Objective        To study the effect of miR-125b on expression of core-binding factor beta (Cbfβ) in mouse C3H10T1/2 cells.       Methods        Mouse C3H10T1/2 cells were transfected with microRNA negative control

miR-125b mimics and anti-miR-125b

respectively. Expressions of Cbfβ protein and mRNA in C3H10T1/2 cells were detected by Western blotting and RT-PCR

respectively. Inserting sequences of miRNA negative control

wild type and mutation were synthesized according to the 30 bases adjacent to the miR-125b target on the Cbfβ 3′UTR in PicTar database and linked to the PmiR-report plasmids digested by HindⅢ and SpeⅠ. The 293 T cells were co-transfected with miRNA negative control and miR-125b mimics. The activity of luciferase was detected by dual luciferase report assay.       Results        The over-expression of miR-125b inhibited the expression of Cbfβ protein and mRNA in C3H10T1/2 cells (P0.05)

while the anti-miR-125b-transfected C3H10T1/2 cells promoted the expression Cbfβ protein and mRNA (P0.05). The miR-125b suppressed the activity of luciferase  on the Cbfβ 3′UTR.       Conclusion        Exogenous miR-125b can act on the Cbfβ 3′UTR

and thus down-regulate the expression of Cbfβ in C3H10T1/2 cells.