title: Definition of the attI1 site of class 1 integrons.
abstract: Integron-encoded integrases recognize two distinct types of recombination site: attI sites, found in integrons, and members of the 59-base element (59-be) family, found in the integron-associated gene cassettes. The class 1 integron integrase, IntI1, catalyses recombination between attI1 and a 59-be, two 59-be, or two attI1 sites, but events involving two attI1 sites are less efficient than the reactions in which a 59-be participates. The full attI1 site is required for high-efficiency recombination with a 59-be site. It is 65 bp in length and includes a simple site, consisting of a pair of inversely oriented IntI1-binding domains, together with two further directly oriented IntI1-binding sites designated strong and weak. However, a smaller region that contains only the simple site is sufficient to support a lower level of recombination with a complete attI1 partner and the features that determine the orientation of attI1 reside within this region. An unusual reaction between the attI1 site and a 59-be appears to be responsible for the loss of the central region of a 59-be to create a potential fusion of two adjacent gene cassettes.
authors.affiliation: School of Biological Sciences, Macquarie University Sydney, NSW 2109, Australia2.|CSIRO Molecular Science, Sydney Laboratory, PO Box 184, North Ryde, NSW 1670, Australia1.
authors.forename: Sally R
authors.initials: SR
authors.lastname: Partridge
authors.affiliation: School of Biological Sciences, Macquarie University Sydney, NSW 2109, Australia2.|CSIRO Molecular Science, Sydney Laboratory, PO Box 184, North Ryde, NSW 1670, Australia1.
authors.forename: Gavin D
authors.initials: GD
authors.lastname: Recchia
authors.affiliation: School of Biological Sciences, Macquarie University Sydney, NSW 2109, Australia2.|CSIRO Molecular Science, Sydney Laboratory, PO Box 184, North Ryde, NSW 1670, Australia1.
authors.forename: Carol
authors.initials: C
authors.lastname: Scaramuzzi
authors.affiliation: CSIRO Molecular Science, Sydney Laboratory, PO Box 184, North Ryde, NSW 1670, Australia1.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Collis
authors.affiliation: School of Biological Sciences, Macquarie University Sydney, NSW 2109, Australia2.
authors.forename: H W
authors.initials: HW
authors.lastname: Stokes
authors.affiliation: CSIRO Molecular Science, Sydney Laboratory, PO Box 184, North Ryde, NSW 1670, Australia1.
authors.forename: Ruth M
authors.initials: RM
authors.lastname: Hall
mesh_terms: D001287:Attachment Sites, Microbiological / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D019426:Integrases / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011995:Recombination, Genetic; D017384:Sequence Deletion; D012689:Sequence Homology, Nucleic Acid
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial; D019426:Integrases