Immunoblots of mutant viruses. Purified virions (left panels) or lysates of RK13 cells (right panels) infected with PrV-Ka, PrV-ΔUL51F, PrV-ΔUL51FR, or PrV-ΔUL51F/11G were separated by electrophoresis in sodium dodecyl sulfate gels containing 10% (for detection of gH, UL37, and UL49 proteins) or 15% (for detection of the UL51 and UL11 proteins) polyacrylamide. After transfer to nitrocellulose filters, blots were probed with monospecific sera against UL51N, UL51C, UL11, UL37, UL49, and gH. Locations of molecular mass markers are indicated to the left of each panel.