DKK1, a negative regulator of Wnt signaling, is a target of the β -catenin/TCF pathway

Wnt signaling plays an important role in embryonic development and tumorigenesis. These biological effects are exerted by activation of the β-catenin/TCF transcription complex and consequent regulation of a set of downstream genes. TCF-binding elements have been found in the promoter regions of many TCF target genes and characterized by a highly conserved consensus sequence. Utilizing this consensus sequence, we performed an in silico screening for new TCF target genes. Through computational screening and subsequent experimental analysis, we identified a novel TCF target gene, DKK1, which has been shown to be a potent inhibitor of Wnt signaling. Our finding suggests the existence of a novel feedback loop in Wnt signaling.