Enhanced repopulating capacity of Slug^−/− HSCs in reconstituted mice after 5-FU administration. (A) Diagram of in vivo HSC repopulating assay. Donor BM cells from Slug^+/− or Slug^−/− mice (CD45.2⁺) were injected together with competitor BM cells (CD45.1⁺/CD45.2⁺) into recipient mice that received a prior 13-Gy irradiation. A single dose of 5-FU (300 mg/kg body weight) was injected into these reconstituted mice at 2 months after BM transplantation. Ratio of donor- and competitor-derived cells in peripheral blood was determined before and after 5-FU treatment by flow cytometric analysis. (B) A representative flow cytometric analysis of test donor-derived hematopoietic cells before and after 5-FU injection (1 and 2 months). (C-D) Enhanced repopulating potential of Slug^−/− HSCs in vivo after 5-FU treatment. The percentage of Slug^−/− test donor-derived cells (CD45.2⁺) within the total donor-derived cell population (CD45.2⁺ cells and CD45.1⁺/CD45.2⁺ cells) increased in Slug^−/− BM-reconstituted mice (n = 4) at 4 months after 5-FU treatment (C). In contrast, the ratio of Slug^+/− test donor-derived cells did not significantly change in Slug^+/− BM-reconstituted recipients (n = 4) after 5-FU treatment (D).