Inducible gene expression in transgenic Xenopus embryos.
The amphibian Xenopus laevis has been successfully used for many years as a model system for studying vertebrate development. Because of technical limitations, however, molecular investigations have mainly concentrated on early stages. We have developed a straightforward method for stage-specific induction of gene expression in transgenic Xenopus embryos [1] [2]. This method is based on the Xenopus heat shock protein 70 (Xhsp70 [3]) promoter driving the expression of desired gene products. We found that ubiquitous expression of the transgene is induced upon relatively mild heat treatment. Green fluorescent protein (GFP) was used as a marker to monitor successful induction of gene expression in transgenic embryos. We used this method to study the stage specificity of Wnt signalling function. Transient ectopic Wnt-8 expression during early neurulation was sufficient to repress anterior head development and this capacity was restricted to early stages of neurulation. By transient over-expression at different stages of development, we show that frizzled-7 disrupted morphogenesis sequentially from anterior to posterior along the dorsal axis as development proceeds. These results demonstrate that this method for inducible gene expression in transgenic Xenopus embryos will be a very powerful tool for temporal analysis of gene function and for studying molecular mechanisms of vertebrate organogenesis.
Wheeler
G N
GN
Division of Cell and Developmental Biology, The Wellcome Trust Biocentre, University of Dundee, Dundee, DD1 5EH, UK.
Hamilton
F S
FS
Hoppler
S
S
D000818:Animals; D030801:Animals, Genetically Modified; D003598:Cytoskeletal Proteins; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D008164:Luminescent Proteins / Q000235:genetics; D010641:Phenotype; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics; D015398:Signal Transduction; D051153:Wnt Proteins; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics*; D029961:Zebrafish Proteins
D003598:Cytoskeletal Proteins; D018840:HSP70 Heat-Shock Proteins; D008164:Luminescent Proteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; D051153:Wnt Proteins; D029961:Zebrafish Proteins; C094521:wnt8a protein, zebrafish; D049452:Green Fluorescent Proteins