Fig. 6. Expression of Nkx6.2 in the Pdx1⁺ domain restores insulin expression in Nkx6.1 mutant embryos. (A-F) Immunofluorescence detection of insulin (Ins, green) and glucagon (Glc, red). (B,E) Nkx6.1^-/- embryos have reduced insulin but normal glucagon cell numbers at E14.5 (B) and E18.5 (E) compared to wild type (A,D). (C,F) Expression of the Pdx1-Nkx6.2 transgene in Nkx6.1^-/- embryos restores the formation of insulin⁺ cells at E14.5 (C) and restores normal islet morphology and size at E18.5 (F). (G) Morphometric quantification of the insulin⁺ area over total pancreatic area in E18.5 embryos reveals an average threefold reduction of insulin⁺ area in Nkx6.1^-/- (n=5) compared to wild-type mice (n=5). The Pdx1-Nkx6.2 transgene restores the insulin⁺ area in Nkx6.1^-/- mutants to wild-type values in two embryos, whereas three embryos showed partial or no rescue (n=5). (Compare with Fig. 4.) Scale bar: 50 µm.