Fig. 2.

Early Bmi1⁺ lineage is present only in differentiated cells. (A–D) Bmi1 is expressed in acinar cells (amylase⁺), glucagon⁺ cells (white arrowhead), and endothelial cells (PECAM⁺) (white arrowheads). (E–I) Bmi1 is largely absent from other cells in the islets (ChromograninA⁺ and C-peptide⁺), ducts (DBA⁺), and centroacinar cells (Sox9⁺) (white arrowheads). In A, B, G, and H E-cadherin staining was used to identify the cell boundaries. (J–K) Bmi1⁺ lineage is negative for Pdx1 and Nestin (white arrowheads). (L) Representative microscopic field of our analysis, the higher magnification inset shows an endothelial cell (PECAM⁺) and some acinar cells (amylase⁺). (M) At 5, 15, and 30 days pancreas was harvested from Bmi1^Cre-ER/+;Rosa26^FP/+ mice. All differentiated double positive cells were counted for each time point. (N and O) Representative pictures of 2 of the 100 cells analyzed at 5 days after TM treatment to show the perfect colocalization between YFP⁺ cell and amylase. E-cadherin staining was used to identify the cell boundaries. (Scale bars: 50 μm.)