A) Bone marrow cells from wild-type (WT) or IKKβΔ/Δ mice were stained for CD11b, CD45, Ter119 and CD71. CD11b-;CD45- cells were gated and the proportion of proerythroblasts, basophilic, polychromatic, and orthochromatic erythroblasts in nucleated bone marrow cells is shown on representative FACS plots. B) The average number of cells of each of erythroid subpopulation per hind leg is shown (n = 4). C) Equal number of marrow cells from wild type, IKKβΔ/Δ or p65Δ/Δ mice were plated in methylcellulose under conditions promoting erythroid maturation, and BFU-Es were enumerated after 8 days. Average number of colonies from 3 experiments is shown. D) Wild type bone marrow cells were plated in methylcellulose in the presence or absence of 1 μM Bay 65–1942, and BFU-Es were enumerated 8 days later (n = 3). Hematocrit was assessed in wild type or IKKβΔ/Δ mice after induction of hemolysis with E) PHZ 200 mg/kg or F) challenge with 250 mg/kg 5-FU. G) Neutrophil recovery after 5-FU. *-denotes p<0.01. **denotes p<0.001.