In Xenopus embryos, BMP heterodimers are not required for mesoderm induction, but BMP activity is necessary for dorsal/ventral patterning.
The activity of bone morphogenetic protein (BMP) heterodimers has been shown to be more potent than that of homodimers in a number of contexts, including mesoderm induction. Although BMP-2/7 and -4/7 heterodimers are potent inducers of ventral mesoderm in ectodermal explants, we show that they are not a necessary component of the primary mesoderm-inducing signal in intact Xenopus embryos. The secreted BMP antagonists noggin and gremlin both efficiently block mesoderm induction by BMP homo- and heterodimers in animal caps. When these antagonists are ectopically expressed in the ventral marginal zone of early embryos the initial formation of mesoderm as indicated by panmesodermal markers remains unaffected. Only the subsequent dorsal/ventral patterning of this mesoderm appears to be altered, with expression of a number of organizer-specific transcripts observed in the marginal zone where BMP signaling has been abolished. Thus, we conclude that BMPs do not contribute an essential signal to mesodermal induction or patterning until gastrulation. The activities of noggin and gremlin are strikingly different from that of the multifunctional antagonist cerberus, which completely abolishes mesoderm induction when misexpressed during early development.
Eimon
P M
PM
Department of Molecular Biology, University of California, Berkeley, California, 94720-3202, USA.
Harland
R M
RM
D000818:Animals; D015415:Biomarkers / Q000032:analysis; D019521:Body Patterning / Q000187:drug effects*; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D002352:Carrier Proteins; D016207:Cytokines; D019281:Dimerization; D018507:Gene Expression Regulation, Developmental; D051956:Goosecoid Protein; D018398:Homeodomain Proteins / Q000378:metabolism; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins; D008648:Mesoderm / Q000378:metabolism*; D008845:Microinjections; D011485:Protein Binding; D011506:Proteins / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D012097:Repressor Proteins; D015398:Signal Transduction; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D014981:Xenopus / Q000196:embryology*; D029867:Xenopus Proteins; D000099176:Noggin Protein
D015415:Biomarkers; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D016207:Cytokines; D051956:Goosecoid Protein; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D029867:Xenopus Proteins; D000099176:Noggin Protein; C486400:GREM1 protein, Xenopus; C525812:bmp4 protein, Xenopus; C525822:bmp7.1 protein, Xenopus; C100866:cer1 protein, Xenopus