Fig. 8. Functional Nodal signalling is required cell autonomously to allow Cas to change the cell fate. (A) Experimental procedure. MZoep or wild-type embryos were injected with a lineage tracer (gfp for MZoep embryos and rhodamine for wild-type embryos) alone or combined with cas RNA. By the blastula (sphere-dome stage), one mutant cell and one wild-type cell were transplanted to the margin of a wild-type host (B). During gastrulation, both mutant and wild-type cells, expressing cas or not, involute and remain close to or in contact with the YSL (C,D). The dotted line indicates the position of the margin. (E) Anterior to the left, dorsal to the top. At 24 hpf, MZoep cells hardly ever took part in endodermal derivatives (only six intestinal cells in one embryo, out of 24 embryos), whereas wild-type cells expressing cas frequently participated in the endoderm (58%, n=31; Fig. 6). Abbreviations: s, somites; y, yolk.