Specific TF consensus binding motifs, particularly ETS and eiGATA motifs, are critical for function of heptad regulatory elements. (A) Schematic showing process for selecting TF binding motifs for mutation and luciferase reporter workflow. (B) Conserved TF binding motifs in heptad regulatory elements that were highly bound by heptad TFs in AML cell lines, and activity of wild-type (WT) and mutated luciferase constructs in KG-1 and ME-1 cells (left). Activity is scaled relative to the empty vector, and graphs show representative data from a single transfection experiment. *P < .05; **P < .01; ***P < .001, t test. Heat maps showing aggregate data from all luciferase experiments (right). Data from biological replicates were normalized to WT activity for each experiment, then aggregate data scaled relative to empty vector. Heat maps are scaled from 0 to maximum luciferase activity for each regulatory element. (C) Schematics showing conserved TF binding motifs in heptad regulatory elements that were highly bound by heptad TFs in AML cell lines, and activity of WT luciferase constructs in KG-1 and ME-1 cells. Activity is scaled relative to the empty vector, and graphs show representative data from a single transfection experiment. *P < .05; **P < .01; ***P < .001 (Student t test).