Schematic diagram of the structure of human hemoglobin reporter constructs and EKLF, GATA1, and EKLF-GATA1 fusion constructs. (A) Comparison of the δ- and β-globin promoter proximal regions; GATA1- and EKLF-binding sites are indicated. (B) The β-globin locus on human chromosome 11. Schematic diagram of δ-, β-, and γ-globin promoter regions in a luciferase reporter construct with the known functional EKLF- or GATA1-binding sites in each promoter indicated.^18,19,24-27  (C) Schematic diagram of the structure of EKLF, GATA1, and 3 different EKLF-GATA1 fusion pLenti V5 topo expression constructs. All inserts were fused to a V5 epitope at the C-terminus with the transactivation and DNA-binding domains indicated. F1, F2, and F3 represent 3 finger domains of EKLF; CF and NF represent C- and N-fingers of GATA1; R1, R2, and R3 represent 3 regions of the transactivation domain of GATA1. (D) Long (L), medium (M), or short (S) form of EKLF, GATA1, EKLF-GATA1, or vector only (V) were transiently transfected into 293FT cells and then harvested 48 hours after transfection and subjected to Western blotting analysis using anti-V5, EKLF, or GATA1 antibodies. Mo indicates mock-transfected 293FT cells.