Mice positive for donor engraftment were defined as those with >1% CD45.2⁺GFP⁻ or CD45.2⁺GFP⁺ cells (for WT or KI cells, respectively) in the peripheral blood in both the lymphoid and myeloid gates. The proportion of positive mice is given as (number of positive mice)/(number of analyzed mice). Representative data from 2 independent experiments are shown.