Lack of Dnmt3a accelerates Nras driven malignancy. (A) Number of colonies per plate after single green fluorescent protein (GFP)-positive stem and progenitor cells were sorted into individual wells of 96-well plates (N = 3 plates per genotype/transduction). Representative of 2 independent experiments. (B) Kaplan-Meier survival curve of mice transplanted with WT HSCs transduced with MSCV-IRES-GFP (n = 7) or MSCV-NrasG12D-IRES-GFP (n = 10) and mice transplanted with Dnmt3a-KO HSCs transduced with MSCV-IRES-GFP (n = 7) or MSCV-NrasG12D-IRES-GFP (n = 10) (median survival of WT-NrasG12D mice: 83 days; KO-NrasG12D: 27 days; P < .0001). Representative of 2 independent experiments. Red blood cell (RBC) counts (C) and WBC counts (D) 3 weeks after transplant of WT or Dnmt3a-KO HSCs transduced with GFP or NrasG12D (n = 10 mice for each genotype transplanted with NrasG12D; n = 7 mice for each genotype transplanted with GFP). (E) Spleen weights of mice sacrificed at 10 weeks posttransplant. Error bars represent mean ± SEM. (F) Immunophenotyping of bone marrow from mice transplanted with WT HSCs transduced with MSCV-IRES-GFP or MSCV-NrasG12D-IRES-GFP and Dnmt3a-KO HSCs transduced with MSCV-IRES-GFP, stained for myeloid (My) and B cells (indicated with letter B). Parent gate is live; CD45.2⁺GFP⁺. (G) Wright-Giemsa staining of bone marrow (BM) touch preps showing dysplastic erythroid precursors with irregular nuclear contours and peripheral blood smears, and a hematoxylin and eosin (H&E)-stained bone marrow section showing dysplastic megakaryocytes with bizarre-shaped nuclei from mice transplanted with Dnmt3a-KO HSCs transduced with MSCV-IRES-GFP or MSCV-NrasG12D-IRES-GFP. Bars represent 20 μm. ^*P < .05, **P < .01, ***P < .001.