The Wnt-activated Xiro1 gene encodes a repressor that is essential for neural development and downregulates Bmp4.
In the early Xenopus embryo, the Xiro homeodomain proteins of the Iroquois (Iro) family control the expression of proneural genes and the size of the neural plate. We report that Xiro1 functions as a repressor that is strictly required for neural differentiation, even when the BMP4 pathway is impaired. We also show that Xiro1 and Bmp4 repress each other. Consistently, Xiro1 and Bmp4 have complementary patterns of expression during gastrulation. The expression of Xiro1 requires Wnt signaling. Thus, Xiro1 is probably a mediator of the known downregulation of Bmp4 by Wnt signaling.
Gómez-Skarmeta
J
J
Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Cantoblanco, Spain. jlgomez@cbm.uam.es
de La Calle-Mustienes
E
E
Modolell
J
J
D000818:Animals; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D019070:Cell Lineage; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D004475:Ectoderm / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000378:metabolism; D005775:Gastrula / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D024002:HMGB Proteins; D006651:Histocytochemistry; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D017403:In Situ Hybridization; D008648:Mesoderm / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics; D009420:Nervous System / Q000196:embryology* / Q000378:metabolism; D039942:Neuropilin-1; D009687:Nuclear Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D055748:SOXB1 Transcription Factors; D015398:Signal Transduction; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051153:Wnt Proteins; D014981:Xenopus / Q000196:embryology* / Q000235:genetics; D029867:Xenopus Proteins; D029961:Zebrafish Proteins
D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D004268:DNA-Binding Proteins; D024002:HMGB Proteins; D018398:Homeodomain Proteins; C110460:IRX2 protein, Xenopus; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D055748:SOXB1 Transcription Factors; D014157:Transcription Factors; D051153:Wnt Proteins; D029867:Xenopus Proteins; C484675:Xiro1 protein, Xenopus; D029961:Zebrafish Proteins; C525812:bmp4 protein, Xenopus; C525813:bmp4 protein, zebrafish; C527781:sox2 protein, Xenopus; D039942:Neuropilin-1; D004247:DNA