Fig. 2.

Deletion of Runx1 decreases EMPs in the yolk sac, but not CFU-Cs in the fetal liver. (A) Yolk sac EMPs, AGM+U+V CFU-Cs and fetal liver CFU-Cs [mean±s.e.m. per embryonic equivalent (ee)] following deletion of Runx1 with Actb-Cre^ERT. Embryonic ages in somite pairs (sp) and embryonic days (E) on the x-axis represent the stage of the embryo when harvested for methylcellulose colony assays, with the deletion initiated 24 hours earlier. Black asterisks indicate significant differences (P≤0.05) between colony numbers in f/f; Cre versus f/f and f/+ embryos. Orange asterisks indicate significant differences between f/f; Cre and f/+; Cre embryos. The difference between f/f; Cre and f/+; Cre at 18-25 sp (E9.0) in yolk sac is statistically significant (P=0.06). (B) Deletion frequency in Runx1^f/+; Actb-Cre^ERT yolk sac, AGM+U+V, and fetal liver EMPs/CFU-Cs represented as percentages of colonies (mean±s.e.m.) that had no deletion (f/+) or deletion (Δ/+) of the floxed allele. The average deletion efficiency in combined experiments was 64.7% (±4.04). Data from embryos in which the average deletion frequency was <30% were excluded from Fig. 2A. (C) Deletion frequency in Runx1^f/f; Actb-Cre^ERT progenitors represented as percentages of colonies (average±s.e.m.) that had deleted both (Δ/Δ), one (Δ/f) or no Runx1^f alleles (f/f). The average deletion efficiency was 61.4% (±19.1). The number of sample replicates and colonies are shown in supplementary material Tables S1, S2. All data were analyzed using Student’s unpaired t-test and are shown as mean±s.e.m.