ИСТИНА

Lycopodina hypogea is a demosponge that belongs to the deep sea family Cladorhizidae, which gave up the classical filtering strategy to become exclusively carnivorous, although without any digestive cavity. A unique body plan with well-defined body parts, an exciting ecology, adaptive strategy and reproduction, together with ability to survive in laboratory, make L. hypogea a promising model. Six research projects are currently developed in five laboratories to create a research synergy around this fascinating species: -Tissue organisation, cell distribution and cell ultrastructure in the different parts of the sponge body (filaments, stalk and foot). -Epigenetic regulation: involvement of the Polycomb and Trithorax groups in tissue homeostasis during the digestive cycle using transcriptomics and cell biology. -Stolonial budding: cellular and molecular basis of asexual reproduction by the formation of stolons and migrating buds. -Supracellular migration: coordination of cell migration during stolonial budding by supracellular structures providing mechanical integrity and facilitating movements. -Actomyosin contraction: regulation of actomyosin contraction in morphogenesis and regeneration through cytoskeletal rearrangements and signaling pathways. -Signal transduction: changes in cell mechanics and shape through actin, myosin, and Rho GTPhases activation, with the focus on the key actors in signal transduction, tyrosin phosphoryled proteins at the focal adhesions-like level. By comparing the body structure, development and life cycle of carnivorous sponges with those of other sponges, we gain insights into the mechanisms and patterns of biodiversity evolution. The establishment of L. hypogea as a new model makes a significant contribution to Evo-Devo, cell biology and evolutionary ecology.