
Fig. 1. Expression of genes downstream of ß-catenin in Ciona savignyi embryos. (A-E) Lineage of endodermal cells at the 16-cell stage (A), 32-cell stage (B), 64-cell stage (C), 110-cell stage (D) and tailbud stage (E). A-D, vegetal view; E, lateral view. Blastomeres shown by orange color are presumptive endodermal cells, while those in yellow are primordial endodermal cells whose fates are restricted to endoderm. (F-J) The expression of Cs-lhx3, (K-O) Cs-otx and (P-T) Cs-ttf1 gene, revealed by whole-mount in situ hybridization at the 16-cell stage (F,K,P), the 32-cell stage (G,L,Q), the 64-cell stage (H,M,R), the 110-cell stage (I,N,S) and the tailbud stage (J,O,T). Early embryos up to the 110-cell stage are viewed from the vegetal pole; anterior is upwards, posterior is downwards. The tailbud embryos in J and O are side views; T is a dorsal view. In ascidians, in situ signals for zygotic gene expression are first detected in nuclei of embryonic cells. Scale bar: 100 µm.