Fig. 8. LvDelta expressed by mesomeres is sufficient to induce animal caps to develop mesoderm and endoderm. (A) Experimental design. To generate the host, an animal cap was isolated at the 8-cell stage. Fertilized eggs were injected with the truncated or full-length form of LvDelta mRNA and one mesomere was isolated at the 16-cell stage and transplanted to the vegetal pole of the animal cap. (B) An animal cap recombined with a mesomere expressing truncated LvDelta develops into a hollow ball of ectoderm. (C) Epifluorescence image of the larva in B demonstrates that the transplanted mesomere contributes to the epithelium. (D) An animal cap recombined with a mesomere expressing full-length LvDelta develops into a pluteus larva. (E) Epifluorescence of the larva in D shows that the transplanted mesomere contributes to the foregut, midgut and mesoderm, though some endoderm and mesoderm is not labeled with the lineage tracer. These larvae develop blastocoelar cells (F) and skeletogenic cells (G).
