Figure 2.

YFP fluorescence in Ptf1a^YFP/+ and Ptf1a^YFP/YFP embryos. In Ptf1a^YFP/+ embryos, YFP fluorescence can be detected in all sites of bona fide Ptf1a expression by whole mount fluorescence microscopy. Uniform YFP fluorescence is seen in the neural tube as well as in the pancreatic buds at E10.5, which expand and fuse by E12.5. At E13.5, YFP fluorescence is punctate which denotes acinar restriction. At E15.5, exocrine cells have proliferated which results in increased intensity of YFP fluorescence. In Ptf1a^YFP/YFP mice, dorsal and ventral Ptf1a expression is initiated at E10.5, but growth of the pancreatic buds is severely retarded by E11.5. Ventral YFP fluorescence is lost by E12.5, but can be observed in the DPR until E13.5. However, by E15.5 YFP fluorescence is extinguished in Ptf1a^YFP/YFP mice. Scale bars = 50 µm unless otherwise noted. Dorsal Pancreas (DP), Ventral Pancreas (VP), Dorsal Pancreatic Remnant (DPR), Ventral Pancreatic Remnant (VPR).