The deubiquitination activity of UL36USP is essential for viral DNA replication during HSV-1 infection.
A, HSV-1 C40A mutant virus infection induced ubiquitination of PCNA, whereas wild-type virus exhibited an equivalent level compared with the control group. HEK293T cells were mock infected or infected with HSV-1 wild-type or UL36C40A mutant virus at 0.1 m.o.i. At 16 or 21 h post-infection, cells were fractionated into chromatin-containing fractions by incubating with Triton X-100 buffer. Western blotting was performed using the indicated antibodies. The intensity of ubiquitinated PCNA was normalized to Lamin B. B and C, HSV-1 wild-type virus DNA replication rate is higher than the UL36C40A mutant virus. Vero cells were infected with HSV-1 wild-type or UL36C40A mutant virus. Cells were harvested at the indicated time for quantitative real-time PCR analysis. The quantity of virus DNA was indicated by virus genes tk (B) and vp16 (C), respectively.