ESL-1 mediates progenitor homing to the BM. (A) Design of the BM homing assays. Lethally irradiated mice were injected with experimental and DsRed+ competitor BM cells, which were allowed to home for 3 hours. Homed CFU-C were scored 7 to 10 days later and were differentiated on the basis of red fluorescence (WT-DsRed+) or no fluorescence, as illustrated in the micrographs. (B) Homing efficiencies of progenitors from each group, calculated as the ratios of homed CFU-C from each mutant donor relative to competing WT-DsRed+ progenitors, and corrected by the ratio of CFU-C injected. There were 6 to 8 mice per group from 3 independent experiments. Bars represent mean ± SEM. Data were analyzed by 1-way ANOVA using the Tukey multiple comparison test. (C) Relative expression of Fut4 and Fut7 in purified Lineage^NEG Sca-1+ cKit^HI cells (LSK), myeloid progenitors (MP), granulocyte-monocyte progenitors (GMP), and circulating neutrophils. Data show the mean ± SEM from 3 independent samples and was analyzed by an unpaired Student t test. (D) Western blot analysis of total ESL-1 protein and β-actin (load control) present in sorted Lineage^NEG cKit^HI progenitors (HPCs) and blood neutrophils (PMNs). Data are representative of 2 independent experiments, with increases of 10.0-fold and 10.3-fold in ESL-1 protein levels in HPCs relative to PMNs.