Fig. 7. Misexpression of Ci-ephrin-Ad in the endoderm activates mesoderm markers and represses endoderm markers. A FoxD enhancer was used to drive Ci-ephrin-Ad throughout the vegetal hemisphere at the 16-cell stage. (A-D) Ectopic expression of A7.6 group genes in the anterior endoderm (arrows) is observed in embryos misexpressing Ci-ephrin-Ad. The average number of endoderm cells misexpressing the mesoderm marker is shown. FGF8 appears to be most responsive to misexpression of Ci-ephrin-Ad; the others show an average of one or fewer ectopic expressing cell. (E) The endoderm marker TTF-1 is variably lost in the endoderm where Ci-ephrin-Ad is misexpressed, suggesting a partial transformation of endoderm to mesoderm fate.