Stat5-deficient erythroid cells display reduced IRP-2 expression and mRNA-binding activity. (A) Western blot analysis of primary wt and Stat5^−/− erythroblast lysates for IRP-1 (left panel) and IRP-2 (right panel). (B) Quantification of Western blot analysis from panel A (data are presented as means ± SD). Samples were normalized on eIF4E as levels and quantified using the Odyssey infrared imaging system. (C) Two representative lysates each of wt and Stat5^−/− erythroblasts were subjected to RNA-EMSAs for IRP-1 and IRP-2 using an IRE-RNA probe corresponding to the IRE of mouse ferritin heavy chain⁶⁴  (for experimental details, see Document S1). (D) Quantification of IRP-2–binding activity (data are presented as means ± SD; n = 4). *P < .05; **P < .01.