FIGURE 5.

Elucidation of the TBE responsible for β-catenin·TCF4 transactivation in the SMC2 promoter. A, sequence alignment of SMC2 promoter in different species; Hs, Homo sapiens; Pt, Pan troglodytes; Mmt, Macaca mulatta; Rn, Rattus novergicus; Mms, Mus musculus. Conserved TBEs are highlighted in gray background. B, schematic representation of SMC2 promoter mutant variants. C, DLD1 (left) or HCT116 (right) cell lines were transfected with constructs above. Luciferase activity was normalized to Renilla activity (RLU, relative luciferase units); a representative result is shown out of at least three independent experiments. D, DLD-1 (left) or HCT116 (right) cell lines were co-transfected with Δ3 fragment mutational combinations and expression vectors for β-catenin, TCF4-VP16 (constitutively active form of TCF4), or the empty vector pcDNA3 (pcDNA); a representative result is shown out of at least three independent experiments (*, p < 0.05; **, p < 0.01; ***, p < 0.001).