Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Matthews HK
,
Broders-Bondon F
,
Thiery JP
,
Mayor R
.
???displayArticle.abstract??? wnt11r is a recently identified member of the Wnt family of genes, which has been proposed to be the true Xenopus homologue to the mammalian wnt11 gene. In this study we have examined the role of wnt11r on neural crest development. Expression analysis of wnt11r and comparison with the neural crest marker snail2 and the noncanonical Wnt, wnt11, shows wnt11r is expressed at the medial or neural plate side of the neural crest while wnt11 is expressed at the lateral or epidermal side. Injection of wnt11r morpholino leads to strong inhibition of neural crest migration with no effect on neural crest induction or maintenance. This effect can be rescued by co-injection of Wnt11r but not by Wnt11 mRNA, demonstrating the specificity of the loss of function treatment. Finally, neural crest graft experiments show that wnt11r is required in a non-cell-autonomous manner to control neural crest migration.
Figure 1. Wnt11 and Wnt11r are expressed adjacent to the neural crest before migration. In situ hybridization was carried out to compare the expression patterns of wnt11r, wnt11, and snail2 in Xenopus embryo. A-D: Dorsal view of stage 17 embryos showing expression patterns of snail2 (A,D), wnt11r (B,C) and wnt11 (C,D). Anterior is to the top, arrow: Wnt11r expression adjacent to the NC; arrowhead: gap between wnr11r and wnt11 expression. C,D: Note how wnt11 and wnt11r flank the neural crest (marked with snail2) on both sides. E: Schematic representation of a transverse section through a stage 17 embryo with wnt11 (red) and wnt11r (blue) expressing cells on either side of the neural crest (green); arrow: direction of neural crest migration; np, neural plate; nc, neural crest; e, epidermis; n, notochord; m, mesoderm. F,G: Lateral view of later stage embryos showing the expression of wnt11r at stage 27 (F) and stage 35 (G), arrow: expression in migrating neural crest. H: Higher magnification of wnt11r expression in the trunk region; arrow indicates expression in the dorsal fin. I: Higher magnification image of wnt11r expression in the head of a stage 35 embryo, arrow denotes branchial arches.
Figure 2. Wnt11r is required for neural crest migration but not for induction. Xenopus embryos were injected with wnt11r MO and/or mRNA at the eight-cell stage and fixed at stage 14, 17, or 24 for visualization of the neural crest by snail2 in situ hybridization. A-C: Dorsal view of neurula embryos, anterior is to top; arrowhead: injected side. Expression of neural crest marker gene, snail2, is unaffected by injection of 30 ng of wnt11r MO at stage 14 (A) or stage 17 (B) or by overexpression of 1 ng of wnt11r mRNA (C). The site of injection is indicated by pale blue fluorescein staining. D,E: Lateral view of stage 24 embryos, anterior is to the left. Cranial neural crest migration proceeds as normal in the uninjected side of an embryo (D, arrow), but is disrupted by injection of 15 ng of wnt11r MO (E). F,G: Dorsal view (F) and transverse section (G) of a wnt11r MO embryo shows the accumulation of NC cells next to neural tube on injected side, asterisk indicates injected side. H-J: Rescue experiment: The effect of the wnt11r MO can be rescued by co-injection of 1 ng of wnt11r mRNA (H), but not by 1 ng of wnt11 mRNA (I). Sites of injection are indicated with light blue staining as before. J: Quantification of rescue experiment.
