FIG 4.

Effect of pUL50 expression on UBE1L level induced by IFN-β treatment or viral infection. (A) HF cells were mock infected or infected with UV-HCMV or HCMV (Toledo strain) at an MOI of 3 for 24 or 48 h. The levels of the UBE1L, IE1/IE2, and pUL50 proteins were determined by immunoblotting. Bands indicating pUL50 and its 26-kDa isoform (UL50-p26) are indicated with arrowheads. Levels of β-actin are shown as a loading control. (B) Control and pUL50-HA-expressing HF cells produced by retroviral vectors (MIN) were left untreated or treated with IFN-β (1,000 U/ml) for 48 h and then incubated with or without cycloheximide (CHX; 100 μg/ml) for the indicated times. The levels of UBE1L, pUL50-HA, and β-actin were detected by immunoblotting. The relative levels of UBE1L (normalized to levels of β-actin) are shown in the graph. (C) HF cells were mock infected or infected with recombinant adenoviruses (Ad-lacZ or Ad-UL50-HA) at an MOI of 5 for 24 h and then superinfected with UV-HCMV (Toledo) for 24 h. The levels of UBE1L, pUL50-HA, and β-actin were determined by immunoblotting.