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. Author manuscript; available in PMC: 2016 Jul 15.
Published in final edited form as: J Immunol. 2015 Jun 15;195(2):621–631. doi: 10.4049/jimmunol.1401823

Figure 6. IRF4 binds to and transactivates the Il9 and Il1b promoter in mast cells.

Figure 6

Mast cells generated from C57BL/6 (WT) or Il1r1−/− mice were left untreated or stimulated for 48h with ionomycin (Iono, 1μM) in the presence or absence of IL-1β (300pg/ml). IRF4 expression was assessed by western blot analyses (A). Binding of IRF4 to the promoters of Il9 and Il1b was assessed by ChIP-analyses (B). For Il9 and Il1b reporter gene analyses mast cells were transfected with a plasmid coding for IRF4 (+IRF4) or with the corresponding empty vector (+mock) in combination with an Il1b (C) or Il9 (D) promoter-luciferase reporter or promoter-luciferase reporter with mutated IRF4 binding sites and stimulated for 16h with ionomycin (0.5μM). Cell lysates were prepared as outlined in materials and methods section and luminescence was measured. Mast cells transfected with promoter-luciferase vector +mock were arbitrarily set to 1. Panel (A and B) display one representative result from one out of four (A) or three (B) independent experiments. In (C) the mean of three and in (D) the mean of five independent experiments (±SD) is shown. *≤P 0.05; ***≤P 0.001 (two- tailed unpaired t-test). ns= not significant.