Fig. 4: SAMD9 OB-fold domain is essential for IFN induction.

A Schematic representation of SAMD9. FL full-length, OB oligonucleotide binding-fold domain. B Validation of WT HT-29 and SAMD9 KO HT-29 cells complemented with Ev, SAMD9-mGFP (FL), SAMD9-∆OB-mGFP (∆OB) by western blot with indicated antibodies. C WT HT-29 and SAMD9 KO HT-29 cells complemented with Ev, FL, or ∆OB transfected with poly(dA:dT) (1 μg/ml) for 24 h and the IFNL3 mRNA level measured by qRT-PCR. D WT HT-29 and SAMD9 KO HT-29 cells complemented with Ev, FL, or ∆OB transfected with LMW poly(I:C) (1 μg/ml) for 24 h and the IFNL3 mRNA level measured by qRT-PCR. E EMSA of His-MBP-tagged SAMD9 FL or ∆OB proteins with circular dsDNA. F Immunoblotting analysis of streptavidin immunoprecipitates of cell lysates from WT HT-29 and SAMD9 KO HT-29 cells complemented with FL or ∆OB incubated with biotinylated 48,502-bp dsDNA. G Immunoblotting analysis of anti-Flag antibody immunoprecipitates of cell lysates from HEK293 cells transfected with Myc-DDK-tagged SAMD9 FL or ∆OB. H WT HT-29 and SAMD9 KO HT-29 cells complemented with FL or ∆OB transfected with poly(dA:dT) (10 μg/ml) for 8 h, and cell lysates harvested for native-PAGE or SDS-PAGE electrophoresis with indicated antibodies. For all figures, experiments were repeated at least three times. Individual points in (C and D) represent independent experiments. Data are represented as mean ± SEM. Statistical significance in (C and D) calculated by one-way ANOVA with Tukey’s post-test: ***P < 0.001. Source data are provided as a Source Data file. Detailed P-values are provided in the Source Data file.