Figure 7. Genetic study revealed a C/ebpα-independent erythropoietic function of Trib2.

(A) Absence of C/ebpα expression in Mx1-Cre+; C/ebpα^F/F mice after poly I:C treatment. Trib2^+/+; C/ebpα^F/F, Trib2^−/−; C/ebpα^F/F, Trib2^+/+; Mx1-Cre+; C/ebpα^{F/ F}, and Trib2^−/−; Mx1-Cre+; C/ebpα^F/F mice were all injected with poly I:C. Three weeks later, total bone marrow cells were isolated and subjected to Western blotting with specific antibodies as indicated. (B–F) Deletion of Trib2 reduces erythroblast differentiation in C/ebpα^F/F and C/ebpα^Δ/Δ genetic backgrounds. (B) A representative FACS profile for each mouse group (as indicated on top of panels). The percentage of CD11b⁺ Gr-1⁺ cells (upper panels) or Ter119⁺ cells (lower panels) is indicated in each panel. Statistical analysis of granulocyte data (B, upper panels) is shown in (C,D), and that of erythroblasts (B, lower panels) is shown in (E,F). The graphs show the mean and S.E.M., n = 7–18 for each group. *P < 0.05 compares between the indicated groups. **P < 0.01 compares between the indicated groups. ***P < 0.005 compares between the indicated groups. NS: no significant difference. (G) Colony forming unit assay of erythrocytes (CFU-E) was performed for total bone marrow cells isolated from Trib2 and C/ebpα knockout mice, as indicated. The graph shows the mean and S.E.M., n = 6–11 for each group. *P < 0.05 compares between the indicated groups.