STRC activity failure in Gfi-1^−/− BMCs is rescued by Id2 reduction. (A) Western blot analysis showing heterozygosity at the Id2 locus results in reduced expression of Id2 protein levels in Gfi-1^−/− mice. β-actin was used to demonstrate equal loading of protein. (B) STRC activity failure of Gfi-1^−/− BMCs is rescued by reducing Id2 levels. Schematic representation of transplantation experiment (top). Survival of transplant recipients by 90 days (bottom). Recipient mice were lethally irradiated with 9.5 Gy then transplanted with 1 × 10⁶ BMCs of the indicated genotype (n = 5 for each group except “no cells,” where n = 3).