Evidence for Involvement of Wnt Signalling in Body Polarities, Cell Proliferation, and the Neuro-Sensory System in an Adult Ctenophore

摘要: Signalling through the Wnt family of secreted proteins originated in a common metazoan ancestor and greatly influenced evolution animal body plans. In bilaterians, signalling plays multiple fundamental roles during embryonic development adult tissues, notably axial patterning, neural stem cell regulation. Studies various cnidarian species have particularly highlighted evolutionarily conserved role Wnt/β-catenin pathway specification patterning primary axis. However another key non-bilaterian phylum, Ctenophora, Wnts are not involved early establishment axis embryogenesis. We analysed expression ctenophore Pleurobrachia pileus 11 orthologues genes including all ligands Fz receptors several members intracellular β-catenin machinery. All strongly expressed around mouth margin at oral pole, evoking centre cnidarians. This observation is consistent with polarisation by being universal feature, secondarily lost ctenophores but retained adult. addition, local was seen anatomical structures locomotory comb rows, where their complex deployment suggests control polarity. Other important contexts involvement which probably evolved before ctenophore/cnidarian/bilaterian split include proliferating cells progenitors irrespective types, developing as well differentiated neuro-sensory structures.