Figure 1

(A) Schematic representation of the Wnt/?-catenin transcriptional complex, with emphasis on the so-called ?chain of adaptors? components, ?-catenin, BCL9/9L and PYGO; Wnt Responsive Element (WRE). The homology domains 1?3 (HD1-3) of BCL9/9L are shown. (B) Epithelial-specific Pygo1/2 deletion (via vil-Cre-ERt2; Pygo1/2-KO) does not lead to any obvious histological or functional defect, neither in the small intestine nor in the colon as seen by hematoxylin and eosin staining (left panels). The proliferative compartment, detected via Ki67 (right panels), seems also unaffected (also refer to the count in Figure 1?figure supplement 1D?E). (C) Quantitative RT-PCR detecting Lgr5 mRNA extracted from colonic epithelium of control (black), Bcl9/9l (blue) or Pygo1/2 (red) conditional mutants (KO). (D) 6?8 week-old male mice were treated with five tamoxifen (Tam) injections (i.p., 1 mg/day) for five consecutive days. 10 days later mice were treated with 2.5% dextran sodium sulfate (DSS) ad libitum in drinking water for 9 days. While 17% of control mice (N = 30) were severely affected or died due to the DSS treatment (red lines), 65% of conditional Bcl9/9l-KO (N = 34) mice performed poorly in this test. Deletion of Bcl9/9l increased significantly the death rate after DSS treatment (p-value=0.00013 in Fisher's Exact Test). No difference between Pygo1/2-KO and control mice could be measured: 27% of control mice (N = 22) and 25% of Pygo1/2-KO (N = 24) were affected upon DSS treatment (p-value=0.5626 in Fisher's Exact Test). (E) 6?8 week-old female mice were exposed to a single dose of the carcinogenic agent azoxymethane (AOM), followed by 7 days of DSS administration in the drinking water. This regimen results in the emergence of dysplastic adenomas that are collected for RNA extraction and analysis of the indicated targets via RT-PCR: Wnt target genes and genes expressed during epithelial-to-mesenchymal transition (EMT), associated with cancer metastasis.