Fig. 5. Defects of ß-cell maturation in Gdf11^-/- mice at E17.5. (A-B) Accumulation of cells expressing NKX6.1 (brown nuclei) in Gdf11^-/- mice. (C) Quantification of NKX6.1⁺ nuclei per mm² tissue. Data here and in panels F and K are shown as the average measurements ± standard error of the mean (n=3 mice per genotype). Asterisk indicates that the measured difference in NKX6.1⁺ nuclei in Gdf11^-/- compared with Gdf11^+/+ mice is significant at P<0.05. (D,E) Accumulation of cells expressing NKX2.2 (brown nuclei) in Gdf11^-/- mice. (F) Quantification of NKX2.2⁺ nuclei per mm² tissue. The asterisk indicates that the measured difference in NKX2.2⁺ nuclei in Gdf11^-/- compared with Gdf11^+/+ mice is significant, at P<0.05. (G,H) NKX6.1 positive cells retain their neuroendocrine identity in Gdf11^-/- mice at E17.5. NKX6.1 (red nuclear staining) is co-expressed with synaptophysin (green cytoplasmic staining) in both wild-type and null animals. (I,J) Absence of insulin expression (green) in a subset of NKX6.1⁺ cells (red nuclear staining) in Gdf11^-/- mice at E17.5. (K) Quantification of the percentage of NKX6.1⁺ cells lacking immunostainable insulin in wild-type and Gdf11^-/- mice. The asterisk indicates that the difference in values is significant, at P<0.05. (L,M) Absence of glucagon expression (green) in NKX6.1⁺ cells (red nuclear staining) in wild-type and Gdf11^-/- mice at E17.5. (N,O) Normal numbers of ghrelin⁺ cells in wild-type and Gdf11^-/- mice at E17.5 (red cytoplasmic staining). Panel N and O insets demonstrate cytoplasmic localization of ghrelin.