title: Small plasmids harboring qnrB19: a model for plasmid evolution mediated by site-specific recombination at oriT and Xer sites.
abstract: Plasmids pPAB19-1, pPAB19-2, pPAB19-3, and pPAB19-4, isolated from Salmonella and Escherichia coli clinical strains from hospitals in Argentina, were completely sequenced. These plasmids include the qnrB19 gene and are 2,699, 3,082, 2,989, and 2,702 nucleotides long, respectively, and they share extensive homology among themselves and with other previously described small qnrB19-harboring plasmids. The genetic environment of qnrB19 in all four plasmids is identical to that in these other plasmids and in transposons such as Tn2012, Tn5387, and Tn5387-like. Nucleotide sequence comparisons among these and previously described plasmids showed a variable region characterized by being flanked by an oriT locus and a Xer recombination site. We propose that this arrangement could play a role in the evolution of plasmids and present a model for DNA swapping between plasmid molecules mediated by site-specific recombination events at oriT and a Xer target site.
authors.affiliation: Center for Applied Biotechnology Studies, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, California, USA.
authors.forename: Tung
authors.initials: T
authors.lastname: Tran
authors.forename: Patricia
authors.initials: P
authors.lastname: Andres
authors.forename: Alejandro
authors.initials: A
authors.lastname: Petroni
authors.forename: Alfonso
authors.initials: A
authors.lastname: Soler-Bistué
authors.forename: Ezequiel
authors.initials: E
authors.lastname: Albornoz
authors.forename: Angeles
authors.initials: A
authors.lastname: Zorreguieta
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Reyes-Lamothe
authors.forename: David J
authors.initials: DJ
authors.lastname: Sherratt
authors.forename: Alejandra
authors.initials: A
authors.lastname: Corso
authors.forename: Marcelo E
authors.initials: ME
authors.lastname: Tolmasky
mesh_terms: D001118:Argentina; D001483:Base Sequence; D005075:Biological Evolution; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D004927:Escherichia coli Infections / Q000382:microbiology; D006801:Humans; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D012475:Salmonella / Q000235:genetics*; D012480:Salmonella Infections / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial