Fig. 4

Fig. 4

Lack of Ncad causes neurulation defects. (A-N) Whole-mount in situ hybridization for the markers indicated in the top right-hand corner. Dorsal views with anterior towards the left in A-H; optical cross sections dorsal upwards in I-N; all paired panels compare a pac mutant (right) with a wild-type sibling (left). (O,P) Mid-hindbrain cross-sections of wild-type embryos co-transplanted with cells from two different donors, as indicated in the bottom right-hand corner; donor cells are stained in cyan or brown. (A,B) foxd3, three-somite stage; note the identical mediolateral extent of the neural plate in wild-type and pac. (C,D) sna2, five-somite stage; arrows indicate the width of neural plate delineated by sna2 stripes, larger in pac. (E,F) emx1 (blue; marking telencephalon) + lim5 (red; marking posterior diencephalon) (Toyama et al., 1995a), 10- somite stage. In F, cells in the fused part of the lim5 expression domain are located ventrally, cells in the bilateral parts dorsally. (G,H) wnt1, 26 hpf; arrows indicate fused (G) and bilateral (H) expression domains in the midbrain. (I,J) pax6 + shh; 12-somite stage; section at hindbrain level. The alar plate devoid of pax6 staining is outlined by dots. (K,L) pax7, 16-somite stage; optical section at hindbrain level. Arrow in K indicates a pax7 stripe in the interface of basal and alar plate. (M,N) pax2.1, 24 hpf; optical cross-section through midbrain-hindbrain boundary region; arrow indicates the region where basal and alar plate have morphologically separated. (O,P) Chimeric embryos, 24 hpf, cross-section at midbrain (P) and hindbrain (O) levels. Note that in P, wild-type cells (in brown) populate the basal plate, while pac^paR2.10 mutant cells (in cyan) remain alar, although both cell types had initially been transplanted to the same presumptive basal region of the host embryo.