miR-145 loss provides a clonal advantage to hematopoietic progenitors. (A) CD34⁺ progenitors were infected with lentiviruses expressing a control shRNA (shluc), miR-143, miR-145, or 3 independent shRNAs targeting RPS14. Total cell number of CD34⁺ progenitors was assessed. Values are mean ± SEM (n = 3) with propagated error. P values are calculated via comparison with the shluc value for a given day. (B) CD34⁺ progenitors were infected with lentiviruses expressing a control cDNA (LacZ), Fli-1, or a sponge targeting miR-145, and total cell number was assessed as in panel A. P values are calculated via comparison with the LacZ value for a given day. (C) CD34⁺ progenitors were coinfected with (1) a control shRNA (shluc) or 3 independent shRNAs targeting RPS14 and (2) a control cDNA (LacZ) or the miR-145 sponge. Total cell number was assessed as in panel A. P values are calculated via comparison with the shRNA/LacZ value for a given day. **P < .005. ***P < .0005.