Protein expression of PrV-ΔUL31Pass and PrV-ΔUL34Pass mutants. RK13 cells were infected with wild-type PrV-Ka (lane 2), PrV-ΔUL46gfp (lane 3), PrV-ΔUL46w (lane 4), PrV-ΔUL31Pass (lane 5), PrV-ΔUL31Pass/ΔUL46gfp (lane 6), PrV-ΔUL31Pass/ΔUL46w (lane 7), PrV-ΔUL31Pass/UL46wt (lane 8), PrV-ΔUL34Pass (lane 9), PrV-ΔUL34Pass/ΔUL46gfp (lane 10), PrV-ΔUL34Pass/ΔUL46w (lane 11), and PrV-ΔUL34Pass/UL46wt (lane 12) at an MOI of 3 or were left uninfected (lane 1). At 18 h postinfection, cell lysates were harvested, separated on SDS-polyacryamide gels (10 or 12%), blotted, and incubated with antisera as indicated on the right. Molecular masses (in kDa) of marker proteins are indicated on the left.