Site-specific insertion of genes into integrons: role of the 59-base element and determination of the recombination cross-over point

Mol Microbiol. 1991 Aug;5(8):1941-59. doi: 10.1111/j.1365-2958.1991.tb00817.x.


From examination of published DNA sequences of genes found inserted at a specific site in integrons, all genes are shown to be associated, at their 3' ends, with a short imperfect inverted repeat sequence, a 59-base element or relative of this element. The similarity of the arrangement of gene inserts in the integron and in the Tn7 transposon family is described. A refined consensus for the 59-base element is reported. Members of this family are highly diverged and the relationship of a group of longer elements to the 59-base elements is demonstrated. The ability of 59-base elements of different length and sequence to act as sites for recombination catalysed by the integron-encoded DNA integrase is demonstrated, confirming that elements of this family have a common function. The ability of elements located between gene pairs to act as recombination sites has also been demonstrated. The recombination cross-over point has been localized to the GTT triplet which is conserved in the core sites, GTTRRRY, found at the 3' end of 59-base elements. Recombination at the core site found in inverse orientation at the 5' end of the 59-base elements was not detected, and the sequences responsible for orientation of the recombination event appear to reside within the 59-base element. A model for site-specific insertion of genes into integrons and Tn7-like transposons is proposed. Circular units consisting of a gene associated with a 59-base element are inserted into an ancestral element which contains neither a gene nor a 59-base element.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Consensus Sequence / genetics*
  • DNA Nucleotidyltransferases / metabolism
  • DNA Transposable Elements / genetics*
  • Escherichia coli / genetics
  • Integrases
  • Models, Genetic
  • Molecular Sequence Data
  • Mutagenesis, Insertional / genetics
  • Mutagenesis, Site-Directed / genetics
  • Plasmids / genetics
  • Recombination, Genetic / genetics*
  • Repetitive Sequences, Nucleic Acid / genetics*


  • DNA Transposable Elements
  • DNA Nucleotidyltransferases
  • Integrases

Associated data

  • GENBANK/M95287
  • GENBANK/X52364
  • GENBANK/X52365
  • GENBANK/X52366
  • GENBANK/X52367
  • GENBANK/X52368
  • GENBANK/X52369
  • GENBANK/X52370
  • GENBANK/X52371
  • GENBANK/X52372