Figure 5

Expression of Pdx1 , Pax6 and iAPP in pancreata of wild type and Nkx2.2^-/-Arx^-a newborns. (A) In wild type pancreata, a subpopulation of delta-cells expresses low levels of Pdx1 (Arrow) while the bulk does not. (B, C) Wild type delta-cells express Pax6 and iAPP. (D, inset) Notably, in Nkx2.2^-/-Arx^- mice almost all somatostatin⁺ cells display low levels of Pdx1. (E, F, insets) Nkx2.2^-/-Arx^- somatostatin⁺ cells are immunoreactive for iAPP and low levels of Pax6. (G) Wild type epsilon-cells do not express Pdx1. (H, I) Pax6 or iAPP can be detected in a subset of wild type ghrelin⁺ cells (Arrows); a few ghrelin⁺ cells are negative for Pax6 or iAPP (Arrowheads). (J, K) In Nkx2.2^-/-Arx^- pancreata, the majority of ghrelin⁺ cells are found positive for low levels of Pdx1 and Pax6; scattered ghrelin⁺ cells do not express Pax6 (K, Arrowhead). (L, inset) Islet amyloid polypeptide is detectable in the majority of ghrelin⁺ cells; some are negative for iAPP (Arrowhead). Pictures in D, E, J and K have been captured using a 2-fold exposure time compared to respective control images in order to allow for a clear detection of Pdx1 and Pax6 (original magnification 800×). C, F, I and L are counterstained with DAPI. (M-N) Confocal images of E17.5 wild type and Nkx2.2/Arx double-mutant pancreata. Similar to the expression patterns in newborns, Nkx2.2/Arx double-deficient ghrelin⁺ cells express somatostatin, Pdx1^low and iAPP at E17.5.