title: Tn21-specific structures in gram-negative bacteria from clinical isolates.
abstract: A total of 807 gram-negative clinical isolates were treated with five different probes: intragenic segments for the transposase gene tnpA; the resolvase gene tnpR; the modulator of the resolvase, tnpM; the integraselike factor gene tnpI; and a 20-mer oligonucleotide for the recombinational site of action for the integrase. A total of 8% of the isolates hybridized with all five Tn21-related probes, and another 11% represented transposons in which one or more of the tested genes were missing. This 11% included groups whose descriptions have been published as well as groups that have not yet been described. The not-yet-described groups include various deletion products and some precursor structures, as is predicted for the evolution of Tn21-like transposons. The integration system appears to be coupled with Tn21-like structures and yet independent from these structures, implying an independent evolution of this system from Tn21-like transposons. The structures were found with similar incidence levels in all species tested except Pseudomonas aeruginosa, for which a novel separate family of class II transposons has been described before.
authors.affiliation: Institut für Pharmazeutische Mikrobiologie, University Bonn, Germany.
authors.forename: M T
authors.initials: MT
authors.lastname: Zühlsdorf
authors.forename: B
authors.initials: B
authors.lastname: Wiedemann
mesh_terms: D001483:Base Sequence; D015152:Blotting, Northern; D015342:DNA Probes; D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D005798:Genes, Bacterial; D006090:Gram-Negative Bacteria / Q000201:enzymology / Q000235:genetics*; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology*; D006801:Humans; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D009841:Oligonucleotides / Q000032:analysis; D010957:Plasmids; D015183:Restriction Mapping; D045564:Transposon Resolvases
chemical_list: D015342:DNA Probes; D004269:DNA, Bacterial; D009841:Oligonucleotides; C473490:Tn21 resolvase; D045564:Transposon Resolvases