Arsenite and gramicidin D overcome the requirement for ICP0. HFFF2 monolayers were treated with 100 μM sodium arsenite (As) or 12 μg/ml gramicidin D (Gm) for 2 h, washed, and infected with 1 PFU of the ICP0-null mutant dl1403Y (0−) or rescued mutant dl1403YR (R) per cell. At 7 h postinfection, cells were harvested and analyzed for UL42, VP5, and actin protein levels.