Fig. 2

her9 floor plate expression requires Nodal but not Notch signaling. A: Mixed wild-type and Tg[hsp70:XdnSu(H)myc] expressing embryos heat-shocked at shield stage and then probed for her9 expression at late gastrulation. All embryos express her9 apparently normally. B: Whole-mount, dorsal view, of embryo treated with DAPT at shield stage shows her9 expression in the midline (arrowhead) at 80% epiboly (8.5 hpf). C: Whole-mount, dorsal view, of a cyc embryo probed for her9 at 80% epiboly. her9 is expressed in presumptive hypochord precursors (filled arrowhead), but expression in presumptive floor plate precursors is absent (open arrowhead). D: Transverse section at the 1-somite stage of wild-type embryo showing expression in the floor plate (arrowhead), hypochord precursors (arrow) and neural plate cells (asterisk). E: cyc mutant embryos do not express her9 in the floor plate (open arrowhead), but hypochord (arrow) and neural plate (asterisk) expression appears normal. Scale bar = 200 µm in A; 80 µm in B,C; 20 µm in D,E.