BMP4 plays a key role in left-right patterning in chick embryos by maintaining Sonic Hedgehog asymmetry.
In chick embryos, the first signs of left-right asymmetry are detected in Hensen's node, essentially by left-sided Sonic Hedgehog (Shh) expression. After a gap of several hours, SHH induces polarized gene activities in the left paraxial mesoderm. We show that during this time period, BMP4 signaling is necessary and sufficient to maintain Shh asymmetry within the node. SHH and BMP4 proteins negatively regulate each other's transcription, resulting in a strict complementarity between these two gene patterns on each side of the node. Noggin, present in the midline at this stage, limits BMP4 spreading. Moreover, BMP4 is downstream to Activin signals and controls Fgf8. Thus, early BMP4 signaling coordinates left and right pathways in Hensen's node.
Monsoro-Burq
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A
Institut d'Embryologie Cellulaire et Moléculaire, FRE 2160, 49 bis avenue de la Belle Gabrielle, 94736 Nogent-sur-Marne Cedex, France.
Le Douarin
N M
NM
D028341:Activins; D000818:Animals; D019521:Body Patterning / Q000235:genetics*; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000235:genetics* / Q000378:metabolism*; D002352:Carrier Proteins; D002642:Chick Embryo; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins; D017403:In Situ Hybridization; D007265:Inhibins / Q000235:genetics / Q000378:metabolism; D008648:Mesoderm / Q000502:physiology; D020897:Organizers, Embryonic / Q000196:embryology* / Q000502:physiology*; D011506:Proteins / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D015534:Trans-Activators; D000099176:Noggin Protein
D028341:Activins; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors; D053823:Hedgehog Proteins; D007265:Inhibins; D011506:Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D000099176:Noggin Protein