Structure of the UL50-UL51 locus in vCAG, vLAT, vHS4-L, and vUCOE2 (A) and relative UL50 (B) and UL51 (C) mRNA levels in infected HDFs. The data are means and SD; *, P ≤ 0.05; ***, P ≤ 0.001; ****, P ≤ 0.0001 compared to vCAG at the same time point (2-way ANOVA).