Wnt3a^−/− HSC have severely reduced long-term repopulation capacity as revealed by failure to repopulate secondary recipients. Total BM cells from primary recipient mice were retransplanted into lethally irradiated secondary Ly5.1 recipients. (A) Repopulation efficiency was analyzed in peripheral blood at the indicated time points. (B) Ly5.2 LSKs contribution toward myeloid (CD11b⁺), B-lymphoid (CD19⁺) and T-Lymphoid (CD3⁺) lineages measured in peripheral blood at the indicated time points. (A,B) Graphs show mean plus or minus SD of 7 mice in each group (Wt and Wnt3a^−/−). (C) Thirteen weeks after transplantation repopulation was analyzed in the hematopoietic organs. Numbers in quadrants indicate the percentage of total Ly5.1 or Ly5.2 cells in the BM of the recipient mice. CD45.1⁻CD45.2⁻ double negative cells constitute erythrocytes and megakaryocytes. (D) Percentage of total Ly5.2 cells in the BM of the recipient mice. The averages are indicated by a dash. (E) HSC compartment analysis in the secondary recipient mice. LSK cells were gated and analyzed for Ly5.2 expression. (F) Frequency of Ly5.2 LSK cells in the BM of the recipient mice. The averages are indicated by a dash. (C-F) Data represent 7 mice in each group. P values are indicated in the graphs. Results are representative of 3 independent experiments.