Fig. 5.

Dorsal mesoderm-animal cap explant studies. (A) When cultured alone, wild-type ectoderm (animal cap) contained little sox9 RNA, as visualized by in situ hybridization (analysis carried out when control embryos had reached stage 17/18). (B) When cultured together with DLMZ from wild-type Xenopus embryos, sox9 RNA accumulated (in the ectodermal region). (C) By contrast, DLMZ from snail2 C2/C3 morphant embryos failed to induce sox9 RNA. (D,E) snail1 morphant DLMZ appears to be intermediate in its ability to induce sox9 expression (D), whereas twist1 morphant DLMZ retained the ability of induce sox9 expression (E). (F) qPCR analysis of sox9 RNA levels supports this general trend. For each condition, 5-15 explants were analyzed when unmanipulated embryos had reached stage 17/18. ODC RNA was used as a standard. WE, whole embryo at stage 17/18 (level set to 1); AC, animal cap/ectodermal explant; ACM, animal cap plus DLMZ from uninjected control embryo; snail2, wild-type animal cap plus snail2 morphant DLMZ; snail1, wild-type animal cap plus snail1 morphant DLMZ; twist1, wild-type animal cap plus twist1 morphant DLMZ. The results shown are representative of more than three replications. Error bars indicate s.d.