title: Twisted gastrulation is required for forebrain specification and cooperates with Chordin to inhibit BMP signaling during X. tropicalis gastrulation.
abstract: In the developing vertebrate embryo, proper dorsal-ventral patterning relies on BMP antagonists secreted by the organizer during gastrulation. The BMP antagonist chordin has a complex interaction with BMPs that is governed in part by its interaction with the secreted protein twisted gastrulation (tsg). In different contexts, tsg has activity as either a BMP agonist or as a BMP antagonist. Using morpholino oligonucleotides in Xenopus tropicalis, we show that reducing tsg gene product results in a ventralized embryo, and that tsg morphants specifically lack a forebrain. We provide new evidence that tsg acts as a BMP antagonist during X. tropicalis gastrulation since the tsg depletion phenotype can be rescued in two ways: by chordin overexpression and by BMP depletion. We conclude that tsg acts as a BMP antagonist in the context of the frog gastrula, and that it acts cooperatively with chordin to establish dorsal structures and particularly forebrain tissue during development.
authors.affiliation: Department of Molecular and Cell Biology, University of California - Berkeley, 94720-3204, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Wills
authors.forename: Richard M
authors.initials: RM
authors.lastname: Harland
authors.forename: Mustafa K
authors.initials: MK
authors.lastname: Khokha
mesh_terms: D000818:Animals; D001483:Base Sequence; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D015536:Down-Regulation; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D005775:Gastrula / Q000378:metabolism; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000037:antagonists & inhibitors*; D008969:Molecular Sequence Data; D016548:Prosencephalon / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000494:pharmacology; D015398:Signal Transduction; D014981:Xenopus / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D029867:Xenopus Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*
chemical_list: D019485:Bone Morphogenetic Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; C477670:TWSG1 protein, Xenopus; D029867:Xenopus Proteins; C121859:bambi-A protein, Xenopus; C054234:chordin