FIG 4.

gI is only required for UL24syn. (A) Cells were infected with gI deletion mutants, harvested 18 hpi, and the lysates analyzed for VP5, gE, and gI expression via immunoblotting. The blots are arranged according to the type of Syn variant. (B) Vero cells were infected with the indicated mutants at a low MOI. At 36 hpi, they were fixed and stained with DAPI and antibodies specific for VP5. Corresponding bright-field and fluorescent images were taken for each variant. (C) For each of the indicated mutants, the areas of 30 individual syncytia were measured at 36 hpi. The reduced average areas of the mutants relative to their Syn parent are plotted. P values were calculated by the Student's t test. *, P < 0.05; **, P < 0.01; ****, P < 0.0001. Additionally, each site of infection was also scored as syncytial, mixed, or lytic (as defined in the text), with the linear distribution of these phenotypes shown graphically.