Enhanced proliferation and diminished myeloid differentiation of hematopoietic cells. CD34⁺ bone marrow cells from healthy individuals were transduced with lentivirus-based green fluorescent protein (GFP)-tagged RUNX1 mutants (p.Arg135Gly or p.Arg139Gly) or red fluorescent protein (RFP)-tagged CSF3R mutant (d715) alone, cotransduced with RUNX1 and CSF3R mutants, or cotransduced with control GFP- and RFP-tagged lentiviral constructs. Transduced cells were treated with 10 ng/mL of G-CSF. (A) Cell number was evaluated on days 2 and 4 of culture by estimation of RFP⁺/GFP⁺ cells using fluorescence-activated cell sorter. (B) G-CSF–triggered myeloid differentiation was evaluated on day 8 of culture. Data represent means ± standard deviations and are derived from 2 independent experiments, each in triplicate (*P < .05).