Dickkopf1 and the Spemann-Mangold head organizer.
Work in amphibians indicates that inhibition of Wnt and BMP signals is essential for head development and that head induction by the Spemann-Mangold organizer may be mediated by secreted Wnt antagonists. Wnts are potent posteriorizing factors and antagonize the Spemann-Mangold organizer. Dickkopf1 (dkk1) encodes a secreted effector expressed in head organizing centers of Xenopus, mouse and zebrafish. It acts as a Wnt inhibitor and is able together with BMP inhibitors to induce the formation of ectopic embryonic heads in Xenopus. It anteriorizes both mesendoderm and neuroectoderm, promoting prechordal plate and forebrain fates. Injection of inhibitory antibodies leads to microcephaly and cyclopia. Dkk1 thus is an essential mediator of the vertebrate head organizer.
Niehrs
C
C
Division of Molecular Embryology, Deutsches Krebsforschungszentrum, Heidelberg, Germany.
Kazanskaya
O
O
Wu
W
W
Glinka
A
A
D000818:Animals; D019521:Body Patterning; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors; D004627:Embryonic Induction; D006257:Head / Q000196:embryology; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D020897:Organizers, Embryonic / Q000502:physiology*; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors; D051153:Wnt Proteins; D014981:Xenopus / Q000196:embryology / Q000235:genetics; D029867:Xenopus Proteins; D015027:Zebrafish / Q000196:embryology / Q000235:genetics; D029961:Zebrafish Proteins
D019485:Bone Morphogenetic Proteins; C501127:Dkk1 protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D051153:Wnt Proteins; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; C110182:dkk1 protein, Xenopus; C501128:dkk1b protein, zebrafish; C094522:wnt8b protein, zebrafish