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XB-ART-42045
Development October 1, 2010; 137 (19): 3293-302.

Anterior neural development requires Del1, a matrix-associated protein that attenuates canonical Wnt signaling via the Ror2 pathway.

Takai A , Inomata H , Arakawa A , Yakura R , Matsuo-Takasaki M , Sasai Y .


Abstract
During early embryogenesis, the neural plate is specified along the anterior-posterior (AP) axis by the action of graded patterning signals. In particular, the attenuation of canonical Wnt signals plays a central role in the determination of the anterior brain region. Here, we show that the extracellular matrix (ECM) protein Del1, expressed in the anterior neural plate, is essential for forebrain development in the Xenopus embryo. Overexpression of Del1 expands the forebrain domain and promotes the formation of head structures, such as the eye, in a Chordin-induced secondary axis. Conversely, the inhibition of Del1 function by a morpholino oligonucleotide (MO) represses forebrain development. Del1 also augments the expression of forebrain markers in neuralized animal cap cells, whereas Del1-MO suppresses them. We previously reported that Del1 interferes with BMP signaling in the dorsal-ventral patterning of the gastrula marginal zone. By contrast, we demonstrate here that Del1 function in AP neural patterning is mediated mainly by the inhibition of canonical Wnt signaling. Wnt-induced posteriorization of the neural plate is counteracted by Del1, and the Del1-MO phenotype (posteriorization) is reversed by Dkk1. Topflash reporter assays show that Del1 suppresses luciferase activities induced by Wnt1 and beta-catenin. This inhibitory effect of Del1 on canonical Wnt signaling, but not on BMP signaling, requires the Ror2 pathway, which is implicated in non-canonical Wnt signaling. These findings indicate that the ECM protein Del1 promotes forebrain development by creating a local environment that attenuates the cellular response to posteriorizing Wnt signals via a unique pathway.

PubMed ID: 20823067
Article link: Development

Genes referenced: acta2 chdh chrd.1 ctnnb1 dkk1 edil3 egf egr2 en2 fgf2 foxg1 frzb gsc hoxd1 lyn myod1 ncam1 nlk not otx2 pax6 pc.1 rax ror2 sall2 six3 tbxt tcf7l1 wif1 wnt1 wnt11 wnt8a
Antibodies: Ctnnb1 Ab6
Morpholinos: edil3 MO1 ror2 MO2


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