Fig. 6: oHSV-1 induces SUV39H2 degradation via the ubiquitin-proteasome pathway in an ICP0-dependent manner.

A SCC15 cells were infected with oHSV-1 at increasing multiplicities of infection (MOI, 0.01–1). Western blot analysis was performed to assess SUV39H2 protein levels at 12 and 24 h post-infection (hpi). Tubulin was used as a loading control. B SCC15 cells were transfected with increasing amounts of His-ICP0 plasmid (100–500 ng) for 48 h. Western blot analysis revealed a dose-dependent decrease in endogenous SUV39H2 protein levels. Tubulin was used as a loading control. C HEK293T cells were co-transfected with 3HA-SUV39H2 and increasing amounts of His-ICP0 (100–500 ng). Western blot analysis demonstrated a dose-dependent reduction in 3HA-SUV39H2 protein levels. GAPDH was used as a loading control. D SCC15 cells were transfected with His-ICP0 (500 ng) for 40 h, followed by treatment with MG132 (10 μM, proteasome inhibitor) or chloroquine (CQ, 50 μM, lysosomal inhibitor) for 3 h. Western blot analysis showed that MG132 restored SUV39H2 levels, while CQ had no effect, indicating that ICP0 promotes SUV39H2 degradation via the ubiquitin-proteasome pathway. β-Tubulin was used as a loading control.