The changes in viral gene expression resulting from incubation with ganciclovir or PFA in the absence and presence of valproate. BCBL-1 cells were incubated in the absence or presence of valproate (0.6 mM) in medium that contained the indicated concentration of ganciclovir or PFA (μM). After a 4-day incubation, total cellular RNA was isolated, and 20 μg RNA of each sample was size fractionated and analyzed by Northern blot analysis for the indicated transcripts. The nitrocellulose was stripped with boiling water prior to each hybridization.