a, TRIM43 protein expression in primary HFF cells that were either mock-infected, or infected with live HSV-1 or UV-inactivated HSV-1 (HSV-1 UV) (both MOI 1) for 16 h, determined by IF using an anti-TRIM43 antibody. DAPI, nuclei (blue). Scale bar, 20 μm. b, TRIM43 and DUX4 transcripts in HFF cells infected with HSV-1 (MOI 1) for the indicated times, determined by qRT-PCR. Values are presented as fold induction (normalized to 18S rRNA) relative to uninfected control cells (0 h). c, Endogenous DUX4 protein expression in HFF cells that were infected with HSV-1 (MOI 5) or VSV-GFP (MOI 0.05) for 18 h, or that remained uninfected (mock), determined by immunoblot (IB) analysis using anti-DUX4 antibody. IB of HSV-1 infected cell protein 8 (ICP-8) and GFP (VSV-GFP) served as controls. d, DUX4 transcripts in Huh7 cells infected with VSV-GFP (MOI 0.05), HSV-1 (MOI 5), or DV (MOI 1) for 18 h, assessed by qRT-PCR. Values were normalized and calculated as in (b). e, TRIM43 transcripts in HEK 293T cells transfected with empty vector or a plasmid encoding human DUX4, determined by qRT-PCR at 36 h post-transfection. f, Upper: TRIM43 transcripts in HFF cells that were transfected with non-targeting control siRNA (si.C) or DUX4-specific siRNA (si.DUX4) for 24 h and subsequently infected with HSV-1 (MOI 0.1) or VSVGFP (MOI 0.05) for 14 h, assessed by qRT-PCR. Values were normalized and calculated as in (b). Lower panel: Knockdown of endogenous DUX4 was confirmed by IB with an anti-DUX4 antibody. IB of ICP-8 (HSV-1) and GFP (VSV-GFP) served as infection controls. g, RNAseq of HEK 293T cells that were either mock-treated, transfected with a plasmid encoding human DUX4 for 18 h, or infected with HSV-1 (MOI 10) for 18 h. Scatter blot of global gene expression in DUX4-expressing vs. HSV-1-infected cells, relative to mock-treated cells, is shown. Data represent mean and s.d. of n = 3 (biological replicates) (b, d–f). Data are representative of three (a–f) or two (g) independent experiments.