HSPC content in E14.5 CXCR4^+/+ and CXCR4^–/– livers. (A) CFC number in CXCR4^+/+ and CXCR4^–/– FL cells. Data represent the mean ± SD number of colonies for each genotype and for 2 dilutions of FL cells (10⁵ and 2 × 10⁵ cells plated per dish) in 3 independent experiments performed in duplicate. Colony numbers are expressed for 10⁵ cells. G indicates granulocyte; GM, granulocyte macrophage; GEMM, granulocyte erythrocyte megakaryocyte macrophage; and BFU-E, erythroid burst-forming unit. (B) The day 12 CFU-S potential of CXCR4^+/+ and CXCR4^–/– FL determined by injecting 5 × 10⁴ and 10⁵ cells for each genotype per recipient. The data represent the mean ± SD number of colonies scored for each genotype and for control uninjected mice. Results are expressed for 10⁵ cells (n = 3 independent experiments with 10 mice injected per dilution). (C) Representative flow cytometry analysis of hematopoietic stem cells staining using Hoechst 33342 as described by Goodell et al.³²  Afterward, CXCR4^+/+ and CXCR4^–/– FL cells were stained with lineage-specific antibodies and the stem cell markers Sca-1 and c-Kit. The dead cells were previously excluded by 7-AAD staining. The primitive Sca-1⁺ c-Kit⁺ and SP cells were analyzed in the CD45⁺ Lin^– gate and their relative percentages are shown.