Hematopoietic defect is cell autonomous. (A) Outline of transplantation experiments. A total of 100 purified HSCs from pIpC-treated Eng^fl/Δ;Mx1-Cre⁺ mice (blue) or control mice (red) was injected into lethally irradiated CD45.1 recipient mice, along with 2 × 10⁵ CD45.1 total BM competitor cells. For subsequent serial transplantation, 1 × 10⁶ total pooled BM cells were injected into lethally irradiated CD45.1 recipients. (B) Percentage of CD45.2 chimerism in primary to tertiary recipients (left to right) at 6 and 16 weeks following HSC transplantation confirm defective hematopoietic reconstitution in tertiary recipient mice. Box plot whiskers represent minimum and maximum values for each cohort. (C) Contribution of CD45.2⁺ donor cells to macrophages, granulocytes, B lymphocytes, and T lymphocytes. Error bars indicate standard error of the mean for each cohort. *P < .05.