To assess the effects of Prmt1 loss on the propagation of leukemia, we transduced BM cells from 5‐FU‐treated Prmt1fl/fl; Cre‐ERT2 or Prmt1fl/fl mice with BCR‐ABL‐GFP retrovirus and transplanted them into sublethally irradiated recipients. Here, MAPK3 is linked to leukemia.