Publication Date:
2023-02-16
Description:
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Houston, D. W., Elliott, K. L., Coppenrath, K., Wlizla, M., & Horb, M. E. Maternal Wnt11b regulates cortical rotation during Xenopus axis formation: analysis of maternal-effect wnt11b mutants. Development, 149(17), (2022): dev.200552, https://doi.org/10.1242/dev.200552.
Description:
Asymmetric signalling centres in the early embryo are essential for axis formation in vertebrates. These regions (e.g. amphibian dorsal morula, mammalian anterior visceral endoderm) require stabilised nuclear β-catenin, but the role of localised Wnt ligand signalling activity in their establishment remains unclear. In Xenopus, dorsal β-catenin is initiated by vegetal microtubule-mediated symmetry breaking in the fertilised egg, known as ‘cortical rotation’. Localised wnt11b mRNA and ligand-independent activators of β-catenin have been implicated in dorsal β-catenin activation, but the extent to which each contributes to axis formation in this paradigm remains unclear. Here, we describe a CRISPR-mediated maternal-effect mutation in Xenopus laevis wnt11b.L. We find that wnt11b is maternally required for robust dorsal axis formation and for timely gastrulation, and zygotically for left-right asymmetry. Importantly, we show that vegetal microtubule assembly and cortical rotation are reduced in wnt11b mutant eggs. In addition, we show that activated Wnt coreceptor Lrp6 and Dishevelled lack behaviour consistent with roles in early β-catenin stabilisation, and that neither is regulated by Wnt11b. This work thus implicates Wnt11b in the distribution of putative dorsal determinants rather than in comprising the determinants themselves.
Description:
This work was funded by the University of Iowa (D.W.H.) and by grants from the National Institutes of Health (R01GM083999 to D.W.H.; R24OD030008 and P40OD010997 to M.E.H.). Open Access funding provided by The University of Iowa. Deposited in PMC for immediate release.
Keywords:
Xenopus
;
Dorsal axis
;
Wnt11
;
Wnt11b
;
Microtubules
;
Cortical rotation
;
CRISPR/Cas9
Repository Name:
Woods Hole Open Access Server
Type:
Article
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