Lrp6 is required for convergent extension during Xenopus gastrulation.

Tahinci E, Thorne CA, Franklin JL, Salic A, Christian KM, Lee LA, Coffey RJ, Lee E
Development. 2007 134 (22): 4095-106

PMID: 17965054 · PMCID: PMC4428168 · DOI:10.1242/dev.010272

Wnt signaling regulates beta-catenin-mediated gene transcription and planar cell polarity (PCP). The Wnt co-receptor, Lrp6, is required for signaling along the beta-catenin arm. We show that Lrp6 downregulation (by morpholino injection) or overexpression in Xenopus embryos disrupts convergent extension, a hallmark feature of Wnt/PCP components. In embryos with decreased Lrp6 levels, cells of the dorsal marginal zone (DMZ), which undergoes extensive cellular rearrangements during gastrulation, exhibit decreased length:width ratios, decreased migration, and increased numbers of transient cytoplasmic protrusions. We show that Lrp6 opposes Wnt11 activity and localizes to the posterior edge of migrating DMZ cells and that Lrp6 downregulation enhances cortical and nuclear localization of Dsh and phospho-JNK, respectively. Taken together, these data suggest that Lrp6 inhibits Wnt/PCP signaling. Finally, we identify the region of the Lrp6 protein with Wnt/PCP activity to a stretch of 36 amino acids, distinct from regions required for Wnt/beta-catenin signaling. We propose a model in which Lrp6 plays a critical role in the switch from Wnt/PCP to Wnt/beta-catenin signaling.

MeSH Terms (21)

Amino Acid Sequence Animals Animals, Genetically Modified beta Catenin Body Patterning Cell Polarity Cells, Cultured Embryo, Nonmammalian Gastrulation Gene Expression Regulation, Developmental Humans Low Density Lipoprotein Receptor-Related Protein-6 Mesoderm Models, Biological Molecular Sequence Data Receptors, LDL Sequence Homology, Amino Acid Signal Transduction Tissue Distribution Wnt Proteins Xenopus

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