FIG. 7.

Formation of ICP4 foci is dependent on correct folding of its DNA binding domain. Vero cells were infected with virus vEYFP-ICP4tsK (MOI = 10) at either the permissive or nonpermissive temperature (33 and 38.5°C, respectively). (A and B) At 38.5°C, the protein gave a diffuse nuclear distribution (A; 6 h postinfection) in contrast to the appearance at 33°C of nuclear foci that were similar to those in a wild-type virus infection (B; 4 h postinfection) (compare with Fig. 2). (C) Cells that had been held at nonpermissive temperature for 6 h and then shifted down to the permissive temperature exhibited a rapid appearance of ICP4 foci. (D) The same cell 15 min after temperature downshift.