RT Journal Article SR Electronic T1 Constitutive Transcriptional Activation by a β-Catenin-Tcf Complex in APC−/− Colon Carcinoma JF Science JO Science FD American Association for the Advancement of Science SP 1784 OP 1787 DO 10.1126/science.275.5307.1784 VO 275 IS 5307 A1 Korinek, Vladimir A1 Barker, Nick A1 Morin, Patrice J. A1 van Wichen, Dick A1 de Weger, Roel A1 Kinzler, Kenneth W. A1 Vogelstein, Bert A1 Clevers, Hans YR 1997 UL http://science.sciencemag.org/content/275/5307/1784.abstract AB The adenomatous polyposis coli (APC) tumor suppressor protein binds to β-catenin, a protein recently shown to interact with Tcf and Lef transcription factors. The gene encoding hTcf-4, a Tcf family member that is expressed in colonic epithelium, was cloned and characterized. hTcf-4 transactivates transcription only when associated with β-catenin. Nuclei of APC−/− colon carcinoma cells were found to contain a stable β-catenin-hTcf-4 complex that was constitutively active, as measured by transcription of a Tcf reporter gene. Reintroduction of APC removed β-catenin from hTcf-4 and abrogated the transcriptional transactivation. Constitutive transcription of Tcf target genes, caused by loss of APC function, may be a crucial event in the early transformation of colonic epithelium.