Fig. 7. Stage 32 XHas2-Mo and XCD44-Mo injected embryos analyzed for XGremlin expression by whole-mount in situ hybridization. (A) Lateral view of the control side of two embryos, showing NCC migration pathways. (A') Lateral view of the injected side, revealed by Red-gal staining, of the embryos shown in A: no defined NCC migration pathways are recognizable. (B) Higher magnification of one of the embryo showed in A. (B') Injected side of the embryo shown in B; NCCs are still present but they do not follow their normal migration routes. (C) Longitudinal section of an XHas2-Mo injected embryo: trunk NCCs appear dispersed along the somite external aspect (injected side, red arrowheads) instead of migrating along the intersomitic boundaries (control side, yellow arrowheads). (D,D') Double-labelling of stage 32 embryo for XGremlin (blue) and 12/101 muscle-specific antigen (orange), whereas red staining reveals the injected side of the embryo. From the comparison of the control (D) and the injected sides (D'), it seems that the impairment of trunk NCC migration parallels the reduction and developmental alterations of somites. (E,E') Stage 32 XCD44-Mo injected embryos analyzed for XGremlin expression. No differences in NCC migration are discernible between the control side (E) and the injected side (E') of the embryo.