Mutation of Thr75 or addition of p38 MAP kinase inhibitors affects the transactivation ability of C/EBPϵ on a myeloid-specific promoter. Jurkat cells were transfected with the C/EBPϵ constructs and the mim promoter in a luciferase vector. The cells were harvested 48 hours after transfection and luciferase (LUC) and β-galactosidase activities were measured. These results are shown as relative luciferase units (RLUs) representing the mean of 3 experiments.