FIG 1.

Generation of promoter-swapped viruses with altered kinetics of expression for F13 and A26. (A) Recombinant viruses in which the promoter of the F13 gene (blue) and the promoter of the A26 gene (red) were swapped. (B) Genomic organization of the A26 and F13 loci in each of the engineered viruses. The genetic identity of the promoters introduced in the promoter-swapped recombinant viruses was verified by restriction enzyme digestion of PCR amplicons produced with oligonucleotides flanking the promoters (indicated by arrows). Size of the amplicons and the expected digested fragments are indicated. (C) Digestion of viral genome PCR amplicons with the indicated restriction enzymes. All viruses yielded the expected restriction pattern according to their promoter configuration and as observed from digestion of plasmid amplicons obtained from transfer vectors.