Fig. 4. Analysis of gene expression in embryos injected with eomes mRNA. All embryos are at the shield stage (6 hpf) and all views are from the animal pole, except (C,) which is a lateral view. In A,B,D,E,G,H the shield is to the right. Bottom right corner indicates in situ probe used, top right corner indicates the gene construct, if injected. (A) Uninjected embryo stained for gsc expression in the shield region. (B) Injection of myc-eomes induced ectopic gsc expression at the margin (arrowheads). Arrow marks region shown in lateral view in C. (C) Embryo in B after anti-Myc antibody staining (brown). Myc-labeled cells and cells ectopically expressing gsc are in different focal planes. (D) Expression of chd in an uninjected control. (E) Ectopic chd expression in an embryo injected with myc-eomes (arrowheads). (F) High-magnification view of margin of an embryo injected with myc-eomes. White outline surrounds a cell that expresses chd and Myc. (arrow). Red outline demarcates a cell expressing chd but not Myc (arrowhead). (G) Expression of flh in an uninjected control. (H) Embryo injected with myc-eomes with ectopic flh expression (arrowhead). (I) High-magnification view of embryo injected with myc-eomes. The same cells stain for flh (arrowheads) and Myc (arrow).