<i>β</i>-catenin and TCF-4 up-regulate mRNA levels of <i>ABCD2</i>.

<p>HepG2 cells were cotransfected with Flag-tagged constitutively active <i>β</i>-catenin (Flag-catenin 4A) and Myc-tagged TCF-4 expression plasmids. (A) At 48 h after transfection, mRNA was isolated from transfected cells. The levels of <i>ABCD1</i> and <i>ABCD2</i> mRNA were measured by real-time PCR and were normalized to <i>GAPDH</i> expression (upper panel). Data represent the mean (± SEM) of triplicate experiments. Total cell lysates harvested from transfected cells were immunoblotted with the indicated antibodies (lower panel). Protein expression of <i>β</i>-actin was used as a loading control. **<i>p</i><0.001; ns, not significant; control vector transfected cells <i>versus β</i>-catenin and TCF-4 transfected cells. (B) HepG2 cells were transfected with either scrambled or <i>β-catenin</i> siRNA. At 3 days after transfection, mRNA was isolated from transfected cells. The levels of <i>ABCD1</i> and <i>ABCD2</i> mRNA were measured by real-time PCR and normalized to <i>GAPDH</i> expression (upper panel). *<i>p</i><0.05; ns, not significant; scrambled transfected cells <i>versus β-catenin</i> siRNA transfected cells. Efficacy of silencing was verified by western blotting with anti-<i>β</i>-catenin antibody (lower panel). Protein expression of <i>β</i>-actin was used as a loading control.