Region-specific activation of the Xenopus Brachyury promoter involves active repression in ectoderm and endoderm: a study using transgenic frog embryos
| Autor: | Branko V. Latinkić, Walter Lerchner, Jacques E. Remacle, Danny Huylebroeck, James C. Smith |
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| Rok vydání: | 2000 |
| Předmět: |
Fetal Proteins
Brachyury Mesoderm Embryo Nonmammalian animal structures Xenopus Green Fluorescent Proteins Molecular Sequence Data Repressor Ectoderm Biology Animals Genetically Modified Xbra Genes Reporter Morphogenesis medicine Animals Promoter Regions Genetic Molecular Biology Genetics Binding Sites Base Sequence Endoderm Embryogenesis Gene Expression Regulation Developmental TATA Box Gastrulation Luminescent Proteins medicine.anatomical_structure embryonic structures T-Box Domain Proteins Transcription Factors Developmental Biology |
| Zdroj: | Europe PubMed Central |
| ISSN: | 1477-9129 0950-1991 |
| DOI: | 10.1242/dev.127.12.2729 |
| Popis: | Tissue specification in the early embryo requires the integration of spatial information at the promoters of developmentally important genes. Although several response elements for signalling pathways have been identified in Xenopus promoters, it is not yet understood what defines the sharp borders that restrict expression to a specific tissue. Here we use transgenic frog embryos to study the spatial and temporal regulation of the Xbra promoter. Deletion analysis and point mutations in putative transcription factor-binding sites identified two repressor modules, which exert their main effects at different stages during gastrulation. One module is defined by a bipartite binding site for a Smad-interacting protein (SIP1) of the δEF1 repressor family and acts to confine expression to the marginal zone early in gastrulation. The other module is defined by two homeodomain-binding sites and is responsible for repression in dorsal mesoderm and ectoderm at mid-gastrula stages. In addition, an upstream region of the promoter is necessary to repress expression in neural tissues later in development. Together, our results show that repression plays an important role in the restriction of Xbra expression to the mesoderm, and we suggest that similar mechanisms may be involved in the spatial regulation of other genes in early embryonic development. |
| Databáze: | OpenAIRE |
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