Bone marrow iron is absent in bone marrow aspirates and sections of IRP2^-/- and IRP1^+/- IRP2^-/- mice. Perls stain (Prussian blue with safranin counter-stain) of WT (IRP1^+/+ IRP2^+/+) shows abundant iron stores, whereas iron is virtually undetectable in bone marrow aspirates of IRP1^+/+ IRP2^-/- and IRP1^+/- IRP2^-/- animals (A). In lightly fixed bone marrow biopsies, iron is visible in WT but not in IRP2^-/- and IRP1^+/- IRP2^-/- animals (top panel, B). On higher magnification, iron is detectable in WT macrophages (arrowhead points to blue iron deposits within brown cell identified as a macrophage by antibody to ED1 in middle row, B) and as siderotic granules in erythroid precursors (arrows). In bottom panel, antibody to TER-119 indicates erythroid lineage cells, but siderotic granules cannot be seen because the brown anti-TER-119 stain obscures them. Bone sections were obtained from age-matched 12-month-old females. Imaging was performed using a Nikon Eclipse E600 microscope (Nikon Instruments, Melville, NY) equipped with a 10×/0.45 objective lens (B, top panels) or a 60×/1.4 oil-immersion objective lens along with Nikon Type A immersion oil (A; B, middle and bottom panels). Images were captured with a Nikon DXM 1200F digital camera and Nikon ACT-1 2.62 imaging software. Images were processed with Adobe Photoshop 7.0 (Adobe Systems, San Jose, CA) and Adobe Illustrator 10.0 software programs.