Analysis of Tfr2 and Epor in isolated erythroblasts. BM cells from control and Tfr2^BMKO mice maintained with an IB diet were sorted as described in the text. (A) Gating strategy for freshly isolated bone marrow erythroid subsets: R3, R4, R5, and R6. Nucleated cells were selected and subsets gated based on Ter119 and CD71. (B) Flow cytometry analysis of BM cells stained with antibodies against Ter119 and CD71. Histograms show the percentage of cells in stage R3, R4, R5, and R6. The number of events is reported in supplemental Table 3. (C-D) mRNA expression of Tfr2 (C) and Epor (D) relative to Gapdh in the R3, R4, and R5 stages. mRNA expression ratio was normalized to the R3 control mean value of 1. mRNA expression ratio was normalized to the control mean value of 1. Mean values of 3 samples for genotype (controls, Tfr2^BMKO) and stage (R3, R4, R5, R6) are graphed. Error bars indicate standard error. Asterisks refer to a statistically significant difference. *P < .05; ***P < .005.