MLLT3 and leukemia: To investigate whether immunoproteasome function is required for leukemia development in vivo, LMP7+/+ and LMP7−/− LSK cells were transduced with the KMT2A::MLLT3oncogene (MSCV-KMT2A::MLLT3–GFP) and a total of 7 × 104 transduced (GFP+) cells were injected into sublethally (7 Gy) irradiated recipient hosts (Supplementary Figure S3B).