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Fig. 3. Whole-mount in situ hybridisation showing that XASH3 promotes neuronal differentiation in noggin caps, but not until the tadpole stage. Xenopus embryos were injected bilaterally at the 2-cell stage, with noggin (A,D) or noggin plus XASH3 RNA (B,E), animal caps were dissected at blastula stage, cultured either until the neural plate stage (stage 16; A,B) or the tadpole stage (stage 27; D,E) and hybridised with a probe for N-tubulin. (C,F) Control embryos at stage 16 and stage 27, respectively. Note that noggin alone does not promote the formation of N-tubulin-expressing cells either at stage 16 (A) or at stage 27 (D). Noggin plus XASH3-injected animal caps undergo neuronal differentiation, but only if cultured until stage 27 (E), not at stage 16 (B). In contrast, N- tubulin is expressed abundantly at stage 16 (C) in the embryo, suggesting that noggin plus XASH3-injected animal caps need additional signals in order for neuronal differentiation to occur at the neural plate stage. |
