Transcription activation by E1A-HD2 fusion proteins. A. Diagram showing the proteins that recruit the E1A-HD2 fusion protein to Tcf sites. B. Diagram showing the fusion proteins used in the reporter assay. CR1-4: E1A conserved regions 1 to 4  C. Luciferase assays in SW480 cells transfected with a Tcf-E2 reporter and E1A expression vectors. D. Luciferase assays in HeLa cells transfected with a Tcf-E2 reporter and vectors expressing E1A and N-β-catenin. The activity is expressed in arbitrary units relative to the reporter alone in C, and the reporter plus N-β-catenin in D.