Secreted noggin protein mimics the Spemann organizer in dorsalizing Xenopus mesoderm.
A dorsalizing signal acts during gastrulation to change the specification of lateral mesodermal tissues from ventral (blood, mesenchyme) to more dorsal fates (muscle, heart, pronephros). This signal, from Spemann's organizer, cannot be mimicked by the mesoderm inducers activin and fibroblast growth factor. The gene noggin is expressed in the organizer, and could be the dorsalizing signal. Here we show that soluble noggin protein added to ventral marginal zones during gastrulation induces muscle, but that activin does not. Dorsal pattern can be partially rescued in ventralized embryos by injection of a plasmid that expresses noggin during gastrulation. The results suggest that the noggin product may be the dorsalizing signal from the organizer.
Smith
W C
WC
Department of Molecular and Cell Biology, University of California, Berkeley 94720.
Knecht
A K
AK
Wu
M
M
Harland
R M
RM
D028341:Activins; D000818:Animals; D015152:Blotting, Northern; D002352:Carrier Proteins; D002454:Cell Differentiation; D004627:Embryonic Induction; D005775:Gastrula; D006133:Growth Substances / Q000494:pharmacology; D007265:Inhibins / Q000494:pharmacology; D009132:Muscles / Q000196:embryology; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D014981:Xenopus / Q000196:embryology*; D000099176:Noggin Protein
D028341:Activins; D002352:Carrier Proteins; D006133:Growth Substances; D007265:Inhibins; D011506:Proteins; D000099176:Noggin Protein