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Fig. 2 pdgfr?2 expression in the developing zebrafish.
In situ hybridization of embryos at 20 hpf (A) and 24 hpf (B) using an anti-sense probe against fli1a or pdgfr?2. pdgfr?2 was expressed in the floorplate (arrow) and the hypochord (arrowhead) at 20 hpf. fli1a is known to be expressed in the tail vasculature. Floorplate expression of pdgfr?2 diminished by 24 hpf while expression in the hypochord persisted and spread ventrally in association with the dorsal aorta and posterior cardinal vein (B). Cross section analysis further indicated pdgfr?2 expression in the hypochord (arrowhead), floorplate (arrow) and ventral somite boundary (brackets). cloche mutant embryos showed normal expression of pdgfr?2 indicating that pdgfr?2 was not expressed in endothelial cells of the dorsal aorta or posterior cardinal vein (D). Transmission electron micrograph images of a longitudinal section through the ISVs (E). Mural cells surrounding the endothelial cells of the ISVs were absent at 72 hpf. Notochord (nc), blood cell (BC).