Fig. S7

Sox3 overexpression is able to inhibit the ectopic expression of chd induced by a range and combination of upstream factors. Embryos were injected with 50 pg of various RNAs (indicated above each panel) alone or combination and analysed for chd expression at 4.5 hpf (A). Injection of boz, fgf3, or boz combined with fgf3, caused expansion of chd expression into the animal hemisphere of embryos (Ab–d). Injection of the additional up-stream factors, S37A (constitutive active β-catenin) and sqt strongly induced expansion of chd throughout the entire animal hemisphere (Ae). However, co-injected with sox3 (B) led to reduced expansion or negative patches in the expansion of chd expression no matter which other factors were injected. Although the combination of all factors still gave strongest extopic expression, co-injection of sox3 was still able to generate chd negative patches (Be). Lateral view and dorsal is to the right in upper panels, viewed from animal pole in lower panels. The proportion of embryos exhibiting these phenotypes is shown at the bottom right of each panel.