title: A deuterostome origin of the Spemann organiser suggested by Nodal and ADMPs functions in Echinoderms.
abstract: During development of chordates, establishment of the body plan relies on the activity of an organizing centre located on the dorsal side of the embryo that patterns the embryo and induces neural tissue. Intriguingly, the evolutionary origin of this crucial signalling centre remains unclear and whether analogous organizers regulate D/V patterning in other deuterostome or protostome phyla is not known. Here we provide evidence that the ventral ectoderm of the sea urchin embryo is a long-range organizing centre that shares several fundamental properties with the Spemann organizer: the ability to induce duplicated embryonic axes when ectopically induced, the ability to induce neural fate in neighbouring tissues and the ability to finely regulate the level of BMP signalling by using an autoregulatory expansion-repression mechanism. These findings suggest that the evolutionary origin of the Spemann organizer is more ancient than previously thought and that it may possibly be traced back to the common ancestor of deuterostomes.
authors.affiliation: Institut de Biologie Valrose, iBV, UMR 7277 CNRS, Inserm U1091, UNS, University of Nice Sophia Antipolis Nice 06108, 2 France.
authors.forename: François
authors.initials: F
authors.lastname: Lapraz
authors.affiliation: Institut de Biologie Valrose, iBV, UMR 7277 CNRS, Inserm U1091, UNS, University of Nice Sophia Antipolis Nice 06108, 2 France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Haillot
authors.affiliation: Institut de Biologie Valrose, iBV, UMR 7277 CNRS, Inserm U1091, UNS, University of Nice Sophia Antipolis Nice 06108, 2 France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Lepage
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D020440:Gene Duplication; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D007814:Larva / Q000502:physiology; D008024:Ligands; D008969:Molecular Sequence Data; D055457:Nodal Protein / Q000235:genetics / Q000378:metabolism*; D047328:Paracentrotus / Q000378:metabolism*; D010802:Phylogeny; D015398:Signal Transduction
chemical_list: D019485:Bone Morphogenetic Proteins; D008024:Ligands; D055457:Nodal Protein