Fig. 4. Modulation of ß-catenin signaling regulates TCF/LEF signaling. ES cells were stably transfected with the constructs indicated (A). To test the activity of these constructs, we transiently transfected HEK293 cells with the constructs indicated and a TOPFLASH plasmid containing the TCF/LEF promoter driving a luciferase reporter gene (B). The full-length and N-terminal truncations were able to stimulate the TCF/LEF promoter but the C-terminal truncation, the armadillo truncation, and the N-plus C-terminal truncation constructs did not stimulate the promoter. TCF/LEF driven transcription was also increased by increasing the amount of ß-catenin transfected into the cells.