Figure 3. Fbxo21 overexpression promotes innate antiviral response, and activates AP-1 and IRF3-IFNβ signaling pathway.
(A) Fbxo21-/- RAW264.7 cells were transfected with Fbxo21 vectors (0, 0.1, 0.2, 0.5 and 1 μg respectively) for 48 hr. Fbxo21 expression was evaluated by immunoblot. (B–E) Cells in (A, transfected with 0, 0.1, 0.2 and 0.5 μg Fbxo21 vectors respectively) were infected with VSV (MOI = 1) or HSV-1 (MOI = 5) for 8 hr. Then indicated cytokines were examined by Q-PCR. β-actin was used as internal control in the Q-PCR assays. (F–I) Cells in (A, transfected with 0, 0.1, 0.2 and 0.5 μg Fbxo21 vectors respectively) were also transfected with indicated reporters and infected with VSV or HSV-1 for 4 hr. Then reporter transactivation was measured by dual-luciferase activity assays. (J–O) Fbxo21+/+ and Fbxo21-/- RAW264.7 cells (J–L) or L929 cells (M–O) were infected with VSV (MOI = 1) or HSV-1 (MOI = 5) for 4 hr. Then nuclear extracts were examined for indicated transcription factors bound to specific DNA sequence by ELISA. Error bars indicated for mean ± SD of triplicate samples. Data were analyzed by one-way ANOVA followed by Bonferroni multiple comparison using PRISM software (ns, not significant; ***p<0.001; versus corresponding Fbxo21+/+ group).