.bFMDV genomic region analysed [15].cMutations and deduced amino acid substitutions are relative to the sequence of the parental clone FMDV WT (pMT28, described in Materials and Methods); residue numbering is according to [49]. Amino acid residues (single–letter code) are numbered individually for each protein from the N– to the C–terminus. Procedures for nucleotide sequencing and identification of FMDV genomic regions are described in Materials and Methods.dPopulations and biological clones in which the substitutions indicated in c were found.eMutation C4507U (that corresponds to amino acid substitution R55W in 2C) was repeatedly found in 3 out of 6 mutant FMDV populations at passage 2, and 2 out of 5 biological clones from population V3A at passage 1 (underlined).