Fig. 3. Overexpression of eomes induces secondary axes. (A-C) Animal pole views. (D,F) Dorsal views with anterior to the left. (A) Embryo injected with myc-eomes. There is a thickened region (arrow) opposite the native shield (arrowhead). (B) Animal-pole view at shield stage of a live embryo injected with myc-eomes and GFP. Composite of white light and fluorescent images with GFP-expressing cells in green (arrow) opposite the native shield (arrowhead). (C) Live image of embryo in B at 1 dpf. Two heads are visible: the eyes from one axis are indicated by arrowheads and the eye from the second axis is indicated by arrow. (D) Embryo injected with myc-eomes and stained for fkd7 (black) has two axes side by side at 26 hpf. Arrows indicate the level of the section shown in E. (E) Section of embryo in D, dorsal is to the top. Two neural tubes are visible (arrowheads) and both stain with fkd7 (blue/purple staining). The eye is marked e. In addition to secondary axes, two other phenotypes were seen in eomes-overexpressing embryos. Embryos with bifurcated notochords in the trunk region were observed as well as embryos that resembled the dorsalized mutants previously described (Mullins et al., 1996). (F) Wild-type control embryo at 26 hpf stained for fkd7.