title: Homology throughout the multiple 32-kilobase circular plasmids present in Lyme disease spirochetes.
abstract: We have characterized seven different 32-kb circular plasmids carried by Borrelia burgdorferi isolate B31. Restriction endonuclease recognition site mapping and partial sequencing of these plasmids indicated that all seven are probably closely related to each other throughout their lengths and have substantial relationships to cp8.3, an 8.3-kb circular plasmid of B. burgdorferi sensu lato isolate Ip21. With the addition of the seven 32-kb plasmids, this bacterial strain is known to carry at least 10 linear and 9 circular plasmids. Variant cultures of B. burgdorferi B31 lacking one or more of the 32-kb circular plasmids are viable and, at least in some cases, infectious. We have examined a number of different natural isolates of Lyme disease borreliae and found that all of the B. burgdorferi sensu stricto isolates and most of the B. burgdorferi sensu lato isolates tested appear to carry multiple 32-kb circular plasmids related to those of B. burgdorferi B31. The ubiquity of these plasmids suggests that they may be important in the natural life cycle of these organisms. They may be highly conjugative plasmids or prophage genomes, which could prove to be useful in genetically manipulating B. burgdorferi.
authors.affiliation: Department of Oncological Sciences, University of Utah, Salt Lake City 84132, USA. casjens@bioscience.utah.edu
authors.forename: S
authors.initials: S
authors.lastname: Casjens
authors.forename: R
authors.initials: R
authors.lastname: van Vugt
authors.forename: K
authors.initials: K
authors.lastname: Tilly
authors.forename: P A
authors.initials: PA
authors.lastname: Rosa
authors.forename: B
authors.initials: B
authors.lastname: Stevenson
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D015748:Borrelia burgdorferi Group / Q000235:genetics*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016366:Open Reading Frames / Q000235:genetics; D010957:Plasmids / Q000737:chemistry / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001425:Bacterial Outer Membrane Proteins