Sox6^–/– erythroid cells have decreased survival and proliferation rates in vitro. (A) AnnV/7-AAD FACS profiles of control and Sox6^–/– erythroid cells cultured on fibronectin with 0.2 U/mL Epo for 12 and 48 hours. The quadrants in each plot correspond to live cells (AnnV^–/7-AAD^–), apoptotic cells (AnnV⁺/7-AAD^–), dead cells (AnnV⁺/7-AAD⁺), and necrotic cells (AnnV^–/7-AAD⁺). (B) Graphs showing the percentages of apoptotic (AnnV⁺/7-AAD^–) proerythroblasts and erythroblasts in cell cultures on fibronectin for 12 hours with the indicated concentrations of Epo. (C) BrdU incorporation assay in control and Sox6^–/– erythroid cells cultured on fibronectin with 0.2 U/mL Epo for 12 hours and 48 hours. The percentages of BrdU⁺ cells are indicated. (D) Graphs showing the percentages of BrdU⁺ proerythroblasts and erythroblasts in cell cultures on fibronectin for 12 hours with the indicated concentrations of Epo.