Figure 1—figure supplement 1.

(A) Specific deletion of Bcl9/9l and Pygo1/2 in the intestinal epithelium was achieved by introducing a tamoxifen-dependent vil-Cre-ERt2 driver. Mice were injected with tamoxifen at four weeks of age and analyzed at different time-points thereafter. Deletion was monitored by quantitative PCR (qPCR) on genomic DNA. Gene deletion was stable over at least 23 weeks, indicating that the stem cell compartment was successfully hit, and that no selective disadvantage of mutant compared to wild-type cells occurred. (B) Bcl9/9l and Pygo1/2 deletion was also monitored via quantitative reverse-transcriptase (RT)-PCR both in colon (left panel) and in duodenal cells (right panel). (C) Histological analysis was performed on the small intestine and the colon. Compared to control (CTRL) littermates, conditional Pygo1/2-KO mutants displayed normal intestinal architecture. We detected all differentiated cell types, including the secretory lineages such as goblet cells (alcian blue positive), paneth cells (lysozyme positive), and enteroendocrine cells (synaptophysin positive). (D) The Ki67+ fraction was calculated by normalizing the length of the proliferative compartment by the relative crypt villus length, and 10–15 crypts were scored for each biological replicate considering at least three different mice per genotype. (E) Quantification of villus length in the small intestine (left) and crypts depth in the colon (right) in Pygo1/2 conditional mutant compared to control littermates. three mice per genotype were considered.