FIG. 3.

Foxd4 mediates some of the ectopic induction of Sox11, Gmnn and Zic2. The percentage of embryos in which an ectopic patch of gene expression (Sox11, Gmnn, Zic2) was observed after injection of Sia (blue bars) or Twn (green bars) mRNA in a ventral epidermal lineage in which Foxd4 translation was knocked-down (FoxMO). Sox11 induction by Sia and Twn was dramatically reduced in the absence of Foxd4. Gmnn and Zic2 induction by Sia was more strongly affected by the absence of Foxd4 than was their induction by Twn (***,p < 0.001;**, p < 0.01;*, p < 0.05). The number of embryos analyzed is shown over each bar. Examples of ectopic ventral expression of Sox11, Gmnn and Zic2 in response to injection of Twn mRNA in the presence of Foxd4 MOs. Black arrows point to the endogenous expression domains of the genes on the dorsal side. In most cases, there was no detectable Sox11 expression at the site of Twn expression (pink nuclei without purple reaction product; inset). For Gmnn and Zic2, some embryos showed no induction in the absence of Foxd4 (Gmnn left embryo; pink nuclei without purple reaction product; inset), whereas in others there was robust induction despite the knock-down of Foxd4 (Gmnn, right embryo and Zic2; pink nuclei surrounded by purple reaction product; insets). All embryos are oriented with animal pole to left and vegetal pole to right.