IFN inhibition of replication is conserved among different Ad serotypes.
(A) Nucleotide sequence alignment of the E1A enhancer regions from different Ad subgroups (serotypes Ad5, Ad3, Ad4, Ad9 and Ad12 corresponding to Ad subgroups C, B, E, D and A, respectively). Homologies (≥75% identity) are shaded in blue. The GABP and E2F binding sites, as well packaging repeats (arrowhead A1-5), are indicated. (B) HDF-TERT cells were treated with IFNs or left untreated for 24 hr and then infected with 25 virus particles/cell Ad5, Ad3, Ad4, or Ad12 or 5 virus particles/cell Ad9. Nuclear DNA was isolated at 6 hr post-infection to determine virus input and at 72 hr post-infection with Ad3, Ad4, Ad9 and Ad12 or at 48 hr post-infection with Ad5 to measure replication. Viral DNA levels were quantified by qPCR using a primer that recognizes conserved sequence in E1A (AdE1A-Pan) in combination with a serotype-specific primer (S1 Table in S1 Materials and Methods). The values were normalized to 1.0 in untreated cells and are plotted as mean ± sd, n = 3.