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Fig. 6. Ventralization of Xenopus gastrulae by Xlr. Xenopus embryos were injected with 1.5 ng of xlr mRNA and analysed at stage 11–12, by whole mount in situ hybridization. In all cases embryos are viewed from the vegetal pole and the dorsal axis is uppermost. (A) Uninjected embryo showing that not1 expression is localized to the dorsal midline (the notochord), extending anteriorly from the blastopore lip. (B) xlr injected embryo showing that not1 expression is retained, but is confined to the blastopore lip. (C) Uninjected embryo showing that myf5 expression is localized to dorsal-lateral mesoderm (somites) and is absent from the dorsal midline. (D) xlr injected embryo showing that myf5 expression expands into the dorsal midline of xlr injected embryos. As a consequence, and in contrast to control embryos, some dorsal midline cells will express both not1 and myf5. (E) Uninjected embryo showing that wnt8 expression is localized to lateral and ventral mesoderm. (F) xlr injected embryo showing a dorsal shift in wnt8 expression, although it is not expressed in the dorsal midline, and a reduction in ventral expression. |
