Fig. 9. Gastrulation and formation of the endomesoderm requires downregulation of TCF. (A) Scheme of the experiment. (B-R) Embryos were injected at the egg stage and treated continuously with Dexamethasone (DXM) starting either at the egg cell stage (C,G,K,P),or at the hatching Blastula (D,H,L,Q) or the early mesenchyme Blastula (vemB) stage (E,I,N,R). The morphology of the embryos is documented in B-E. (F-R) In situ hybridization with the probes indicated on the left. (B,F,J,O) Control embryos. vv, vegetal pole view.