Anemia in all Apc haploinsufficient mice is caused by a block at an early erythroblast stage. (A) Splenocytes were isolated from Apcfl/+ control mice, Apcdel/+ mice, or Apcdel/+mice crossed with Egr1+/−(E), Tp53+/− (P), or Egr1+/−, Tp53+/− (EP), and flow cytometric analysis of immature erythroblasts (CD71+Ter119+), mature erythroid cells (CD71−Ter119+), granulocytes (Gr1+Mac1+), B cells (CD19+), and T cells (CD4+ or CD8+) was performed when mice displayed severe anemia. (B) Flow cytometric analysis of spleen cells from a representative, anemic Apc haploinsufficient mouse. The 4r erythroid cell populations from least to most differentiated are indicated as R1 to R4. R1, pro-erythroblasts; R2, basophilic erythroblasts; R3, polychromatophilic erythroblasts; R4, orthochromatophilic erythroblasts.
