Figure 4: Cell type-specific expression of Il1b and Il21 genes correlates with the differential STAT3 binding and enhancer landscapes.

(a) Freshly isolated cDCs were rested 1 h, then stimulated with IL-21 for 4 h; CD4⁺ T cells were pre-activated for 3 days, then washed and rested 16 h, and stimulated with IL-21 for 4 h. Shown are genes differentially regulated by IL-21 in cDCs versus pre-activated CD4⁺ T cells. For cDCs, gene expression profiling was performed by microarray analysis, where cDCs were pooled from three independent experiments, as described in ref. 16. For pre-activated CD4⁺ T cells, gene expression profiling data were generated by RNA-Seq analysis. Shown are data from one of two similar experiments. (b) Il1b and Il21 expression in cDCs and CD4⁺ T cells not treated or stimulated with IL-21 as in a. Data are representative of 3 experiments. Error bars are technical duplicates of the representative experiment. (c,d) STAT3 binding, H3K4me1, H3K27ac, H3K4me3, and H3K27me3 marks at the Il1b locus in cDCs (c) and CD4⁺ T cells (d). Arrows in c indicate STAT3 binding sites at GAS1, GAS2 and GAS3 regions (GAS1: TTAgggGAA (−155 bp), TACcctGAA (−175 bp), TCCctgGAA (−195 bp); GAS2: TTTgggGAA (−2,452 bp), TTCctcCAA (−2,525 bp), TTCttcAAA (−2,549 bp); GAS3: TTGtgtGAA (−9,761 bp)). Arrows in d indicate the STAT3 binding sites identified in cDCs, but no STAT3 binding was seen at these sites in CD4⁺ T cells. (e,f) STAT3 binding, H3K4me1, H3K27ac, H3K4me3 and H3K27me3 marks at the Il21 gene locus in cDCs (e) and CD4⁺ T cells (f). Arrow in f indicates the STAT3 binding site at the GAS motif in the Il21 promoter region. Arrow in e indicates this same site, but no STAT3 binding was seen at this site in cDCs. Data are representative of two experiments. Statistical analysis was performed by Student’s t-test.