Wnt signaling plays an important role in embryonic development and 
tumorigenesis. These biological effects are exerted by activation of the 
beta-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.