IGFBP2 has little cell-autonomous effect on HSCs. (A) Lin⁻Sca-1⁺Kit⁺Flk2⁻CD34⁻, hematopoietic CD45⁺, and nonhematopoietic CD45⁻ stromal cells were freshly isolated from BM, and IGFBP2 gene expression was determined by real-time RT-PCR (n = 4-5). (B) Five hundred freshly isolated CD45.2 Lin⁻Sca-1⁺Kit⁺Flk2⁻CD34⁻ cells from WT or IGFBP2-null mice were cotransplanted with 1 × 10⁵ CD45.1 total BM cells into CD45.1 recipients, and the ST and LT donor repopulating activities were evaluated at indicated time after transplantation (n = 8). (C) Different donor lineages from long-term repopulation were determined. Representative data from 1 of 2 independent experiments that gave similar results are shown.