Linear plasmids of Borrelia burgdorferi have a telomeric structure and sequence similar to those of a eukaryotic virus.

ABSTRACT The Lyme disease agent Borrelia burgdorferi maintains both linear and circular plasmids that appear to be essential for mammalian infection. Recent studies have characterized the circular plasmid regions that confer autonomous replication, but the genetic elements necessary for linear plasmid maintenance have not been experimentally identified. Two vectors derived from linear plasmids lp25 and lp28-1 were constructed and shown to replicate autonomously in B. burgdorferi. These vectors identify internal regions of linear plasmids necessary for autonomous replication in B. burgdorferi. Although derived from linear plasmids, the vectors are maintained in circular form in B. burgdorferi, indicating that plasmid maintenance functions are conserved, regardless of DNA form. Finally, derivatives of these vectors indicate that paralogous gene family 49 is apparently not required for either circular or linear plasmid replication.

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Telomere Exchange between Linear Replicons of Borrelia burgdorferi

Journal of Bacteriology ◽

10.1128/jb.186.13.4134-4141.2004 ◽

2004 ◽

Vol 186 (13) ◽

pp. 4134-4141 ◽

Cited By ~ 28

Author(s):

Wai Mun Huang ◽

Margaret Robertson ◽

John Aron ◽

Sherwood Casjens

Keyword(s):

Borrelia Burgdorferi ◽

Large Fraction ◽

Genetic Material ◽

Linear Plasmid ◽

Large Chromosome ◽

Evolutionary Time ◽

Linear Plasmids ◽

Nonhomologous Recombination ◽

Natural Isolates ◽

The Right

ABSTRACT Spirochetes in the genus Borrelia carry a linear chromosome and numerous linear plasmids that have covalently closed hairpin telomeres. The overall organization of the large chromosome of Borrelia burgdorferi appears to have been quite stable over recent evolutionary time; however, a large fraction of natural isolates carry differing lengths of DNA that extend the right end of the chromosome between about 7 and 20 kbp relative to the shortest chromosomes. We present evidence here that a rather recent nonhomologous recombination event in the B. burgdorferi strain Sh-2-82 lineage has replaced its right chromosomal telomere with a large portion of the linear plasmid lp21, which is present in the strain B31 lineage. At least two successive rounds of addition of linear plasmid genetic material to the chromosomal right end appear to have occurred at the Sh-2-82 right telomere, suggesting that this is an evolutionary mechanism by which plasmid genetic material can become part of the chromosome. The unusual nonhomologous nature of this rearrangement suggests that, barring horizontal transfer, it can be used as a unique genetic marker for this lineage of B. burgdorferi chromosomes.

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Purification and Ultrastructural Analysis of Terminal Sequences from the Cross-Linked, Linear Plasmids of Borrelia Burgdorferi

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158182 ◽

1990 ◽

Vol 48 (3) ◽

pp. 128-129

Author(s):

Lori L. Lubke ◽

Claude F. Garon

Keyword(s):

Electron Microscopy ◽

United States ◽

Borrelia Burgdorferi ◽

Methyl Mercury ◽

The United States ◽

Linear Plasmids ◽

Circular Dna ◽

Restriction Fragments ◽

Ion Exchange Column ◽

Alkaline Denaturation

Lyme borreliosis is now the most common arthropod-borne disease in the United States. Borrelia burgdorferi, the causative agent, has been isolated from humans, mammals, birds and arthropods and is cultivable in the laboratory. Careful structural analysis of the DNA content of several isolates has revealed, in addition to a 900 kb linear genome, a unique collection of crosslinked linear and covalently closed, circular DNA molecules ranging from 2-50 kb in length. While all of the linear species were shown to rapidly reanneal to linear duplexes after alkaline denaturation, single-stranded circular molecules measuring twice the length of the linears could be produced by treatment with methyl mercury, glyoxal and urea prior to mounting for electron microscopy. This rapid reannealing mediated by the terminal sequences of the molecule was used in a unique ion exchange column chromatography system to purify terminal, restriction fragments from any which originate internally. Purified terminal fragments could then be compared and characterized further by conventional methods.

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Decreased Electroporation Efficiency in Borrelia burgdorferi Containing Linear Plasmids lp25 and lp56: Impact on Transformation of Infectious B. burgdorferi

Infection and Immunity ◽

10.1128/iai.70.9.4798-4804.2002 ◽

2002 ◽

Vol 70 (9) ◽

pp. 4798-4804 ◽

Cited By ~ 70

Author(s):

Matthew B. Lawrenz ◽

Hiroki Kawabata ◽

Joye E. Purser ◽

Steven J. Norris

Keyword(s):

Sequence Analysis ◽

Borrelia Burgdorferi ◽

Shuttle Vector ◽

Kanamycin Resistance ◽

Linear Plasmids ◽

Selective Transformation ◽

Transformation Rates ◽

High Transformation ◽

Electroporation Efficiency

ABSTRACT The presence of the linear plasmids lp25 and lp56 of Borrelia burgdorferi B31 was found to dramatically decrease the rate of transformation by electroporation with the shuttle vector pBSV2, an autonomously replicating plasmid that confers kanamycin resistance (P. E. Stewart, R. Thalken, J. L. Bono, and P. Rosa, Mol. Microbiol. 39:714-721, 2001). B. burgdorferi B31 clones had transformation efficiencies that were either low, intermediate, or high, and this phenotype correlated with the presence or absence of lp25 and lp56. Under the conditions utilized in this study, no transformants were detected in clones that contained both lp25 and lp56; the few kanamycin-resistant colonies isolated did not contain pBSV2, indicating that the resistance was due to mutation. Intermediate electroporation rates (10 to 200 colonies per μg of DNA) were obtained with B31 clones that were either lp25− and lp56+ or lp25+ and lp56−. Clones in this group that initially contained lp25 lacked this plasmid in pBSV2 transformants, a finding consistent with selective transformation of lp25− variants. High transformation rates (>1,000 colonies per μg of DNA) occurred in clones that lacked both lp25 and lp56. Sequence analysis indicated that lp25 and lp56 contain genes that may encode restriction and/or modification systems that could result in the low transformation rates obtained with strains containing these plasmids. The previously reported correlation between lp25 and infectivity in mice, coupled with the barrier lp25 presents to transformation, may explain the difficulty in obtaining virulent transformants of B. burgdorferi.

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Borrelia burgdorferi Linear Plasmid 28-3 Confers a Selective Advantage in an Experimental Mouse-Tick Infection Model

Infection and Immunity ◽

10.1128/iai.00219-13 ◽

2013 ◽

Vol 81 (8) ◽

pp. 2986-2996 ◽

Cited By ~ 6

Author(s):

Daniel P. Dulebohn ◽

Aaron Bestor ◽

Patricia A. Rosa

Keyword(s):

Borrelia Burgdorferi ◽

Selective Advantage ◽

Infection Model ◽

Linear Plasmids ◽

Content Type ◽

Tick Infection ◽

Experimental Mouse ◽

Segmented Genome ◽

Infectious Cycle

ABSTRACTBorrelia burgdorferi, the bacterium that causes Lyme disease, has a unique segmented genome consisting of numerous linear and circular plasmids and a linear chromosome. Many of these genetic elements have been found to encode factors critical forB. burgdorferito complete the infectious cycle. However, several plasmids remain poorly characterized, and their roles during infection withB. burgdorferihave not been elucidated. To more fully characterize the role of one of the four 28-kb linear plasmids, lp28-3, we generated strains specifically lacking lp28-3 and assayed the contribution of genes carried by lp28-3 toB. burgdorferiinfection. We found that lp28-3 does not carry any genes that are strictly required for infection of a mouse or tick and that lp28-3-deficient spirochetes are competent at causing a disseminated infection. Interestingly, spirochetes containing lp28-3 were at a selective advantage compared to lp28-3-deficient spirochetes when coinjected into a mouse, and this advantage was reflected in the population of spirochetes acquired by feeding ticks. Our data demonstrate that genes carried by lp28-3, although not essential, contribute to the fitness ofB. burgdorferiduring infection.

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Repeated DNA Sequences on Circular and Linear Plasmids of Borrelia Burgdorferi Sensu Lato

Lyme Borreliosis ◽

10.1007/978-1-4615-2415-1_36 ◽

1994 ◽

pp. 253-260 ◽

Cited By ~ 8

Author(s):

Wolfram R. Zückert ◽

Elisabeth Filipuzzi-Jenny ◽

Jennifer Meister-Turner ◽

Margaretha Stålhammar-Carlemalm ◽

Jürg Meyer

Keyword(s):

Borrelia Burgdorferi ◽

Dna Sequences ◽

Borrelia Burgdorferi Sensu Lato ◽

Repeated Dna ◽

Linear Plasmids ◽

Repeated Dna Sequences

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Comparative Genome Hybridization Reveals Substantial Variation among Clinical Isolates of Borrelia burgdorferi Sensu Stricto with Different Pathogenic Properties

Journal of Bacteriology ◽

10.1128/jb.00459-06 ◽

2006 ◽

Vol 188 (17) ◽

pp. 6124-6134 ◽

Cited By ~ 50

Author(s):

Darya Terekhova ◽

Radha Iyer ◽

Gary P. Wormser ◽

Ira Schwartz

Keyword(s):

Borrelia Burgdorferi ◽

Gene Order ◽

Sensu Stricto ◽

Genomic Diversity ◽

Clinical Isolates ◽

Comparative Genome Hybridization ◽

Linear Plasmids ◽

Comparative Genome ◽

Reading Frame ◽

Typing Methods

ABSTRACT Clinical and murine studies suggest that there is a differential pathogenicity of different genotypes of Borrelia burgdorferi, the spirochetal agent of Lyme disease. Comparative genome hybridization was used to explore the relationship between different genotypes. The chromosomes of all studied isolates were highly conserved (>93%) with respect to both sequence and gene order. Plasmid sequences were substantially more diverse. Plasmids lp54, cp26, and cp32 were present in all tested isolates, and their sequences and gene order were conserved. The majority of linear plasmids showed variation both in terms of presence among different isolates and in terms of sequence and gene order. The data strongly imply that all B. burgdorferi clinical isolates contain linear plasmids related to each other, but the structure of these replicons may vary substantially from isolate to isolate. These alterations include deletions and presumed rearrangements that are likely to result in unique plasmid elements in many isolates. There is a strong correlation between complete genome hybridization profiles and other typing methods, which, in turn, also correlate to differences in pathogenicity. Because there is substantially less variation in the chromosomal and circular plasmid portions of the genome, the major differences in open reading frame content and genomic diversity among isolates are linear plasmid driven.

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Distribution of Twelve Linear Extrachromosomal DNAs in Natural Isolates of Lyme Disease Spirochetes

Journal of Bacteriology ◽

10.1128/jb.182.9.2476-2480.2000 ◽

2000 ◽

Vol 182 (9) ◽

pp. 2476-2480 ◽

Cited By ~ 38

Author(s):

Nanette Palmer ◽

Claire Fraser ◽

Sherwood Casjens

Keyword(s):

Lyme Disease ◽

Borrelia Burgdorferi ◽

Type Strain ◽

Sensu Stricto ◽

Linear Plasmids ◽

Borrelia Garinii ◽

Natural Isolates ◽

Disease Agent ◽

Lyme Disease Agent ◽

Sequence Similarities

ABSTRACT We have analyzed a panel of independent North American isolates of the Lyme disease agent spirochete, Borrelia burgdorferi (sensu stricto), for the presence of linear plasmids with sequence similarities to the 12 linear plasmids present in theB. burgdorferi type strain, isolate B31. The frequency of similarities to probes from each of the 12 B31 plasmids varied from 13 to 100% in the strain panel examined, and these similarities usually reside on plasmids similar in size to the cognate B31 plasmid. Sequences similar to 5 of the 12 B31 plasmids were found in all of the isolates examined, and >66% of the panel members hybridized to probes from 4 other plasmids. Sequences similar to most of the B. burgdorferi B31 plasmid-derived DNA probes used were also found on linear plasmids in the related Eurasian Lyme agentsBorrelia garinii and Borrelia afzelii; however, some of these plasmids had uniform but substantially different sizes from their B. burgdorferi counterparts.

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