Fig. 7

Overexpression of dkk1 promotes anterior neuroectoderm development in the absence of dorso-anterior mesendoderm. (A) Embryos injected with 5 pg of antivin (atv) RNA lack most of mesoderm and endoderm except tail region, but contained a cyclopic eye (a). Embryos coinjected with 5 pg of atv and 20 pg of dkk1 RNA displayed enlarged head structures (b) with an enlarged cyclopic eye (c) which expresses six3 in a higher level (e), compared to an eye in the atv RNA-injected embryos (d). (B) Expression of gsc in the embryonic shield was not detected in either the atv RNA-injected embryos (a) or the atv and dkk1 RNA-injected embryos (b), compared to uninjected shield-stage embryos (c). Animal pole views, dorsal to the right. However, expression of six3 at 9 hpf was expanded in the atv and dkk1 RNA-injected embryos (e, g), compared to the atv RNA-injected embryos (d, f). (d, e) Lateral views, dorsal to the right. (f, g) Dorso-anterior views.