Anp32b deficiency reduces long-term repopulation capacity of HSCs. (A) Primary competitive transplantation assay was conducted with Anp32b^+/+ and Anp32b^−/− BM CD45.2 cells (6 × 10⁵) along with 6 × 10⁵ BM cells from CD45.1 competitor. Percentages of donor-derived cells in PB were analyzed at the indicated time points (n = 6). (B-C) Frequencies of donor-derived LSK cells, LT-HSCs, ST-HSCs, and MPPs (B) and lineage cells (C) in BM were analyzed at 16 weeks after transplant (n = 6). (D) Secondary transplantation was performed with total BM cells (1 × 10⁶) from primary recipients in panel A at 16 weeks after transplant. Percentages of donor-derived cells in PB were analyzed at the indicated time points (n = 6). (E-F) Primary transplantation was conducted with FACS purified LT-HSCs (2 × 10³) from Anp32b^+/+ and Anp32b^−/− BM cells along with 6 × 10⁵ BM cells from CD45.1 competitor (E, n = 6). Secondary transplantation was performed with total BM cells (1 × 10⁶) from primary recipients at 16 weeks after transplant (F; n = 5). Percentages of donor-derived cells in PB were analyzed at the indicated time points. (G) Schematic strategy of evaluation of the in vivo effect of ANP32B knockdown in human cord blood CD34⁺ cells. (H-I) Representative FACS plots (i) and percentages (ii) of human CD34⁺ and CD45⁺ cells engrafted in PB cells (H) and BM cells (I) 6 weeks after transplantation (n = 5). Error bars denote mean ± SEM. Statistical significance was determined by a 2-tailed unpaired Student t test (A-F, H-I). All animal experiments were repeated at least twice with similar results, and the results of 1 representative experiment are shown.