The maintenance of BM HSCs requires pfn1 function. (A) Representative flow cytometry profile of Lin−Sca-1+Kit+ cells from control and Sclpfn1 mice. (B) The frequency of LSKFC in the Sclpfn1 mouse was dramatically decreased compared with the control mouse (1.4% vs 0.01%) at day 14 after tamoxifen treatment. Deletion of pfn1 over time is indicated by the arrow. (B-C) Quantification of HSC (Lin−Sca-1+Kit+Flk2−CD34−) frequency and number in BM of control and Sclpfn1 mice (n = 5-8) at different time points (*P < .05). (D) Competitive reconstitution analysis of control and Sclpfn1 HSCs treated with tamoxifen for 4 days. BM CD45.2 cells (2 × 105 cells) from donor mice along with 2 × 105 freshly isolated CD45.1 competitor cells were transplanted into lethally irradiated CD45.1 recipient mice. The mice (n = 5 per group) were analyzed for engraftment through 16 weeks after transplant (*P < .05). (E) Multilineage contribution of donor cells in the recipients at 14 weeks after transplant (n = 5). (F) Control and Sclpfn1 donor cells (2 × 105 cells) along with 2 × 105 competitor cells were transplanted into lethally irradiated CD45.1 recipient mice. These primary transplanted mice (n = 5) were treated with tamoxifen at 8 weeks after transplant and were then analyzed for the engraftment from 2 to 17 weeks after tamoxifen treatment. (*P < .05). Deletion of pfn1 at 2 weeks after tamoxifen treatment is indicated by the arrow. (G) Multilineage contribution of donor cells in the recipients at 16 weeks after transplant (n = 5).
