FIG. 4.

ICP0 is not required for phosphorylation and stabilization of p53 during HSV-1 infection. HFFF-2 cells were either mock infected or infected with HSV-1 (strain 17+) and the indicated mutants. (A) The mutants used were HSV-1 IE-1 mutants that expressed no ICP0 (dl1403/ΔICP0) or had a deletion in the RING finger domain of ICP0 (FXE) and two ICP0 USP7-negative binding mutants, M1 (a substitution mutant carrying the mutations 623R to L and 624K to I in ICP0) and D12 (a deletion mutant lacking amino acids 594 to 633 of ICP0). These mutants were used at an MOI of 1 PFU/cell. (B) The mutant used was dl1403 (ΔICP0), which was added at various MOIs (as indicated). At 8 h p.i., the cells were either harvested or treated with CHX, as designated (final concentration, 10 μg/ml), for an additional 10 h before being harvested. The cell extracts were then analyzed by Western blotting with anti-ICP0, -ICP4, -p53, and -actin monoclonal antibodies and a phospho-specific p53-Ser15 rabbit polyclonal antibody.