Transactivation of the M-CSF receptor promoter by exogenously expressed RUNX1 proteins.

(A) Cells were transfected with a luciferase reporter plasmid and the indicated RUNX1 expression constructs. Luciferase activities were measured and presented as the fold increase relative to the control transfected with the backbone expression vector. (B) The wild-type RUNX1 and missense RUNX1 mutants were coexpressed in varying doses as indicated. Luciferase activities are expressed as fold changes relative to the activity observed at the standard dose (0.3 μg) of the wild-type RUNX1 alone. (C) PEBP2β/CBFβ was transfected in varying doses with a repressive dose of wild-type and mutant RUNX1 proteins. In panels A-C, each value represents the mean of 3 separate experiments. The luciferase activity of the y-axis in panel C is shown as relative luciferase units (RLU). Deviations of the measurements are given by thin vertical bars. The chimeric protein PEBP2β/CBFβ-MYH11 and the sporadic mutation K83N were used as controls in each experiment. All examples in this figure are in U937 cells.