FIG. 2.

Deletion of vhs and ICP0 results in sustained ISG56 mRNA accumulation. (A) Construction of a double mutant virus deleted for vhs and ICP0. U2OS cells were coinfected with Δsma and 7134 to create a double mutant virus as outlined in Materials and Methods. (Left panel) PCR analysis was used to confirm the internal SmaI-SmaI fragment deletion that defines the vhs Δsma mutation. BstEII-cut lambda DNA was used as a marker. (Right panel) Southern blot analysis with a radiolabeled ICP0 probe was used to distinguish wild-type ICP0 and 7134 ICP0 sequences based on the presence of a unique SstI site within the lacZ gene that replaces the ICP0 sequence in the 7134 mutation. (B) RT-PCR analysis of total RNA harvested from HEL fibroblasts at various times postinfection with the indicated viruses. GAPDH, glyceraldehyde-3-phosphate dehydrogenase.