title: Lef-1 and Tcf-3 transcription factors mediate tissue-specific Wnt signaling during Xenopus development.
abstract: Wnt signaling functions repeatedly during embryonic development to induce different but specific responses. What molecular mechanisms ensure that Wnt signaling triggers the correct tissue-specific response in different tissues? Early Xenopus development is an ideal model for addressing this fundamental question, since there is a dramatic change in the response to Wnt signaling at the onset of zygotic gene transcription: Wnt signaling components encoded by maternal mRNA establish the dorsal embryonic axis; zygotically expressed Xwnt-8 causes almost the opposite, by promoting ventral and lateral and restricting dorsal mesodermal development. Although Wnt signaling can function through different signal transduction cascades, the same beta-catenin-dependent, canonical Wnt signal transduction pathway mediates Wnt signaling at both stages of Xenopus development. Here we show that, while the function of the transcription factor XTcf-3 is required for early Wnt signaling to establish the dorsal embryonic axis, closely related XLef-1 is required for Wnt signaling to pattern the mesoderm after the onset of zygotic transcription. Our results show for the first time that different transcription factors of the Lef/Tcf family function in different tissues to bring about tissue-specific responses downstream of canonical Wnt signaling.
authors.affiliation: Netherlands Institute for Developmental Biology (NIOB), Hubrecht Laboratorium, Uppsalalaan 8, 3584CT, Utrecht, The Netherlands.
authors.forename: Giulietta
authors.initials: G
authors.lastname: Roël
authors.forename: Fiona S
authors.initials: FS
authors.lastname: Hamilton
authors.forename: Yoony
authors.initials: Y
authors.lastname: Gent
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Bain
authors.forename: Olivier
authors.initials: O
authors.lastname: Destrée
authors.forename: Stefan
authors.initials: S
authors.lastname: Hoppler
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics*; D004625:Embryo, Nonmammalian / Q000502:physiology; D005260:Female; D018507:Gene Expression Regulation, Developmental; D018392:Genomic Imprinting; D024002:HMGB Proteins / Q000378:metabolism*; D051821:Lymphoid Enhancer-Binding Factor 1; D009024:Morphogenesis / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D051820:TCF Transcription Factors; D058127:Transcription Factor 3; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic; D051153:Wnt Proteins; D029867:Xenopus Proteins; D014982:Xenopus laevis; D029961:Zebrafish Proteins; D015053:Zygote / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; D024002:HMGB Proteins; D051821:Lymphoid Enhancer-Binding Factor 1; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D051820:TCF Transcription Factors; C544917:Tcf3 protein, Xenopus; D058127:Transcription Factor 3; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors; D051153:Wnt Proteins; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; C495248:wnt8a protein, Xenopus; D011505:Protein-Tyrosine Kinases