Transgenic Xenopus laevis embryos can be generated using φC31 integrase

Abstract

Bacteriophage φC31 encodes an integrase that can mediate the insertion of extrachromosomal DNA into genomic DNA. Here we show that the coinjection of mRNA encoding φC31 integrase with plasmid DNA encoding the green fluorescent protein (GFP) can be used to generate transgenic X. laevis embryos. Despite integration into the genome, appropriate promoter expression required modification of the reporter plasmid by bracketing the GFP reporter gene with tandem copies of the chicken β-globin 5′ HS4 insulator to relieve silencing owing to chromatin position effects. These experiments demonstrate that the integration of insulated gene sequences using φC31 integrase can be used to efficiently create transgenic embryos in X. laevis and may increase the practical use of φC31 integrase in other systems as well. © 2005 Nature Publishing Group.