Fig. 9. ß-catenin deletion in adult exocrine cells. (A,B) X-gal staining (blue) on sections of adult R26R;Ela-CreERT double transgenic pancreata. In the absence of tamoxifen (TM) administration (A), a low level of TM-independent acinar labeling is observed (arrow), whereas widespread acinar labeling is observed two weeks after TM administration (B). No labeling is observed in ductal elements (arrowheads). (C-E') Confocal immunofluorescence to detect ß-catenin and amylase expression. All amylase⁺ cells in the TM-untreated pancreas retain ß-catenin expression (E), whereas many ß-catenin^–/amylase⁺ cells can be found following TM treatment, including entire acini (arrowhead) comprising ß-catenin-deficient cells but exhibiting normal architecture (E').