Figure 1
Genetic lineage tracing demonstrated transdifferentiation of α-cells to β- and δ-cells following alloxan plus caerulein. (a) Glu-mT/mG mice were injected with caerulein and alloxan as described in the Materials and Methods section. The recombination efficiency in α-cells was 0.62+/−0.047 (S.E.M.), calculated as the number of α-cells expressing eGFP/α-cells expressing eGFP(green) plus mT (red). (b and c) Representative low-power photomicrographs of islets from mice killed at days 20 and 38, respectively, showing transdifferentiated β- (blue) and δ-cells (white). (d–h) High-power views of the regions from b and c showing lineage-marked cells expressing insulin (d and h), somatostatin (f and g) or both (e). (i) Quantification of β- and δ- cell transdifferentiation from α-cells. Note that no eGFP-positive cells expressing somatostatin were detected after alloxan alone. (j) Quantification of the frequency of islet cell types during alloxan alone or alloxan+caerulein at days 20 and 38. For the day 20 time point, 317 cells islet cells were quantified in the alloxan alone condition and 605 cells were quantified in the alloxan plus caerulein condition. For the day 38 time point, 309 cells islet cells were quantified in the alloxan alone condition and 478 cells were quantified in the alloxan plus caerulein condition. Error bars are S.E.M. Scale bar for c–g=10 μm
