RUNX1-ETO and RUNX1 associated with the RUNX3 P1 promoter. (A) ChIP analysis of the RUNX3 P1 promoter in Kasumi-1 cells using an antibody directed to the N-terminus of RUNX1, ETO, or IgG. Immunoprecipitated chromatin was analyzed by PCR of a 150-bp RUNX3 P1 promoter fragment. (B) ChIP analysis of the RUNX3 P1 promoter in U937 cells, which express RUNX1 but not RUNX1-ETO. (C) ChIP analysis of the RUNX3 P1 promoter in ME-1 cells, which express CBFβ-MYH11. The same antibodies described in panel A were used for immunoprecipitation in panels B and C. Note that no PCR product was obtained when anti-IgG or no antibody was used for immunoprecipitation.