PRMT1 and chronic myelogenous leukemia, BCR-ABL1 positive: T315I mutation in BCR‐ABL is a representative and stubborn point mutation that confers resistance to imatinib.[30] To explore whether PRMT1 is also required for CML LSCs harboring T315I BCR‐ABL, we transduced BM cells from Prmt1fl/fl; Cre‐ERT2 or Prmt1fl/fl mice with T315I‐BCR‐ABL‐GFP retrovirus and transplanted them into sublethally irradiated recipient mice to induce CML (Figure S5A, Supporting Information).