Fig. 2. PDGFA,C,D mRNA expression in st. 8 and 10 embryos. (A,B) PDGFA is strongly expressed in caudal neural folds at st. 8. (C-E) By st. 10, PDGFA is expressed in midbrain- and trunk-level ectoderm. (F-I) PDGFC is in presumptive midbrain-level ectoderm at st. 8-10. (J) In the trunk at st. 10, PDGFC is in somites, intermediate and lateral mesoderm. (K,L) PDGFD is strong in neural folds at st. 8, and adjacent ectoderm to lesser extent. (M-O) At st.10, PDGFD is in midbrain and trunk dorsal neural tube. (N') Magnification of ectoderm and neural crest. (N'') Magnification of dorsal neural tube. PDGFD is in migrating neural crest but absent from midbrain-level ectoderm. Broken white lines in whole mounts (A,C,F,H,K,M) indicate level of section (B,D,E,G,I,J,L,N,O). ECTO, ectoderm; MES, mesenchyme; NC, neural crest; NF, neural folds; NT, neural tube; S, somite.