Figure 9

Simultaneous knock-down of Ascl1b and Neurod1 blocks the differentiation process of the precursors. Ventral views with the anterior part to the left of the pancreas of control (A,C,E,G,I) or Mo-ascl1b/Mo2-neurod1 morphants (B,D,F,H,J) analyzed by fluorescent (A-D, G-J) or visible (E-F) WISH. (A-B) Confocal projections of isl1 expression in the pancreatic islet (dotted line) and in the adjacent mesoderm (*) at 38 hpf (C-D) and of sox4b expression at 17 hpf. (E-F) ascl1b transcript expression at 13 hpf (8s). (G-H) Confocal projections of pax6b (green) and mnx1 (red) expression at 17.5 hpf showing that the pancreatic expression of pax6b and mnx1 is completely lost in the double morphants. In contrast, the expression of pax6b in the neural tube and the expression of mnx1 gene in the motoneurons and the hypochord is not perturbed. (I-J) neurod1 transcript expression at 15 hpf (12s). hpf, hours post fertilization; WISH, whole-mount in situ hybridization.