Xwnt-8b: a maternally expressed Xenopus Wnt gene with a potential role in establishing the dorsoventral axis
| Autor: | Jan L. Christian, Randall T. Moon, Jeffrey D. Brown, Yanzhen Cui |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Mesoderm
animal structures Xenopus Molecular Sequence Data Polymerase Chain Reaction Prosencephalon Proto-Oncogene Proteins Ectoderm Genes Regulator Morphogenesis medicine Ultraviolet light Animals Amino Acid Sequence Molecular Biology In Situ Hybridization DNA Primers Base Sequence biology Alternative splicing Wnt signaling pathway Embryo Sequence Analysis DNA Zebrafish Proteins biology.organism_classification Molecular biology Wnt Proteins Alternative Splicing Phenotype medicine.anatomical_structure Neurula embryonic structures Forebrain Sequence Alignment Developmental Biology |
| Zdroj: | Development. 121:2177-2186 |
| ISSN: | 1477-9129 0950-1991 |
| DOI: | 10.1242/dev.121.7.2177 |
| Popis: | In amphibian embryos, establishment of dorsal-ventral asymmetry is believed to involve dorsal-ventral differences in vegetally derived mesoderm-inducing signals and/or differences in the competence of animal hemisphere (ectodermal) cells to respond to these signals. Previous studies have shown that certain Wnt proteins can generate an ectopic dorsal axis when misexpressed, and that they do so by modifying the response of ectodermal cells to inducers. None of these Wnt proteins are expressed at an appropriate time to do so in vivo. In this study, we describe the isolation and characterization of a full length cDNA for the Xenopus Wnt gene, Xwnt-8b, whose biological activity and expression pattern suggest that it may be involved in establishment of the dorsoventral axis. Both maternal and zygotic Xwnt-8b transcripts undergo alternative splicing to generate mRNAs which encode two different forms of Xwnt-8b protein. During early cleavage stages Xwnt-8b transcripts are confined primarily to animal hemisphere blastomeres, while zygotically derived Xwnt-8b transcripts are restricted almost exclusively to a band of cells in the prospective forebrain of neurula and tailbud stage embryos. Ectopically expressed Xwnt-8b can completely rescue dorsal development of embryos ventralized by exposure to ultraviolet light, and can induce a complete secondary axis in wild-type embryos. Axis induction is observed only if Xwnt-8b is supplied prior to the onset of zygotic gene transcription. This biological activity, together with the presence of maternal Xwnt-8b transcripts in cells that will be induced to form the dorsal mesoderm, is consistent with the possibility that Xwnt-8b may be the endogenous agent that establishes asymmetry in the response of ectodermal cells to mesoderm-inducing signals, thereby initiating dorsal development. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|