Fig. 4

Fig. 4 Placode development in msxBCE morphants. (A, D) foxe4 expression at 14 hpf in a control embryo (A) and msxBCE morphant (D). (B, E) Lens and nasal pit (np) at 28 hpf in a control embryo (B) and msxBCE morphant (E). (C, F) NCAM as revealed by zn12 antibody staining in trigeminal ganglia (tg) at 24 hpf in a control embryo (C) and msxBCE morphant (F). (G, L) pax8 expression at 10 hpf in a control embryo (G) and msxBCE morphant (L). The prospective otic placode (op) is indicated. (H, I, M, N) pax2a expression at 12 hpf in a wild-type control (H), msxBCE morphant (M), a b380/b380 mutant (I), and a b380/b380 mutant injected with msxBCE-MO (N). The otic placode domain (op) or the corresponding region in the b380/b380 mutant (asterisk) is indicated. Dilute probes for krox20 and myoD were included to help identify b380/b380 mutant embryos (by virtue of their fused somites) and to visualize the hindbrain. (J, K, O, P) Pax2 antibody staining of otic placode in 12 hpf control (J), 14 hpf control (K), 12 hpf msxBCE morphant (O) and 14 hpf msxBCE morphant (P). Numerous pax2a-expressing cells have failed to converge into the otic placode by 14 hpf in the msxBCE morphant (asterisks). (Q, U) Expression of pax5 in the otic vesicle at 24 hpf in a control embryo (Q) and msxBCE morphant (U). (R, V) Expression of otx1 in the otic vesicle at 24 hpf in a control embryo (R) and msxBCE morphant (V). (S, W) msxC expression in the otic vesicle at 72 hpf in a control embryo (S) and msxBCE morphant (W). The edges of the otic vesicle are outlined. Although morpholino injection impairs accumulation of mature mRNA, msxC transcripts can still be detected by prolonging the enzymatic reaction following in situ hybridization. Positions of the anterior crista (ac), lateral crista (lc) and posterior cristae (pc) are indicated. (T, X) Dorsal view of otic vesicle at 75 hpf in a control embryo (T) and msxBCE morphant (X). Semicircular canals (ssc) are indicated. Images show dorsal views with anterior to the top (A, D, H, I, M, N) and medial to the right (J, K, O, P, Tm, X), lateral views with dorsal to the top and anterior to the left (B, C, E, F, Q–S, U–W) or lateral views with dorsal to the right and anterior to the top (G, L). Scale bar, 50 μm.