FIG 10.

Impairment of A3 expression does not affect viral replication in vitro. (A and B) Recombineering methodologies used to delete the entire A3 coding sequence by galK insertion and generation of the A3⁻ and A3-rev strains (A) or insert multistop codons at the 5′ end of the A3 coding sequence and generation of the A3ns and A3ns-rev strains (B). The produced BAC plasmids were analyzed by Southern blotting after EcoRI or HindIII restriction and ethidium bromide staining (EtBr). Probes are indicated as follows: A3, entire A3 coding sequence; galK, entire galK coding sequence. (C) Multistep growth curves of WT, A3⁻, A3-rev, A3^ns, or A3^ns-rev virus strains in BT fibroblasts. The data presented are means ± the standard deviations of results from measurements in triplicate. (D) Syncytial areas over time postinfection in MDBK cells. The data presented are means ± the standard deviations of results from syncytium size measurements (n = 25).