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XB-ART-1130
Mech Dev. December 1, 2005; 122 (12): 1322-39.

Role of crescent in convergent extension movements by modulating Wnt signaling in early Xenopus embryogenesis.

Shibata M , Itoh M , Hikasa H , Taira S , Taira M .


Abstract
The Xenopus gene crescent encodes a member of the secreted Frizzled-related protein (sFRP) family and is expressed in the head organizer region. However, the target and function of Crescent in early development are not well understood. Here, we describe a role of Crescent in the regulation of convergent extension movements (CEMs) during gastrulation and neurulation. We show that overexpression of Crescent in whole embryos or animal caps inhibits CEMs without affecting tissue specification. Consistent with this, Crescent efficiently forms complexes with Xwnt11 and Xwnt5a, in contrast to another sFRP, Frzb1. As expected, the inhibitory effect of Crescent or Xwnt11 on CEMs is cancelled when both proteins are coexpressed in the neuroectoderm. Interestingly, when coexpressed in the dorsal mesoderm, the activity of Xwnt11 is rather enhanced by Crescent. Supporting this finding, the inhibition of CEMs by Crescent in mesodermalized but not neuralized animal caps is reversed by the dominant-negative form of Cdc42, a putative mediator of Wnt/Ca2+ pathway. Antisense morpholino oligos for Crescent impair neural plate closure and elicit microcephalic embryos with a shortened trunk without affecting early tissue specification. These data suggest a potential role for Crescent in head formation by regulating a non-canonical Wnt pathway positively in the adjacent posterior mesoderm and negatively in the overlying anterior neuroectoderm.

PubMed ID: 16274967
Article link: Mech Dev.

Genes referenced: cdc42 chrd.1 dkk1 dlx3 dvl2 foxd1 frzb frzb2 fzd7 gal.2 gsc hes4 myc myod1 nrp1 otx2 rax ror2 sesn1 sox2 tbxt wnt11b wnt3a wnt4 wnt5a wnt8a

Morpholinos referenced: frzb2 MO1

Article Images: [+] show captions


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