TP53INP1 is a target of miR-155 in MCF-7 cells. (A) Putative binding sites of miR-155 in the TP53INP1 3'UTR (white sequences) predicted by TargetScan. (B) Sketch of the construction of pMIR-TP53INP1-3U or pMIR-TP53INP1-3U-M vectors. The mutant binding site is underlined. (C) TP53INP1 protein level was measured by western blot at 72 h post-transfection. Data are presented as mean ± SD. **P < 0.01 and *P < 0.05 versus Con, miR-155 m NC or miR-155i NC. (D) miR-155 m down-regulated luciferase activity controlled by wild-type TP53INP1 3'UTR, but did not affect luciferase activity controlled by mutant TP53INP1 3'UTR. *P < 0.05 versus pMIR-TP53INP1-3U+155 m NC and **P < 0.01 versus pYr-MirTarget+155 m, pMIR-TP53INP1-3U-M+155 m. All experiments were repeated at least three times.