Functional interaction between Ikaros and Gata1 during fetal hematopoiesis. (A) GATA-2– and GATA-1–dependent Ikaros expression in 13.5-day G1KD fetal liver cells. qRT-PCR assays were performed on GFP-sorted 13.5-day G1KD FL cells transduced with banshee (empty vector), banshee-shGata2, Migr1, and Migr1-Gata1 retroviral vectors. Means ± SD from 5 to 6 independent experiments are shown. *P = .004; #P = .0007. (B) Images of G1KD-Ikaros-null and G1KD-Ik^+/− fetuses at 3 different time points. (C) Histogram plots showing the cell numbers of E13.5 G1KD-Ikaros fetal livers before and after RCL. Data are shown as means ± SD (n = 5-6 fetal livers per group); *P < .001 relative to G1KD-Ikaros^+/+. #P < .001 relative to G1KD-Ikaros^+/−. (D) Bar graphs comparing the percentages of the CD71⁺/Ter119⁻ and CD71⁺/Ter119⁺ positive cells of Ik^+/+, Ik^+/−, and Ik^−/− fetal liver cells in a Gata1 Wt or G1KD background. Data are shown as means ± SD from 6 independent experiments; *P < .001 relative to G1KD-Ik^+/+. #P < .001 relative to G1KD-Ik^+/−. (E) Representative FACS plots of megakaryocytic subpopulations in E13.5 G1KD-Ik^+/− and G1KD-Ik^−/− fetal livers. (F) Histogram plots showing the increased percentage of the c-Kit⁺/CD41⁺ positive cells in the G1KD-Ik^−/− E13.5 fetal livers. Data are shown as means ± SD from 7 independent experiments. *P < .001 relative to G1KD-Ik^+/+; #P = .001 relative to G1KD-Ik^+/−. RCL, red cell lysis; Wt, wild type.