Figure 5

chch -inhibited cells leave the epiblast and enter the germ ring and become mesoderm. (A) A schematic representation of the transplantation scheme. Cells from sphere stage LacZ, chch-EnR mRNA or chch-ATGMO injected donors were transplanted to the animal hemisphere of 30% epiboly (late blastula) wild-type embryos. Embryos were photographed at 40% epiboly (B, E, H, K), at the start of gastrulation (shield) (C, F, I, L) and after 24 hpf (D, G, J, M). As expected, LacZ cells remain within the ectoderm and take on ectodermal fates at 24 hpf (B-D). In contrast, chch inhibited cells often migrate from the presumptive ectoderm to the germ ring (E-G, K-M). These cells are often later found in the somites (G). The abnormal movement of chch-EnR cells into the germ ring is rescue by coinjection of chch mRNA (H-J). The images in each row are of the same embryo.