Mice overexpressing miR-92a develop erythroleukemia. (A) Quantitative RT-PCR analysis of precursor miR-92a expression in the spleens of empty vector control (n = 6) and miR-92a mice, where n = 4, 12 weeks after infection. Results were normalized relative to β-actin expression in all experimental samples. Experiments were performed in quadruplicate, where error bars represent SD; ***P < .0005. (B) Survival analysis of mice injected with miR-92a (n = 26) or empty vector control (n = 18), in 3 independent experiments. (C) miR-92a overexpression (n = 8) leads to the development of leukemia associated with characteristic disease symptoms of increased spleen weight, and reduced body weights/hematocrit levels, where error bars represent SD; **P < .005. (D) Representative photograph of spleens from empty vector control and miR-92a mice 12 weeks after infection (top panel). H&E stained paraffin sections of isolated spleens from 12-week-old mice injected with miR-92a and empty vector control retroviruses (scale bar, 1 mm). Data are representative sections from 3 staining experiments (bottom panels). (E) Frequency of hematopoietic cell surface marker expression 6 weeks after infection, as a percentage of total splenocytes isolated from uninfected, empty vector control and miR-92a injected mice, where n = 5. Values represent the mean % ± SD; *P < .05. (F) Numbers of CSC1 colonies (CFU-GEMM, BFU-E, and CFU-GM) observed in an in vitro colony formation assay on methylcellulose for the indicated groups (n = 5), where error bars represent SD; **P < .005. Colony counts were performed in triplicate after 5 to 14 days of culture.