Ccbe1^lacZ/lacZ fetal livers exhibit a specific defect in erythropoiesis. (A) Erythroblast maturation in Ccbe1^lacZ/lacZ and control fetal livers was assessed by staining for CD71 and Ter119 at E13.5. Note that the number of erythroblasts in the Ccbe1^lacZ/lacZ fetal liver was reduced at all stages of maturation. (B) Erythroblast maturation in Ccbe1^lacZ/lacZ and control fetal livers was also assessed by staining for CD44 and Ter119 at E13.5. (C) The fraction of Ter119⁺ erythroblasts in Ccbe1^lacZ/lacZ fetal livers is reduced at E13.5. (D) The fraction of CD45⁺Ter119⁻ cells in Ccbe1^lacZ/lacZ fetal livers is unchanged at E13.5. (E) Ccbe1^lacZ/lacZ fetal livers have normal numbers of Lin-cKit⁺Sca1⁺ hematopoietic stem cells at E13.5. (E-N) Ccbe1^lacZ/lacZ fetal livers have normal numbers of E-cadherin⁺ hepatocytes (F,G), LYVE1⁺ sinusoidal endothelial cells (H,I), PDGFRb⁺ vascular pericytes (J,K), vWF⁺ megakaryocytes (L,M), and Desmin⁺ stellate cells (N,O). Scale bars represent 25 μm.