Flow cytometric analysis of EYFP expression in fetal liver cells. E14.5 fetal liver cells harvested from embryos after maternal tamoxifen (TAM) injections at E9.5 (0.5 mg), E10.5 (1 mg), and E11.5 (2 mg). (A) Tamoxifen-dependent recombination was detected in end-SCL-Cre-ER^T;R26R-EYFP total fetal liver cells (range, 0.5%-3.3%), whereas no Cre activity was detected in fetal livers of R26R-EYFP embryos. Recombination efficiencies within different end-SCL-Cre-ER^T;R26REYFP fetal liver cell populations: (B) Ter119⁺ (range, 0.3%-2.7%) and Mac-1⁺ (range, 2.4%-8.8%); (C) ckit⁺Sca-1⁺lineage^- (range, 14.8%-27.5%); and (D) Flk-1⁺lineage^- (range, 32.6%-48.1%). Indicated percentages represent means (n = 3). FSC indicates forward light scatter.