Fig. 7. Loss of Ptf1a/p48⁺ acinar precursors in the absence of ß-catenin. Confocal immunofluorescence at E13.5 detects peripheral clusters of Ptf1a⁺ cells in wild-type pancreata (A-C), presumably representing acinar precursor cells. Ptf1a⁺ cells are much more infrequent in PBKO pancreata (A'-C'), and are restricted to residual ß-catenin⁺ regions, indicating that they derive from cells in which Catnb remains undeleted.