Fig. 4. Xenopus Galntl-1 loss-of-function phenotype. (A) Stage 40 uninjected control embryo and embryo injected radially with the xGalntl-1-specific morpholinos at the 2- to 4-cell stage. Numbered lines indicate the positions of the paraffin sections shown on the right that reveal a reduction of neural tissue in the morpholino-injected embryos. (B) Uninjected control embryo and embryos microinjected with xGalntl-1 morpholinos stained with the notochord-specific antibody MZ15 at stage 40 (left) and analysed by in situ hybridisation for slug expression at stage 30. The morpholino-injected embryos display defects in the anterior notochord and reduced anterior expression of slug. (C) Whole-mount in situ hybridisation for slug of stage 15 embryos after radial microinjection of the xGalntl-1 morpholinos at the 2- to 4-cell stage, and stage 13 embryo stained for msx1 after single injections of the xGalntl-1 morpholinos into a dorsal-animal blastomere at the 8-cell stage together with lacZ mRNA. (D) RT-PCR analysis of stage 20 dorsal marginal zone explants from uninjected embryos or embryos microinjected with xGalntl-1 morpholinos alone or together with xGalntl-1 mRNA (20 pg). The expression of otx2 and six3 (forebrain) as well as of snail (neural crest) was inhibited by the xGalntl-1 morpholinos, whereas the expression of dlx5 (epidermis), xvent2 (ventral mesoderm) and xbra (mesoderm) was unaffected.