miR-145 regulates erythroid-megakaryocytic differentiation. (A) Relative to an shRNA-targeting Renilla luciferase (shluc), overexpression of miR-145, but not overexpression of miR-143, promotes erythroid relative to megakaryocytic differentiation in CD34⁺ progenitors. The ratios of cells from the megakaryocytic and erythroid lineages, indicated on the y-axis, were assessed by flow cytometry with antibodies against CD41 (for the megakaryocytic lineage) and GlyA (for the erythroid lineage), respectively. Similar results were obtained with the early erythroid marker CD71. (B) Relative to an shRNA-targeting Renilla luciferase (shluc), expression of an miRNA sponge targeting miR-145 promotes megakaryocytic relative to erythroid differentiation in CD34⁺ progenitors as assessed in Figure 1A. (C) Quantitative RT-PCR was performed for miR-145 in CD34⁺ progenitors from healthy persons (control), MDS CD34⁺ progenitors wild-type for 5q (5q diploid MDS), and in CD34⁺ progenitors from patients with the 5q− syndrome (5q− MDS). Expression levels were normalized to snoRNA-142 and then log₂ normalized. Values represent the mean of 4 replicates. (A-B) Values are mean ± SEM with propagated error. These experiments were performed in triplicate and replicated twice. *P < .05. ***P < .0005.