Fig. 4. Restoration of endoderm rescues arch cartilage formation in cas embryos. (A) At blastula stage, wild-type cells expressing Tar* were transplanted to a cas host. (B) Side view of the head region at 30 hpf. Grafted cells (green) have differentiated into endodermal derivatives, here pharyngeal endoderm. The arrow indicates a forming pouch. (C) These pouches restored by grafted cells (black nuclei) were stained with the Zn5 antibody (brown). (D,E) At 4 days, grafted cas embryos (E) but not controls (D) develop arch cartilage elements revealed by Alcian Blue staining. Anterior to the left. (F) Horizontal section of a grafted cas embryo showing the differentiation of cartilage elements (blue) lined by endodermal pouches derived from transplanted cells (brown). Anterior to the top. (G) Close-up of the region containing grafted cells and rescued cartilage. (H,I) 30 hpf grafted cas embryos rescues dlx2 expression in posterior cranial neural crest cells (H, dorsal view, anterior left). (I) Cross section (indicated in H) showing that wild-type transplanted cells (brown) abut the cluster of dlx2-positive neural crest cells (blue). Note the absence of dlx2 expression on the control ungrafted side of the embryo. Dorsal to the top. b, branchial arch; h, hyoid; m, mandibular; no, notochord; nt, neural tube.

Return to article