Fig. 6. Analysis of hypaxial cell migration in XHas2-Mo and XCD44-Mo injected embryos. (A,A') Lateral view of control (A) and injected (A') side of an XHas2-Mo injected embryo (mild phenotype) at stage 37 showing the relative position of differentiating hypaxial muscle cells, as highlighted by 12/101 antibody staining (arrows). (B,B') Transversally sectioned XHas2-Mo injected embryo hybridized with CA and coloured with Hoechst to visualize the nuclei, in which it is evident that the somite structure is altered and the ventrolateral migration of hypaxial muscle cells is impaired (red arrow). (C) Lateral view of the control side of a XHas2-Mo-injected embryo analyzed for XPax3 expression by in situ hybridization at stage 37 highlighting hypaxial muscle cells migrating ventrally (arrow). (C') Injected side of the embryo shown in C, in which hypaxial muscle cells are blocked at the ventral aspect of somites (red arrow). (D,D') Stage 37 XCD44-Mo injected embryos immunostained with the 12/101 antibody. Although the trunk musculature appears unaffected by XCD44 loss, migration of hypaxial cells is greatly reduced. (D) Control side of the embryo; (D') injected side. (E-G) Ventral views of stage 43 embryos immunostained with the 12/101 antibody that show the final position of the ventral body wall musculature in uninjected (E), XCD44-Mo injected embryo (F) and XHas2-Mo injected embryo (G). The side of injection is visualized by X-gal staining in blue and indicated by the arrow. (E'-G') Lateral views of the same embryos shown in E-G, respectively.