Fig. 3. Sox9-AS prevents neural fold formation. Embryos were injected in one blastomere at the two-cell stage with 10 ng of Sox9-AS (A-C) or 10 ng of Co-AS (D-F) and analyzed at stage 17. RNA encoding the lineage tracer ß-galactosidase was co-injected to identify the injected side (blue), shown on the right in all panels. (B,C) Transverse section of the embryo presented in A shows that the neural fold is missing on the injected side (blue staining) when compared with the uninjected side (arrowhead). (E,F) Transverse sections of the embryo presented in D shows that the neural fold is unaffected on the injected side (blue staining). n, notochord; s, somite. Insets in B,E depict whole embryo ß-galactosidase staining (blue) of the specimens presented in A,D, respectively. (G) Scanning electron micrograph of a Sox9-AS-injected embryo at the early neurula stage. Note the absence of the neural fold in the injected side when compared with the uninjected control side (arrowheads).
