Figure 5

Notch1^ICD inhibits the activity of Ngn3. (A-H). Confocal sections of chicken embryonic pancreata 52 hours after electroporation with Ngn3 (A-D) or Ngn3 and Notch1^ICD (E-H) subjected to immunohistochemical stainings against Nkx6.1 (red) (A, E), Pax6 (red) (B, F), glucagon (red) and insulin (blue) (C, G), or MPM2 (red) (D, H). GFP was detected by its endogenous fluorescence (A-H). Inserts show higher magnification of boxed areas in the cognate panels. (I) Bar graph illustrating the quantitative analysis of MPM2/GFP double-positive cells as a percentage of total GFP-positive cells 52 hours after electroporation with the indicated expression plasmids at HH st. 13–15. Note the absence of insulin and glucagon, the presense of MPM2, and persistent Nkx6.1 expression in GFP-positive cells in the Ngn3 plus Notch1^ICD electroporated, compared to Ngn3 electroporated embryos.