Figure 6.

Stabilized UBXN1 suppresses IFN induction. (A) HEK293 cells were transfected with an IFNβ reporter vector together with a vector expressing MDA5 and various amounts of vectors expressing NiV V and UBXN1. The total amount of transfected vector was kept constant by the addition of empty vector. At 24 h posttransfection, a luciferase assay was performed. The values in three data sets, sample No. 1–4, 5–7 and 8–10, were normalized by setting the value of sample No. 2, 5 and 8 to 100% respectively. Samples No. 6, 9 and 7, 10 were statistically compared to No. 3 and 4 respectively. The original data without the normalization were shown in Supplementary Figure S5C. (B) HEK293 cells were transfected with an IFNβ reporter vector together with vectors expressing RIG-IΔ and NiV V with or without a vector expressing UBXN1. The total amount of transfected vector was kept constant by the addition of empty vector. At 24 h posttransfection, a luciferase assay was performed. (C) 293^UBXN1− cells were transfected, and the luciferase reporter assay was performed as described in (B). (D) HA-tagged UBXN1 and myc-tagged NiV V were expressed in HEK293T cells. At 48 h posttransfection, endogenous MAVS was immunoprecipitated with a specific antibody, and the precipitated proteins were detected with western blotting. (E) The model of MAVS interference by NiV V suggested by our results is shown. Error bars indicate standard deviations (N = 3). *P < 0.05, **P < 0.01, *** and ^†††P < 0.001, not significant (n.s.) on Dunnett’s multiple comparison test. The blots presented in (D) were cropped from different images to improve clarity. Full-length blots are presented in Supplementary Figure S4.