Dkk1 and noggin cooperate in mammalian head induction.
Growth factor antagonists play important roles in mediating the inductive effects of the Spemann organizer in amphibian embryos and its equivalents in other vertebrates. Dual inhibition of Wnt and BMP signals has been proposed to confer head organizer activity. We tested the requirement of this coinhibition in Xenopus and mice. In Xenopus, simultaneous reduction of the BMP antagonists chordin and noggin, and the Wnt antagonist dickkopf1 (dkk1) leads to anterior truncations. In mice, compound mutants for dkk1 and noggin display severe head defects, with deletion of all head structures anterior to the mid-hindbrain boundary. These defects arise as a result of a failure in anterior specification at the gastrula stage. The results provide genetic evidence for the dual inhibition model and indicate that dkk1 and noggin functionally cooperate in the head organizer.
del Barco Barrantes
Ivan
I
Division of Molecular Embryology, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.
Davidson
Gary
G
Gröne
Hermann-Josef
HJ
Westphal
Heiner
H
Niehrs
Christof
C
D000818:Animals; D002352:Carrier Proteins; D004627:Embryonic Induction / Q000235:genetics; D006257:Head / Q000196:embryology; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D014981:Xenopus; D029867:Xenopus Proteins; D000099176:Noggin Protein
D002352:Carrier Proteins; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D029867:Xenopus Proteins; D000099176:Noggin Protein; C501127:Dkk1 protein, mouse; C110182:dkk1 protein, Xenopus