WNT-β-Catenin Signalling and Epithelial Patterning in the Homoscleromorph Sponge OscarellaReportar como inadecuado




WNT-β-Catenin Signalling and Epithelial Patterning in the Homoscleromorph Sponge Oscarella - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Sponges branch basally in the metazoan phylogenetic tree and are thus well positioned to provide insights into the evolution of mechanisms controlling animal development, likely to remain active in adult sponges. Of the four sponge clades, the Homoscleromorpha are of particular interest as they alone show the -true- epithelial organization seen in other metazoan phyla the Eumetazoa. We have examined the deployment in sponges of Wnt signalling pathway components, since this pathway is an important regulator of many developmental patterning processes. We identified a reduced repertoire of three divergent Wnt ligand genes in the recently-sequenced Amphimedon queenslandica demosponge genome and two Wnts from our EST collection from the homoscleromorph Oscarella lobularis, along with well-conserved genes for intracellular pathway components β-catenin, GSK3β. Remarkably, the two O. lobularis Wnt genes showed complementary expression patterns in relation to the evenly spaced ostia canal openings of the exopinacoderm ectoderm, highly reminiscent of Wnt expression during skin appendage formation in vertebrates. Furthermore, experimental activation of the Wnt-β-catenin pathway using GSK3β inhibitors provoked formation of ectopic ostia, as has been shown for epithelial appendages in Eumetazoa. We thus suggest that deployment of Wnt signalling is a common and perhaps ancient feature of metazoan epithelial patterning and morphogenesis.



Autor: Pascal Lapébie , Eve Gazave, Alexander Ereskovsky, Romain Derelle, Chantal Bézac, Emmanuelle Renard, Evelyn Houliston, Carole B

Fuente: http://plos.srce.hr/



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