FIG. 8.

Strategy for sequencing the P1 region of M2 virus and identification of a codon leading to a single amino acid change within the VP1 T-cell epitope region. (A) Schematic presentation of the strategy for sequencing the P1 region of the M2 variant. Arrows indicate the specific primers used in sequencing, and the length represents the size of the sequence analyzed. UTR, untranslated region. (B) M2 virus contains a point mutation (A→G) at nucleotide position 3733 (indicated by the arrow) of VP1 that results in a lysine-to-arginine change at amino acid residue 244 of the VP1 capsid protein. The nucleotide sequences of parent and M2 viruses coding for the VP1₂₄₄ region are shown.