Gfi1 regulates miR-21 and miR-196B during myelopoiesis. TaqMan analysis of miR-21 and miR-196B in the human HL60 cell line treated with (A) ATRA or (B) PMA, or (C) the human U937 cell line treated with PMA. Immunoblot of Gfi1 or Beta-actin (inset). (D) TaqMan analyses of Gfi1, miR-21, and miR-196b expression in sorted wild-type CMPs and GMPs. (E) TaqMan analyses of miR-21 and miR-196b expression in sorted Gfi1+/+ and Gfi1−/− GMPs. (F) TaqMan analysis of miR-21 and miR-196b expression in phenotypically wild-type sorted GMPs, 36 hours after in vitro OHT-induced Cre-ERt2 activation to mediate deletion of floxed Gfi1 alleles. *P < .05; **P < .01; ***P < .001.