Activity of viruses with Tcf sites in the E1B and E2 promoters. (A) Western blot showing DBP and E1B 55K expression 24 h after infection of SW480, H1299, and WI38 with the indicated viruses. (B) E1B exon structure showing the position of the RT-PCR primers and Taqman probe. (C) PCR quantitation of adenoviral E1B and E2 mRNA (upper two panels) and adenoviral genomic DNA (lower panel) 24 h after infection of SW480 and H1299 with the indicated viruses. (D) Burst assay for virus production by SW480, H1299, and WI38 48 h after infection with the indicated viruses. The viral titer was measured by plaque assay on SW480.