Nodal signaling and vertebrate germ layer formation.
The understanding of germ layer formation in vertebrates began with classical experimental embryology. Early in the 20th century, Spemann and Mangold (1924) identified a region of the early embryo capable of inducing an entire embryonic axis. Termed the dorsal organizer, the tissue and the activity have been shown to exist in all vertebrates examined. In mice, for example, the activity resides in a region of the gastrula embryo known as the node. Experiments by the Dutch embryologist Nieuwkoop (1967a, 1967b, 1973, 1977) showed that a signal derived from the vegetal half of the amphibian embryo is responsible for the formation of mesoderm. Nieuwkoop's results allowed the development of in vitro assays that led, in the late 1980s and early 1990s, to the identification of growth factors essential for germ layer formation. Through more recent genetic investigations in mice and zebrafish, we now know that one class of secreted growth factor, called Nodal because of its localized expression in the mouse node, is essential for formation of mesoderm and endoderm and for the morphological rearrangements that occur during gastrulation.
Weng
Wei
W
Vertebrate Development and Genetics (Team31), Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge, United Kingdom.
Stemple
Derek L
DL
D028341:Activins / Q000096:biosynthesis; D000818:Animals; D019521:Body Patterning; D004627:Embryonic Induction; D005775:Gastrula / Q000502:physiology; D005855:Germ Layers / Q000502:physiology*; D028322:Inhibin-beta Subunits / Q000096:biosynthesis; D047908:Intracellular Signaling Peptides and Proteins; D008648:Mesoderm / Q000502:physiology; D051379:Mice; D055457:Nodal Protein; D055456:Nodal Signaling Ligands; D020897:Organizers, Embryonic; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000096:biosynthesis*; D014714:Vertebrates; D029867:Xenopus Proteins; D014982:Xenopus laevis; D029961:Zebrafish Proteins
D047908:Intracellular Signaling Peptides and Proteins; D055457:Nodal Protein; D055456:Nodal Signaling Ligands; C526008:Nodal protein, mouse; D016212:Transforming Growth Factor beta; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; C422405:activin A; C485171:ndr1 protein, zebrafish; C512832:ndr2 protein, zebrafish; C512833:nodal1 protein, Xenopus; D028341:Activins; D028322:Inhibin-beta Subunits