Western blot analyses. Extracts of RK13 or RK13-UL37 cells infected with PrV-Ka, PrV-UL35GFP, PrV-ΔUL37, and PrV-ΔUL37/GFP were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and proteins were transferred to nitrocellulose filters. Blots were incubated with monospecific rabbit antisera against pUL37 and pUL35 at dilutions of 1:100,000. Binding of peroxidase-conjugated anti-rabbit antibodies (Dianova) were detected by chemiluminescence (SuperSignal; Thermo Scientific). Locations of molecular mass marker proteins are indicated.