Fig. 7

Fig. 7 Expression pattern of snail2 and no tail in wild-type and spadetail (spt^b104) mutant embryos at gastrulation. (A–C) Wild-type and (D–F) sibling spadetail embryos at 90% epiboly. (A and D) Dorsoanterior view; (B and E) dorsoposterior view; (C and F) right side views. An asterisk marks the presumptive hatching gland domain and an arrowhead indicates the marginal zone. spadetail embryos have fewer snail2-expressing cells laterally than wild type. snail2-expressing cells in the axis occupy an irregular, loose, and broader domain compared to wild type. The snail2 expression domain is also closer to the margin. This shows that a spadetail embryo is shorter than wild type and that the axial domain of snail2 expression is enlarged at gastrulation. This broadening of axial mesoderm was confirmed by examining the distribution of no tail RNA, a notochord marker (Schulte-Merker et al., 1994) in wild-type (G) and spadetail mutant (H) embryos at 80% epiboly. Anteroposterior (a–p). Scale bar, 25 μm.