Haploinsufficiency of Gata2 improves erythropoiesis in Gata1s embryos. (A) Bar graph depicts the mean percentage of Ter119 expressing fetal liver cells from Gata1/Gata2 (G1/G2), Gata1/Gata2^het (G1/G2^het), Gata1s/Gata2 (G1s/G2), and Gata1s/Gata2^het (G1s/G2^het) embryos. (N > 3). (B) Representative flow cytometry plots of CD71/Ter119 erythroid staining of fetal liver cells isolated from male embryos of each genetic background. (C) Bar graph depicting the mean ratio of early erythroblasts (Ter119⁺/CD71⁺) vs late differentiated erythroid cells (Ter119⁺/CD71⁻) in panel B. (D) E12.5 fetal liver cells were isolated and cultured in methylcellulose medium supplemented with EPO to support erythroid colony formation. Bar graph represents the number of BFU-E of each of the genotypes. Mean ± SD are shown (N = 3). (E) Representative images of fetal liver erythroid cells after benzidine staining. Arrows indicate dark stained hemoglobin-containing cells. Bar graph represents mean number of benzidine stained cells out of the total fetal liver cells counted for each genotype. (F) Representative images of colonies from G1s/G2 and G1s/G2^het. A total of 5000 E12.5 fetal liver cells were cultured in methylcellulose supplemented with EPO and colonies were stained with benzidine. Dark staining indicates hemoglobin-containing colonies. Bar graph depicts mean number of benzidine-stained colonies from each genotype. **P ≤ .01, ****P ≤ .0001 (unpaired Student t test). Original magnification ×10 (E) and ×4 (F).