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Figure 5. Effects of Xwnt8 gain-of-function on the expression of Hoxd1, Hoxa1, Hoxb1, Hoxb4, Hoxd4, Hoxc6, as well as Xbra, Xcad3, and Otx2. Embryos were injected at the one-cell stage into the animal hemisphere with 100 pg of CS2-Xwnt8 plasmid and analyzed by whole-mount in situ hybridization. Injected embryos are shown on the bottom of each panel, control embryos on the top. A: Expression of Hoxd1 is ectopically up-regulated in dorsal tissues of injected embryos; shown are stage 10 (left side of the panel) and stage 12.5 (right side of the panel) embryos, the views are dorsal with anterior to the top. B: Hoxa1 expression is up-regulated at stage 11, and the horseshoe pattern closes up in the dorsal midline of the embryo after overexpression of XWnt8 (left side of the panel); at stage 13, there is no evident alteration of expression (right side of the panel); views are vegetal with dorsal to the top. C: pCS2XWnt8 injections lead to a strong ectopic expression of Hoxb1 at both stage 11 (left side of the panel) and stage 13 (middle column of the panel); views are vegetal with dorsal to the top, except for the stage 11 injected embryo, which is seen from the lateral. Dissections of the stage 13 embryos are presented (left side of the panel); embryos were cut along the anterior-to-posterior axis, as depicted by the dotted lines in the insets on the bottom left corner. D: The expression of Hoxb4 is up-regulated at stage 11 and the horseshoe pattern closes up on the dorsal midline of the embryo after Xwnt8 gain-of-function (left side of the panel); expression is not obviously changed at stage 13 (right side of the panel); views are vegetal with dorsal to the top. E: Hoxd4 expression becomes stronger with the XWnt8 gain-of-function, shown are stages 11 (left side of the panel) and 13 (right side of the panel); views are vegetal with dorsal to the top. F: Expression of Hoxc6 is up-regulated dorsally at stage 10 (left side of the panel), and in neuroectoderm of stage 15 embryos (right side of the panel). G: Expression of Otx2 is down-regulated by the overexpression of pCS2XWnt8, shown are stage 10.5 embryos with the blastopore down and the dorsal side to the top. H: Expression of the mesodermal marker Xbra appeared unaltered; shown are stage 11 embryos in vegetal view with dorsal up. I: Finally, expression of the posterior marker Xcad3 is shifted to a more anterior position as a result of the Xwnt8 gain-of-function; shown are embryos at stage 17, dorsal view with anterior up. |
