Fig. 3: FLI1 upregulates CBP to increase promoter accessibility of IDO1.

A The chromatin accessibility at the IDO1 promoter in FLI1-KO and WT HK1 cells was measured by ATAC-seq. Cells were treated with IFN-γ for 24 h. B CBP and KAT5 protein levels in FLI1-KO and WT HK1 and NPC43 cells were detected by western blot. C, D IDO1 mRNA (C) and protein (D) levels in CBP-knockdown and control HK1 and NPC43 cells were detected. E Kyn level in the culture supernatants of CBP-knockdown and control HK1 and NPC43 cells was measured. F Representation of Flag-FLI1 ChIP-seq and input profiles at the CBP gene locus. HK1 cells overexpressing Flag-FLI1 were treated with or without IFN-γ. G ChIP-qPCR analysis was performed with an antibody to Flag and CBP-promoter-specific primers in HK1 and NPC43 cells overexpressing Flag-FLI1. Cells were treated with IFN-γ for 24 h. H FLI1-KO and WT HK1 and NPC43 cells were transfected with a CBP promoter-luciferase reporter PGL4 plasmid for 24 h. Cells were then treated with IFN-γ for another 24 h, followed by analysis of luciferase activity. I ChIP-qPCR analysis was conducted with an antibody to Flag and IDO1-promoter-specific primers in HK1 and NPC43 cells overexpressing Flag-CBP, following IFN-γ treatment for 24 h. J ChIP-qPCR analysis was carried out with the indicated antibodies (H3K9Ac, H3K14Ac, H3K18Ac and H3K27Ac) and IDO1-promoter-specific primers in HK1 and NPC43 cells, with or without IFN-γ treatment. K ChIP-qPCR analysis was performed with the indicated antibodies (H3K9Ac and H3K27Ac) and IDO1-promoter-specific primers in the indicated NPC cells upon IFN-γ stimulation. L, M IDO1 mRNA (L) and protein (M) levels in the indicated NPC cells with or without IFN-γ treatment were measured. N Kyn production in the culture supernatants of the indicated NPC cells was analyzed. The results are representative of three independent experiments (B–E, G–N). The data are presented as the mean ± SD (C, E, G–L, N). Statistical analysis was performed by one-way ANOVA with Tukey multiple comparisons test (C, E, H, K, L, N) and two-tailed unpaired t test (G, I, J). Source data are provided as a Source Data file.