Fig. 4.

Reverting mutations arising in TGEV chimeric S proteins. (A) Plaque assay of the original TGEV S protein Endo recombinants (Mut-TGEV and Mut-MMT) and their corresponding purified revertants (TGEV-R1, TGEV-R2, MMT-R1, and MMT-R2); wild-type (WT) and Mut-30 viruses served as positive and negative controls, respectively. (B) Alignment of mutated Endo sequences of revertants compared to their parents and controls; the newly generated heptapeptide terminus of TGEV-R1 and MMT-R1 is underlined.