Fig. 4

Fgf signaling is necessary within the pharyngeal endoderm for dlb expression, but is not required for 5HT expression in taste buds. Experimental conditions are indicated in the top right-hand corner, embryonic stage and scale bar are in the bottom left-hand corner and marker expression is in the bottom right-hand corner. Ventral views, anterior is towards the top. Arrows indicate marker co-expression in a single cell. Scale bars: 5 μm. (A-E) Optical sections (A,C,E) (2 μm) and asymmetric confocal projections (B,D,F) through pharyngeal endodermal (Tar^*) grafted cells (in wild type) that express dlb (red) and GFP or Dnfgfr1 (green), after heatshock. dlb taste bud-related expression in the mandibular arch (m) is within the broken lines. Most GFP cells in the control graft co-express dlb (A, arrows); by contrast, most Dnfgfr1 cells are devoid of dlb expression (B, green). (G-L) Confocal projections through pharyngeal endodermal (Tar^*) grafted cells (in wild type) that express 5HT (blue) and GFP or Dnfgfr1 (green) after heatshock. Broken lines mark the palate (p).