Southern blot analysis of genomic DNA from HeLaEBNA1 cells transduced with the indicated substrate vectors at early time points posttransduction (a) and at late time points posttransduction (b). −FLPe, no cotransduction with HC-AdFLPe; +FLPe, cotransduction with HC-AdFLPe. Circular substrate vector genomes are represented by signals at 2,200 bp; linear substrate vector genomes are represented by signals at 3,300 bp. Ctr, DNA from untransduced control cells.