MxA mediates SUMO-induced VSV resistance. (A) Nontargeting control shRNA (Ctrl) and shRNA targeting MxA stably expressed in HeLa-wt, HeLa-SUMO1 (HeLa-S1) and HeLa-SUMO3 (HeLa-S3) cells were infected with VSV at an MOI of 1 for 8 h. Twenty micrograms of protein extracts from infected cells was analyzed by Western blotting for VSV proteins, MxA, and actin. (B) Immunofluorescence using rabbit anti-MxA antibodies was carried out with HeLa-wt, HeLa-SUMO1, and HeLa-SUMO3 cells stably expressing control shRNA and shMxA. (C) The knockdown of IFN-induced MxA by shRNA in HeLa-wt cells is shown using mouse monoclonal anti-MxA antibody (which does not recognize endogenous MxA). (D) The supernatants from infected cells were used to determine virus yields. Mean values and standard deviations from three independent experiments are shown.