HSPCs from young Runx3 KO mice show enhanced proliferative and mobilization ability when stimulated. (A) Schematic diagram showing an overview of the CFU-C assay, including serial replating. Colonies were scored 7 days after plating. (B,D) Colony-forming potential of (B) whole bone marrow (BM) cells and (D) BM KSL cells. Mean ± standard deviation (SD) is shown (n = 2/genotype). All colonies were counted from triplicate samples. Two independent experiments were performed. Asterisks represent significant differences (**P < .01; ***P < .001, Student t test). (C,E) Morphology of colonies formed on each plate. Representative plates in first and second platings from B and D are shown. (F-G) Flow cytometric analysis of the KSL and c-Kit⁺Sca-1⁻lineage⁻ (myeloid progenitor) compartment in the spleen at 6 weeks after pIpC treatment. Mean ± SD of percentage of (F) KSL and (G) myeloid progenitors in spleen is shown (n = 5/genotype). Three independent experiments were performed. n.s., no significant difference (Student t test). (H) G-CSF mobilization assay of cells from Runx3 KO mice (n = 7) and Runx3 WT mice (n = 5). Time course of progenitor cell numbers in 20 µL PB after in vivo G-CSF stimulation (300 μg/kg/day for 4 days) is shown. Mean ± SD of CFU-C numbers is shown. Asterisks represent significant differences (*P < .05; ***P < .001, Student t test).