Despite the essential role of the spindle assembly checkpoint in somatic cells, work in frog, worm and fish embryos has shown that microtubule perturbations that lead to erroneous kinetochore-spindle associations do not block mitosis during early embryogenesis, suggesting that the SAC is relaxed in early metazoan embryos. A main interest of our group is to understand how the spindle checkpoint is maintained silent in embryos and to molecularly dissect mitotic control during development, to determine how the mitotic machinery has adapted to the embryonic cell cycle and how aneuploidy is prevented during embryonic development.

   The data currently available on spindle checkpoint response during development are difficult to compare, as they refer to different embryonic stages and different microtubule perturbations. To evaluate the variability in spindle checkpoint activity during different embryonic stages, we are currently performing a multispecies comparison of the mitotic response to microtubule depolymerization in embryos representative of the major metazoan groups : cnidarian (Clytia hemisphaerica and Nematostella vectensis), mollusks (Mytilus galloprovincialis), echinoderms (Paracentrotus lividus, Sphaerechinus granularis, Arbacia lixula and Strongilocentrotus purpuratus), cephalochordates (Branchiostoma lanceolatum) and tunicates (Phallusia mammillata and Ciona intestinalis).