Isolation and characterization of Wnt pathway‐related genes from Porifera

Abstract

The Wnt signal acts by binding to Frizzled receptors, with the subsequent activation of two different signal transduction cascades, the canonical and the non-canonical Wnt pathways, involved in cell growth, differentiation, migration and fate. The canonical pathway functions through the translocation of beta-catenin to the nucleus and the activation of TCF/LEF transcription factors; it plays an important role in developmental patterning and cell fate decisions during embryogenesis. The non-canonical Wnt pathway is responsible for the planar cell polarity process in invertebrates, and for the convergent-extension movements during vertebrate gastrulation. The final effect of the non-canonical Wnt pathway is the rearrangement of the cell cytoskeleton, through the activation of the subfamily of Ras-like small GTPases. In a recent report we described for the first time the isolation of a Wnt-related gene, Sd-Frizzled, from the most basal animal phylum, the Porifera. In the present study we report the isolation and phylogenetic characterization of several Wnt pathway-related genes from the sponge Suberites domuncula: Sd-TCF/LEF, Sd-GSK3, a recently discovered molecule with a putative function as a Wnt regulator (Sd-LZIC), the small Rho GTPases Sd-RhoA, Sd-Cdc42, and their effector Sd-mrlc. Also the isolation of a secreted frizzled related protein sFRP from another sponge species (Lubomirskia baicalensis) is reported.