−2.8 kb GATA switch site regulates Gata2 expression in hematopoietic stem and progenitor cells, but is dispensible in erythroid cells. Gata2 expression within LT-HSC and MPP populations (LT-HSC defined as Lin^dimckit⁺Sca1⁺CD150⁺ and MPP defined as Lin^dimckit⁺Sca1⁺CD34⁺ or Lin^dimckit⁺Sca1⁺CD150⁻) from E12.5 fetal livers normalized to β-actin (A). Frequencies of LT-HSCs and MPPs in wild-type and Δ-2.8 fetal livers (B). Gata2 expression within CMP and MEP populations (with CMP defined as Lin^dimSca1⁻,c-kit⁺CD34⁺, FcγR⁻ and MEP defined as Lin^dim Sca1⁻c-kit⁺CD34⁻, FcγR⁻) from E12.5 fetal livers normalized to β-actin (C). Frequencies of CMPs and MEPs from wild-type and Δ-2.8 fetal livers (D). Gata2 expression was assessed by qPCR in Stage I through Stage IV sorted erythroid cells, corresponding to CD71^loTer119⁻ (committed erythroid progenitors, Stage I), CD71^hiTer119⁻ (proerythroblasts, Stage II), CD71^hiTer119⁺ (basophilic erythroblasts, Stage III), and CD71^loTer119⁺ (late erythroblasts, Stage IV) from wild-type and Δ-2.8 embryos. (E). Relative number of cells in Stage I-IV was determined in wild-type and Δ-2.8 E13.5 fetal liver cells, based on CD71 and Ter119 expression (F). Mean ± SEM. Statistical significance was assessed by 2-sided Student t test. *P ≤ .05 and **P ≤ .01.