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.
XB-ART-45061
PLoS Biol January 1, 2012; 10 (3): e1001286.

Maternal xNorrin, a canonical Wnt signaling agonist and TGF-β antagonist, controls early neuroectoderm specification in Xenopus.

Xu S , Cheng F , Liang J , Wu W , Zhang J .


Abstract
Dorsal-ventral specification in the amphibian embryo is controlled by β-catenin, whose activation in all dorsal cells is dependent on maternal Wnt11. However, it remains unknown whether other maternally secreted factors contribute to β-catenin activation in the dorsal ectoderm. Here, we show that maternal Xenopus Norrin (xNorrin) promotes anterior neural tissue formation in ventralized embryos. Conversely, when xNorrin function is inhibited, early canonical Wnt signaling in the dorsal ectoderm and the early expression of the zygotic neural inducers Chordin, Noggin, and Xnr3 are severely suppressed, causing the loss of anterior structures. In addition, xNorrin potently inhibits BMP- and Nodal/Activin-related functions through direct binding to the ligands. Moreover, a subset of Norrin mutants identified in humans with Norrie disease retain Wnt activation but show defective inhibition of Nodal/Activin-related signaling in mesoderm induction, suggesting that this disinhibition causes Norrie disease. Thus, xNorrin is an unusual molecule that acts on two major signaling pathways, Wnt and TGF-β, in opposite ways and is essential for early neuroectoderm specification.

PubMed ID: 22448144
PMC ID: PMC3308935
Article link: PLoS Biol

Genes referenced: actl6a ag1 babam2 chrd.1 foxg1 gal.2 gsc hoxc9-like ndp nodal nodal1 nodal3.1 nodal3.2 nog sox3 tbxt wnt11
GO keywords: ectoderm development [+]
Antibodies: Myc Ab5 Notochord Ab2
Morpholinos: ndp MO1 ndp MO2

Disease Ontology terms: Norrie disease
OMIMs: NORRIE DISEASE; ND

Article Images: [+] show captions
References:
Agius, 2000, Pubmed, Xenbase [+]


Xenbase: The Xenopus laevis and X. tropicalis resource.
Version: 4.12.1


Major funding for Xenbase is provided by grant P41 HD064556