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Fig. 4. Noggin induces a pattern of expression of XIF3 in animal caps that is similar to that found in anterior neuroectoderm but not in primary neurons. (A) Stage 22 embryo stained by in situ hybridization with a NST specific antisense RNA probe. The anterior of the embryo (ant) is at the top. (B) Noggin injected animal caps also stained with the NST specific probe at the equivalent stage to (A) lack NST expression. (C) Stage 22 embryo stained by in situ hybridization with a XIF3 specific antisense RNA probe. (D) Noggin injected animal caps at the same stage stained with the XIF3 specific probe. Arrows indicate large patches of evenly distributed XIF3 staining. However the staining does not cover the entire animal cap. (E) Control uninjected animal caps assayed at stage 22 are negative for XIF3 expression. (F) Explant of animal cap and a small piece of dorsal mesoderm that induces the formation of primary neurons and at stage 22 results in a punctate pattern of XIF3 expression. Bar in A, 0.5 mm; in B. 0.25 mm. |
