title: Genetic elements involved in Tn21 site-specific integration, a novel mechanism for the dissemination of antibiotic resistance genes.
abstract: Transposon Tn21 codes for a site-specific integration system, which is probably a novel recombination mechanism, responsible for the acquisition of resistance genes in this widespread family of transposons. Using insertion and deletion mutagenesis we have identified the genetic loci of the various recombination hot-spots (RHS) and of the gene product (the integrase) that catalyses the reaction. The site of recombination has been localized in two of the RHSs to the DNA sequence GTTAG, which is present at the 3' termini of a loosely conserved palindromic sequence of approximately 59 bp. This 59 bp sequence, which flanks the inserted genes in a number of naturally occurring transposons, is the only element required in cis for the recombination reaction.
authors.affiliation: Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Martinez
authors.forename: F
authors.initials: F
authors.lastname: de la Cruz
mesh_terms: D001483:Base Sequence; D002872:Chromosome Deletion; D004254:DNA Nucleotidyltransferases / Q000235:genetics; D004251:DNA Transposable Elements; D004352:Drug Resistance, Microbial / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D019426:Integrases; D008969:Molecular Sequence Data; D009154:Mutation; D011815:R Factors; D011995:Recombination, Genetic; D015183:Restriction Mapping
chemical_list: D004251:DNA Transposable Elements; D004254:DNA Nucleotidyltransferases; D019426:Integrases