Fig. 4

SU5402 inhibits extension of the MFF structure formation. Embryos were exposed to 0.17% DMSO for control (A, C, E, G) or 20 μM SU5402 (B, D, F, H) from 18 hpf for 3 h. (A, B) Lateral view of embryos, anterior to the left. (a, b, c, d) HE staining of transverse sections at the level of each bar in panels A and B. While the dorsal midline (at the level of yolk extension) of control embryos consisted of wedge-shaped cells (a; bracket), SU5402-treated embryos did not have such cells at the same level (c). At the tail bud, the fin fold was seen in SU5402-treated embryos (d; bracket) but was immature compared with that in control embryos (b; bracket). (C–H) Expression patterns of dlx5a (C, D), sp9 (E, F), and fgf24 (G, H). (D) dlx5a expression was unaffected in SU5402-treated embryos. (F) Expression of sp9 was suppressed in the median fin fold after SU5402 treatment, and the expression domain was limited caudally to the cloaca level (arrowhead). Expression of fgf24 was not detectable in the tail tip of SU5402-treated embryos (H). Arrowheads in panels C–F indicate rostral border of the expression domain. Scale bars in panels A and C are 200 μm. The panel width of (a–d) is 100 μm.