Human and murine stress BFU-Es express embryonic/fetal β-globin genes. (A) Flow cytometry analysis of HbF in CD235a+ cells in human bone marrow cells cultured in SEDM (left) or cultured in steady-state erythropoiesis media (Epo + SCF at 20% O2) (right). (B) qRT-PCR analysis of β- and γ-globin expression in human bone marrow cells prior to culture (control), cultured in SEDM for 5 days (SEDM), cultured in SEDM for 5 days, then switched to stress BFU-E media Epo + BMP4 + SCF at 2% O2 for 3 days (SEDM + Diff) or cultured in steady-state conditions (Epo + SCF at 20% O2) (left). Expression is expressed as a γ-globin to β-globin ratio. The expression of BCL11a (L/XL) mRNA and protein was examined by qRT-PCR analysis (center) and by western blot (left), respectively, in human bone marrow cells cultured in SEDM for 5 days or steady-state conditions. (C) The expression of murine embryonic β-globin genes βH1 (left) and εy (center) and Bcl11a (right) was examined by qRT-PCR in murine bone marrow cells cultured in SEDM for 5 days (SEDM) and SEDM for 5 days and then switched to stress BFU-E media Epo + BMP4 + SCF at 2% O2 for 3 days (SEDM + Diff) or cultured in steady-state conditions (Epo + SCF at 20% O2). Data are mean ± standard error of the mean. (D) Schematic of stress erythroid progenitor development.
