Fig. 3

Shh Compensates for the Loss of Axial Mesoderm in the Formation of Pancreatic Endocrine Cells

(A–C) Ventral confocal images of Tg(ins:GFP) (green) and Tg(sox17:DsRed)^s903 (red) expression, comparing wild-type (A), flh mutants (B), and shh-overexpressing flh mutants (C) at 18 hpf. (C) At 18 hpf, Tg(ins:GFP)-expressing cells were rescued in shh-overexpressing flh mutants and scattered within the endodermal sheet (red). Most endodermal cells failed to converge following shh overexpression, leading to the presence of gaps (asterisks) within the endodermal sheet.

(D–I) Lateral (D–F) and dorsal (G–I) views of Tg(ins:GFP) embryos comparing wild-type (D and G), flh mutants (E and H), and shh-overexpressing flh mutants (F and I) at 24 hpf. (D and G) Wild-type embryos show one cluster of Tg(ins:GFP)-expressing cells (arrow). (E and H) Tg(ins:GFP) expression is completely missing in flh mutants. (F and I) shh-overexpressing flh mutants show rescue of Tg(ins:GFP) expression (arrow).

(J–O) Confocal projections of pancreatic endocrine cells comparing wild-type (J and M), flh mutants (K and N), and shh-overexpressing flh mutants (L and O) at 48 (J–L) and 60 (M–O) hpf. Tg(ins:GFP) embryos were stained for GFP (green), Somatostatin (blue), and Glucagon (red). flh mutants show dramatically reduced pancreatic endocrine cells at 48 (K) and 60 (N) hpf, compared to wild-type (J and M). Tg(ins:GFP) and Somatostatin expression were rescued at 48 hpf (L), and Glucagon expression was also detectable at 60 hpf (O) in shh-overexpressing flh mutants.