Figure 8

Neurog3⁺ cells arise from Muc1⁺ ductal cells during embryogenesis. To detect the short-term differentiation potential of Muc1⁺ cells, Muc1^IC2/IC2; Rosa26EYFP^/+ embryos were labeled by TM administration to pregnant dams at E13.75 (A, C) or E14.75 (B, D), and harvested ~12 hours later for immunofluorescence analysis (n = 2 for each timepoint). (A-B) Short-term labeling of Muc1⁺ cells (green) reveals their presence within the E-cadherin⁺ ductal network (blue, open arrowheads), as well as their contribution to Neurog3⁺ cells (red, closed arrowheads). (C-D) Similar analysis of islet hormone expression indicates that Muc1^IC2 labeling (green, open arrowheads) is excluded from insulin⁺ (red) and glucagon⁺ cells (white), confirming that these cells derive from Muc1⁺ progenitors but do not themselves express Muc1. Scale bars: 50 μm in A-B and 100 μm in C-D.