SF3B1 mutations enhance the leukemogenicity of hematopoietic cells expressing the inv(3)(q21q26) allele. (A) Schema of generation of CD45.2 Mx1-cre inv(3) Sf3b1^K700E/WT mice (left) and schema of in vitro and in vivo analyses of hematopoiesis from these mice and single-mutant controls. (B) Number of myeloid colonies on first to fifth plating of Mx1-cre inv(3) Sf3b1^K700E/WT mice and controls. (C) Box-and-whisker plots of white blood cell count (WBC), hemoglobin, and mean corpuscular volume (MCV) from CD45.1 recipient mice following 8.5 months of transplantation of CD45.2 mice from panel A. For box-and-whiskers plots throughout, bar indicates median, box edges first and third quartile values, and whisker edges minimum and maximum values. (D) Representative fluorescence-activated cell sorter plots of CD45.2⁺ LSK (lineage-negative Sca1⁺ and c-Kit⁺) and LK (lineage-negative Sca1⁻ and c-Kit⁺) cells from BM of CD45.1 recipient mice at 4 months posttransplant. % of cells within gate is shown. (E) Box-and-whisker plots of percentage of BM CD45.2⁺ LSK, multipotent progenitor cells 2 and 3 (MPP2 and MPP3, respectively), and common myeloid progenitor (CMP) cells. (F) % of CD11b⁺Gr1⁺ and B220⁺ cells among CD45.2⁺ cells in peripheral blood over time following transplantation. Mean ± standard deviation are shown. (G) Representative hematoxylin-and-eosin stain (original magnification ×100) of spleen of CD45.1 primary recipient mice. Scale bars, 400 μm. (H) Kaplan-Meier survival curve of primary CD45.1 recipient mice. P values were calculated by log-rank test. (I) Kaplan-Meier survival curve of secondarily transplanted CD45.1 recipient mice following sublethal irradiation (4.5 Gy). P values were calculated by 2-sided Student t test or log-rank test. *P < .05, **P < .01, ***P < .001, and ****P < .0001. chr., chromosome.