FIG. 1.

Viral DNA replication and cleavage are unimpaired in RVΔ140-infected macrophages. (A) Viral DNA replication. IC-21 macrophages were infected with sucrose gradient purified RVΔ140 or revertant virus (WT) at an MOI of 5 or mock infected with an equal volume of uninfected cell supernatant. At 8, 24, and 48 h postinfection, total DNA was harvested. Real-time PCR was performed in triplicate on 1 μg total infected cell DNA using primers specific for MCMV or cellular (IFN-β) DNA. Viral DNA levels were normalized to cellular gene levels. The experiment was repeated three times, and the mean results are shown. Error bars represent standard deviations. (B) Viral DNA cleavage. Two micrograms each of total cell DNA from mock (M)-, revertant virus (WT)-, and RVΔ140 (RV)-infected cells, prepared as described above, were subjected to digestion with MluI, and cleavage was analyzed by Southern blot analysis using a probe (pON4047) that hybridizes to both ends of the cleaved DNA. The experiment was repeated three times, and representative data are shown. The X and C termini are named as such based on EcoRI X and C fragments at the termini of the MCMV genome (22).