Fig. 5

Maintenance of dkk1 expression depends on bozozok/dharma and Nodal signals. (A) dkk1 expression in dorsal marginal blastoderm and dorsal YSL was detected at the sphere stage in both boz^m168 heterozygous (left) and homozygous (right) embryos. dkk1 expression in the embryonic shield was observed at the shield stage in boz^m168 heterozygous embryos (left), but could not be detected in boz^m168 homozygous embryos (right). When 5 pg of dharma RNA was injected to one blastomere (located in the lateral position) of 8-cell stage embryos, about a half of the dharma RNA-injected embryos exhibited expansion of dkk1 expression in the dorsal side, and the rest of them exhibited an ectopic expression of dkk1 at the shield stage (lower panel). Animal pole views, dorsal to the right. (B) dkk1 expression was normal at the sphere stage in both sqt^cz35 heterozygous (left) and homozygous (right) embryos. dkk1 expression in the embryonic shield was observed at the shield stage in sqt^cz35 heterozygous embryos (left), but could not be detected in sqt^cz35 homozygous embryos (right).