FIG. 6.

The loss of tyrosine phosphorylation does not affect the subcellular localization of VP22 or mutant virus replication in vitro. MDBK cells were infected at an MOI of 0.01 with BHV-1 (A) or vYNull (B) for 18 h and then fixed with 4% paraformaldehyde, labeled with anti-VP22 antibody, and analyzed by indirect immunofluorescence microscopy. Both forms of VP22 localized in cell nuclei. (C) Levels of virus growth in vitro were compared using a single-step growth curve. The dephosphorylation of VP22 resulted in only a slight decrease of virus titer.