Fig. 1: PRMT9 negatively regulates RLRs-induced IFN-β production.

a Immunoblot analysis of PRMT9 in Prmt9-knockout RAW264.7 cell lines. b, c qRT-PCR analysis the expression of Ifnb1, Ifna4 or Cxcl10 mRNA in Prmt9-knockout cells with SeV infection or stimulated with 5′-pppRNA (mean ± SD, two-tailed student’s t test was performed, for b, Ifnb1: *p = 0.0351, **p = 0.0049, **p = 0.0032, *p = 0.0160, *p = 0.0385, *p = 0.0149 in sequence; Ifna4: **p = 0.0020, **p = 0.0029, **p = 0.0026, *p = 0.0104, **p = 0.0067, **p = 0.0030 in sequence; Cxcl10: ****P < 0.0001, **p = 0.0024, *p = 0.0380, **p = 0.0019; **p = 0.0012, *p = 0.0192 in sequence. For c, Ifnb1: ***p = 0.0006, *p  = 0.0341, **p = 0.0023, **p = 0.0022, ****P < 0.0001, **p = 0.0033 in sequence; Ifna4: *p = 0.0155, *p = 0.0175, **p = 0.0081, *p = 0.0382, *p = 0.0199, *p = 0.0117 in sequence; Cxcl10: *P = 0.0246, *p = 0.0195, *p = 0.0212, *p = 0.0332, ***p = 0.0002, **p = 0.0043 in sequence; n = 3 independent experiments). d qRT-PCR analysis of Ifnb1 (left), VSV mRNA (middle) and plaque assay of VSV titers (right) in Prmt9-knockout RAW264.7 cells infected with VSV (MOI (multiplicity of infection), 0.1), and (e) Immunoblot analysis of VSV glycoprotein (VSV-G) in lysates of RAW264.7 cell lines infected with VSV for 0-12 h. For the densitometric analysis (right), VSV bands were normalized with individual actin, line graphs were presented relative to the second lane (mean ± SD, two-tailed student’s t-test was performed, for d, Ifnb1: ***p = 0.0004, **p = 0.0044; VSV mRNA: **p = 0.0052, *p = 0.0144; VSV titier: ***p = 0.0006, 0.0009 in sequence. The data shown in e are from one representative experiment of at least 3 biological independent experiments, two-tailed student’s t-test was performed, for e, **p = 0.0062, *p = 0.0209, **p = 0.0024 in sequence). f Immunoblot analysis of Flag-PRMT9 (left) in contrl HEK293T cells and Flag-PRMT9-overexpressing HEK293T cells. qRT-PCR analysis of IFNB1 mRNA in HEK293T cells transfected for 24 h with those plasmids, followed by infection with SeV. g qRT-PCR analysis of IFNB1 mRNA (left) or VSV mRNA (middle), and plaque assay of VSV titers (right) in HEK293T cells transfected with control plasmid (Ctrl) or plasmid expressing Flag-PRMT9 for 24 h, followed by infection with VSV (mean ± SD, two-tailed student’s t-test was performed, for f, ***p = 0.0008, **p = 0.0016 in sequence; for g: **p = 0.0059, 0.0022, 0.0041 in sequence; n = 3 independent experiments). h Microscopy imaging (left) and Flow cytometry analysis (right) of the replication of GFP-VSV in HEK293T cells transfected with control plasmid (Ctrl) or plasmid expressing Flag-PRMT9 for 24 h, stimulated with VSV-GFP for 18 h, bars: 100 μm. The qRT-PCR results are presented relative to those of untreated wild-type cells or transfected with a Vector plasmid (Average of three replicates, b–d, f, g). The data shown in a, e, f, and h are from one representative experiment of at least 3 biological independent experiments. Two-tailed Student’s t-test was performed, with *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001 (b–g).