Cdx4 induces an expansion of erythroid cells in vivo and an AEL in transplanted mice. (A) Spleen colony formation (CFU-S) was compared between Cdx4 (n = 4) and control vector (n = 5) transduced HSPCs. Transduced cells were sorted 72 hours after retroviral infection and injected in the tail vein of lethally irradiated mice 12 days before euthanasia. CFU-S frequency was calculated per 10⁴ cells. Data are represented in a Log10 scale. Values are shown as mean ± standard error of the mean. Significance was calculated by the Mann-Whitney U test (**P < .01). (B) Spleen cells from panel A were stained and analyzed by fluorescence-activated cell sorting for the expression of myeloid and erythroid markers. The bar graph shows the mean percentage (± standard error of the mean) myeloid marker (Gr-1⁺/Mac-1⁺, Gr-1⁺/Mac-1⁻, Gr-1⁻/Mac-1⁺) and erythroid marker (CD71⁺/Ter119⁻, CD71⁺/Ter119⁺, and CD71⁻/Ter119⁺)-expressing cells and refers to the GFP⁺ compartment. Significance was calculated by the Mann-Whitney U test (*P = .0159). (C) Kaplan-Meier survival curves of primary (n = 12) and secondary (n = 22) mice transplanted with 5FU-stimulated BM cells expressing Cdx4 or the vector control. Mantel-Cox log-rank test was performed on mice injected with control vector vs Cdx4 (primary recipient mice; **P = .0045) and Cdx4 (secondary recipient mice; **P = .0019), respectively. Mantel-Cox log-rank test on all 3 survival curves was also found significant (****P < .0001).