Fig. 3
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Fig. 3 Separate formations and rostrocaudal identity of PP2 endoderm at 20 hpf. (A-D) Separate expression of nkx2.3 indicated the rostral (arrows) and caudal (arrowheads) bulges of PP2 endoderm identified immunohistochemically with the anti-Kaede antibody. (E-J) Expression of tbx1 (E-H) and fgf3 (E,F,I,J) was detected in rostral (arrows) and caudal (arrowheads) bulges of PP2, showing early specification of the rostrocaudal polarity of PP2. (K) According to fate analysis and molecular profiles, the rostral and the caudal bulges of the future PP2 are distinctly defined as R2 (red, arrow) and C2 (green, arrowhead), respectively. Whereas cells of the intermediate region (gray) contribute to the caudal region, fgf3, a caudal marker, is not expressed in these cells at 20 hpf. A, anterior; D, dorsal; P, posterior; PP1, the first pharyngeal pouch; V, ventral. Scale bar: 20 μm. Four embryos were analyzed for nkx2.3 expression and three embryos for tbx1 and fgf3 expression.