Fig 3.
Potential suppressor mutation-induced base pairings in progeny of the B142–173/M chimera. (A) Summary of potential suppressor mutations and their positions within the inter-stem-loop and downstream partnering domains that appeared in the small and large plaque isolates after 10 serial passages (depicted as in Fig. 1C). (Top) Base positions (in parentheses) for the BCoV sequence (lowercase) use BCoV numbering. Base positions elsewhere use MHV numbering. (Bottom) Summary of base changes at the named positions. The subscript numbers indicate the number of occurrences in 17 total isolates, shown in Table 1. (B) Three potential folding patterns as suggested by Mfold that together maximize the base pairings enabled by the suppressor mutations. Any of the three potential foldings can accommodate revertants S2, L2, L3, L5, L6, L7, L8, and L11, and others are accommodated as indicated. For revertants depicted in Table 1, base pairings within the base-pairing window at passage 10 increased from 19 to 22, 23, 24, or 25 (as summarized in the last two columns of Table 1).