Fig. 4. Transient Nodal signalling autonomously commits cells to an endodermal fate. One single activated cell (white arrowhead) transplanted to the animal pole of a blastula host (A) expresses sox17 during gastrulation (arrowhead in B) and become endodermal derivatives at 24 hpf (arrow in C). Co-injection of Tar* and FASTSID at the 2-cell stage (D) results in the cells that were transplanted to the animal pole being incorporated into the eye and the brain (E). By contrast, delayed injection of FASTSID (F) results in cells grafted to the animal pole adopting an endodermal fate (G).
