Expression of miR-155 in FLT3-ITD BM promotes expansion of myeloid progenitors. (A) Expression level of miR-155 in WT, 155^−/−, FLT3-ITD, and FLT3-ITD 155^−/− mice in total BM determined by qRT-PCR. Expression normalized to 5S ribosomal RNA. (B) Total BM cellularity in different mouse groups. (C) Total numbers of CD11b⁺ Gr1⁺ cells, CD11b⁺ Gr1^– cells, B220⁺ cells, and Ter119⁺ cells in the BM of different mouse groups determined by flow cytometry. (D) Gating strategy for flow cytometric analysis of LKS and myeloid progenitor (Lin^–, c-Kit⁺, Sca1^–) populations. (E) Total number of LKS cells in BM determined by flow cytometry. (F) Total number of myeloid progenitor cells (Lin^–, c-Kit⁺, Sca1^–) in BM determined by flow cytometry. (G) Total common myeloid progenitor (CMP) (left), granulocyte-monocyte progenitor (middle), and megakaryocyte-erythrocyte progenitor (right) cells in BM determined by flow cytometry. Data are representative of at least 3 independent experiments. Each point represents a sample from 1 mouse. *P ≤ .05; **P ≤ .01; ***P ≤ .001; ****P ≤ .0001; ns, P > .05.