Fig. 3: VSV infection induces METTL3 cytoplasmic translocation and dampens type I IFNs.

a Western blot analysis of Mettl3 protein along VSV infection of RAW264.7 cells. The upper graph indicates statistic result. b Cellular fractionation and Western blot analysis of METTL3 protein localization before or post VSV infection in HEK293T cells. c Immunofluorescence analysis of endogenous METTL3 protein subcellular localization before or post VSV infection for 6 h in HeLa cells. d Immunofluorescence analysis of endogenous METTL3 protein subcellular localization before or post HBV (DNA virus) infection as indicated timepoints in AC12 cells. e The domain organization and dissection of the human METTL3 protein. NLS-mut: nuclear localization signal-mutation. f Immunofluorescence analysis of METTL3 protein subcellular localization after NLS-mutation in HeLa cells. g Dot blot analysis of mRNA-m⁶A level after overexpression of NLS-mut or WT METTL3 in HeLa cells. Methylene blue staining indicated the loading control. h qRT-PCR analysis of IFNB1 expression following a 12 h treatment with PBS or VSV infection before transfection of Vector/ NLS-mut/ WT METTL3, respectively, in HeLa cells. i IFN-β promoter activity in HEK293T cells transfected with METTL3 vectors upon VSV infection. j RAW264.7 cells overexpressed catalytic-mutated Mettl3 (Mettl3-mut) or WT Mettl3 in mock (PBS) or VSV infection for 12 h. The supernatants were collected to perform plaque assay, which indicated the VSV titer. k, l qRT-PCR and ELISA analysis of Ifnb1 expression in RAW264.7 cells overexpressed Mettl3-mut or WT Mettl3 in mock (PBS) or VSV infection for 12 h. Data are representative of 3 independent experiments. *p < 0.05, **p < 0.01, ***p < 0.001, as determined by two-tailed unpaired Student’s t test. Error bars represent mean ± SEM.