title: Defining the plasmid-borne restriction-modification systems of the Lyme disease spirochete Borrelia burgdorferi.
abstract: The restriction-modification (R-M) systems of many bacteria present a barrier to the stable introduction of foreign DNA. The Lyme disease spirochete Borrelia burgdorferi has two plasmid-borne putative R-M genes, bbe02 and bbq67, whose presence limits transformation by shuttle vector DNA from Escherichia coli. We show that both the bbe02 and bbq67 loci in recipient B. burgdorferi limit transformation with shuttle vector DNA from E. coli, irrespective of its dam, dcm, or hsd methylation status. However, plasmid DNA purified from B. burgdorferi transformed naïve B. burgdorferi much more efficiently than plasmid DNA from E. coli, particularly when the bbe02 and bbq67 genotypes of the B. burgdorferi DNA source matched those of the recipient. We detected adenine methylation of plasmid DNA prepared from B. burgdorferi that carried bbe02 and bbq67. These results indicate that the bbe02 and bbq67 loci of B. burgdorferi encode distinct R-M enzymes that methylate endogenous DNA and cleave foreign DNA lacking the same sequence-specific modification. Our findings have basic implications for horizontal gene transfer among B. burgdorferi strains with distinct plasmid contents. Further characterization and identification of the nucleotide sequences recognized by BBE02 and BBQ67 will facilitate efficient genetic manipulation of this pathogenic spirochete.
authors.affiliation: Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA. regor@niaid.nih.gov
authors.forename: Ryan O M
authors.initials: RO
authors.lastname: Rego
authors.forename: Aaron
authors.initials: A
authors.lastname: Bestor
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Rosa
mesh_terms: D000818:Animals; D001483:Base Sequence; D025065:Borrelia burgdorferi / Q000378:metabolism*; D019175:DNA Methylation; D015280:DNA Restriction-Modification Enzymes / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D022761:Gene Transfer, Horizontal; D006801:Humans; D008193:Lyme Disease / Q000382:microbiology*; D051379:Mice; D008809:Mice, Inbred C3H; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids / Q000235:genetics / Q000378:metabolism*
chemical_list: D015280:DNA Restriction-Modification Enzymes; D004269:DNA, Bacterial