Generation and confirmation of Dox-inducible miR-125b knock-in mouse. (A) Schematic of knock-in design, with miR-125b precursor sequence flanked by splicing sites inserted in the 3′ untranslated region of enhanced green fluorescent protein (EGFP). The targeting vector was knocked into a Dox-inducible locus on the X chromosome, creating GFP-miR-125b cassette under the control of the tet response element (TRE) promoter. Neomycin (neo), under the control of phosphoglycerate kinase (PGK), is a selection marker for successfully recombined events. (B) Representative genotyping results from wild-type (WT), heterozygous (Het), and homozygous (Homo) i125b knock-in (K/I) mice. (C) Representative flow cytometry to show inducible GFP expression in peripheral blood and bone marrow cells from Ri125b mice with or without Dox water for 7 days. WT mice treated with Dox water were used as controls. (D) WT Mac-1⁺ or Ri125b GFP⁺/Mac-1⁺ myeloid cells were sorted from bone marrow after 7 days of Dox induction. Relative miR-125b expression was determined by quantitative reverse transcription polymerase chain reaction. U6 was used as a control. (E) miR-125b expression in Ficoll-purified bone marrow cells from 6 cytogenetically normal AML patients were determined. Relative expression to U6 small RNA are plotted. Data were aligned from low to high expression of miR-125b. Error bars represent standard deviations; n = 3 for technical replications.