FL/HO-1^−/− cells express higher levels of TfR and globin and contain less ferritin after EPO-induced differentiation. (A) qRT-PCR showing TfR mRNA levels in wild-type FL and FL/HO-1^−/− cells. (B) Flow cytometry analysis showing cell membrane TfR levels of wild-type FL and FL/HO-1^−/− cells at 0, 24, and 48 hours (h) of EPO-induced differentiation. (C) qRT-PCR showing globin mRNA levels in wild-type FL and FL/HO-1^−/− at 0, 24, and 48 hours of EPO-induced differentiation. (D) Representative western blot showing TfR, ferritin, and globin protein levels of wild-type FL and FL/HO-1^−/− cells at 0, 24, and 48 hours of EPO-induced differentiation. (E) Densitometric analysis of TfR, ferritin, and globin protein levels normalized to β-actin. *Statistical significance (P < .05) when compared with FL/HO-1^+/+ cells at the time point 0 hours. †Statistical significance (P < .05) when compared with FL/HO-1^+/+ cells at time point 24 hours. φStatistical significance (P < .05) when compared with FL/HO-1^+/+ cells at time point 48 hours. Error bars of graphs represent standard deviation of 3 independent experiments (n = 3). **P < .001.