title: Frizzled-8 is expressed in the Spemann organizer and plays a role in early morphogenesis.
abstract: Wnts are secreted signaling molecules implicated in a large number of developmental processes. Frizzled proteins have been identified as likely receptors for Wnt ligands in vertebrates and invertebrates, but a functional role for vertebrate frizzleds has not yet been defined. To assess the endogenous role of frizzled proteins during vertebrate development, we have identified and characterized a Xenopus frizzled gene (xfz8). It is highly expressed in the deep cells of the Spemann organizer prior to dorsal lip formation and in the early involuting marginal zone. Ectopic expression of xfz8 in ventral cells leads to complete secondary axis formation and can synergize with Xwnt-8 while an inhibitory form of xfz8 (Nxfz8) blocks axis duplication by Xwnt-8, consistent with a role for xfz8 in Wnt signal transduction. Expression of Nxfz8 in dorsal cells has profound effects on morphogenesis during gastrulation and neurulation that result in dramatic shortening of the anterior-posterior axis. Our results suggest a role for xfz8 in morphogenesis during the gastrula stage of embryogenesis.
authors.affiliation: Cell and Molecular Biology and Biochemistry Graduate Groups, Howard Hughes Medical Institute and Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Deardorff
authors.forename: C
authors.initials: C
authors.lastname: Tan
authors.forename: L J
authors.initials: LJ
authors.lastname: Conrad
authors.forename: P S
authors.initials: PS
authors.lastname: Klein
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004627:Embryonic Induction / Q000502:physiology; D051157:Frizzled Receptors; D005775:Gastrula / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins; D008845:Microinjections; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000502:physiology*; D011506:Proteins / Q000737:chemistry* / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000737:chemistry*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000502:physiology; D051153:Wnt Proteins; D014981:Xenopus / Q000254:growth & development*; D029867:Xenopus Proteins; D029961:Zebrafish Proteins
chemical_list: C113865:FZD8 protein, Xenopus; D051157:Frizzled Receptors; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D051153:Wnt Proteins; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; C100866:cer1 protein, Xenopus; C495248:wnt8a protein, Xenopus