Granulopoiesis in G193X Elane × Perk^−/− bone marrow chimeras. (A) Fetal liver cells from 12-15 dpc Elane^G193X/+Perk^+/− mice (Ly5.2) intercrosses were transplanted into irradiated wild-type (WT Ly5.1) mice. Neutrophil counts in the blood (B) and bone marrow (C) were measured 12 weeks after transplantation. (D) Gr-1⁺ myeloid cells were isolated from the bone marrow as described in “Peripheral blood and bone marrow analysis,” RNA was prepared, and real-time RT-PCR for the indicated gene performed. Shown is the mRNA expression relative to β-actin. Data represent the means ± SEM of 6-14 mice. *P < .05 compared with WT cells.