Fig. 7. ß-catenin and PITX2 synergistically activate the LEF-1 promoter independent of the WRE. (A) CHO cells were transfected as in Fig. 6, with CMV-PITX2C or CMV-ß-catenin S37A, or both, and the CMV empty expression vector with the appropriate LEF-1 luciferase reporter constructs. The activities are shown as mean fold activation compared with the LEF-1 promoter plasmid without PITX2 or ß-catenin expression and normalized to ß-galactosidase activity (± s.e.m. from four independent experiments). (B) GST-ß-catenin pull-down assay with bacterial expressed and purified PITX2A protein (200 ng). PITX2A binds to immobilized GST-ß-catenin. The bound protein was detected by western blot using a PITX2 antibody. As a control GST-beads were incubated with purified PITX2A to show the specificity of binding to ß-catenin.