Noggin acts downstream of Wnt and Sonic Hedgehog to antagonize BMP4 in avian somite patterning.
In the vertebrate embryo, the lateral compartment of the somite gives rise to muscles of the limb and body wall and is patterned in response to lateral-plate-derived BMP4. Activation of the myogenic program distinctive to the medial somite, i.e. relatively immediate development of the epaxial muscle lineage, requires neutralization of this lateral signal. We have analyzed the properties of molecules likely to play a role in opposing lateral somite specification by BMP4. We propose that the BMP4 antagonist Noggin plays an important role in promoting medial somite patterning in vivo. We demonstrate that Noggin expression in the somite is under the control of a neural-tube-derived factor, whose effect can be mimicked experimentally by Wnt1. Wnt1 is appropriately expressed in the neural tube. Furthermore, we show that Sonic Hedgehog is able to activate ectopic expression of Noggin resulting in the blocking of BMP4 specification of the lateral somite. Our results are consistent with a model in which Noggin activation lies downstream of the SHH and Wnt signaling pathways.
Hirsinger
E
E
Institut de Biologie du Développement de Marseille, LGPD-UMR CNRS 9943 Campus de Luminy - case 907, France.
Duprez
D
D
Jouve
C
C
Malapert
P
P
Cooke
J
J
Pourquié
O
O
D000818:Animals; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors*; D016466:CHO Cells; D002352:Carrier Proteins; D002642:Chick Embryo; D006224:Cricetinae; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins; D017403:In Situ Hybridization; D008954:Models, Biological; D009132:Muscles / Q000196:embryology / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D019170:Somites / Q000166:cytology / Q000378:metabolism*; D015534:Trans-Activators; D051153:Wnt Proteins; D051155:Wnt1 Protein; D014981:Xenopus; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D000099176:Noggin Protein
D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D053823:Hedgehog Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; D000099176:Noggin Protein; C495249:WNT1 protein, Xenopus; C525812:bmp4 protein, Xenopus; C525813:bmp4 protein, zebrafish