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Figure 3. Temporal and spatial expression of Xfeb. A: A developmental profile of Xfeb expression was generated by quantitative RT-PCR using RNA from staged Xenopus embryos (top). EF-1 alpha and ODC served as loading controls (bottom). Y axes represent the relative abundance of transcripts in log scale and developmental stages are listed along the bottom. Xfeb expression begins at early gastrula stage 10 and continues throughout neurula stages. B-I: Characterization of Xfeb expression by whole mount in situ hybridization. Xfeb is expressed in hindbrain regions at stage 13 (B) and stage 17 (C). Xfeb expression overlaps extensively with zic1 expression (D; stage 17). At stage 20, Xfeb is expressed in a broad area in the midbrain and hindbrain and lateral to the neural tube (E). At stage 23, Xfeb is expressed in the midbrain and hindbrain region (F, arrowheads). The enlarged region (equivalent to box in F) shows Xfeb expression in a chevron pattern in the trunk (G). Double in situ hybridizations of stage 17 embryos with probes for Xfeb (brown) and en-2 (orange, arrowheads in H) and with probes for Xfeb (brownish purple) and wnt1 (purple, arrowheads in I) show that Xfeb is expressed in the hindbrain region up to the midbrain/hindbrain boundary, as defined by wnt1 staining. J: To confirm the relative staining patterns of en-2 and wnt1 in Xenopus, double in situ hybridization with wnt1 (purple) and en-2 (turquoise) was performed. All embryos are shown as dorsal views with the anterior ends up, except F and G, which are side views with dorsal sides up. |
