The fates of the three regions of the Xenopus blastula are altered by the depletion of VegT. In normal embryos, the animal third forms epidermal and neural ectoderm, the equatorial third forms mesoderm, and the vegetal third contains the VegT protein and forms the endoderm. In VegT-depleted embryos, the animal cap forms only ventral epidermis, while the equatorial third produces epidermal and neural ectoderm. The vegetal third of these embryos produces ectoderm (both epidermal and neural) as well as mesoderm. No endoderm is produced. (After Zhang et al. 1998.)