β-catenin-driven endomesoderm specification is a Bilateria-specific novelty

• DOI: 10.1038/s41467-025-57109-w
• Publication Date: 2025-03-12T21:37:46Z
• Authors: Tatiana Lebedeva; Johan Boström; Stanislav Kremnyov; David Mörsdorf; Isabell Niedermoser; Evgeny Genikhovich; Andreas Hejnol; Igor Adameyko; Grigory Genikhovich
• Keywords: Bilateria

Abstract Endomesoderm specification by a maternal β-catenin signal and body axis patterning interpreting gradient of zygotic Wnt/β-catenin signalling was suggested to predate the split between Bilateria their sister clade Cnidaria. However, in Cnidaria, roles these processes have not been demonstrated directly. Here, tagging endogenous cnidarian Nematostella vectensis , we confirm that its oral-aboral is indeed patterned signalling. Strikingly, show that, contrast bilaterians, endomesoderm repressed takes place nuclear β-catenin-negative part embryo. This completely changes accepted paradigm suggests β-catenin-dependent bilaterian innovation linking subsequent posterior-anterior patterning.