Increased repopulating activity of HSPCs from Mll^PTD/WT mice correlates with acquisition of an intrinsic self-renewal program. (A) A single-cell culture was performed in the presence of cytokines for 2 weeks. (B) Cytospin slides were prepared from individual clones and stained with Camco Stain Pak. Black arrow indicates megakaryocyte; red arrow, neutrophil; green arrow, monocyte; and blue arrow, poly-erythrocyte. (C) Frequency of lineage formation of LSK/SLAM⁺ or LSK/SLAM⁻ or GMP in WT or Mll^PTD/WT are shown in Table 1. (D) Frequency of CFU-Cs in the GMP population sorted from WT or Mll^PTD/WT during serial replating on methylcellulose in vitro. For the first-round plating, 1 × 10³ GMP cells were seeded per milliliter of hematopoietic methylcellulose colony-forming media. A total of 1 × 10⁴ cells were planted for next-round replating. The cells are assayed in triplicate dishes of 1 mL. *P < .05. (E) Proportion of CFU-Cs in serial replating. (F) Representative image of colonies from WT and Mll^PTD/WT GMP cells in third-round replating.