IAI FigSearch
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Caimano, M. J.
Right arrow Articles by Radolf, J. D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Caimano, M. J.
Right arrow Articles by Radolf, J. D.

Infection and Immunity, March 2000, p. 1574-1586, Vol. 68, No. 3
0019-9567/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

Molecular and Evolutionary Characterization of the cp32/18 Family of Supercoiled Plasmids in Borrelia burgdorferi 297

Melissa J. Caimano,1 Xiaofeng Yang,2 Taissia G. Popova,2 Michael L. Clawson,1 Darrin R. Akins,3 Michael V. Norgard,2 and Justin D. Radolf1,4,5,*

Center for Microbial Pathogenesis1 and Departments of Medicine4 and Microbiology,5 University of Connecticut Health Center, Farmington, Connecticut 06030; Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas 75235;2 and Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 731903

Received 20 September 1999/Returned for modification 17 November 1999/Accepted 26 November 1999

In this study, we characterized seven members of the cp32/18 family of supercoiled plasmids in Borrelia burgdorferi 297. Complete sequence analysis of a 21-kb plasmid (cp18-2) confirmed that the strain 297 plasmids are similar in overall content and organization to their B31 counterparts. Of the 31 open reading frames (ORFs) in cp18-2, only three showed sequence relatedness to proteins with known functions, and only one, a ParA/SopA ortholog, was related to nonborrelial polypeptides. Besides the lipoproteins, none of the ORFs appeared likely to encode a surface-exposed protein. Comparison with the B31 genomic sequence indicated that paralogs for most of the ORFs in cp18-2 can be identified on other genetic elements. cp18-2 was found to lack a 9- to 10-kb fragment present in the 32-kb homologs which, by extrapolation from the B31 cp32 sequences, contains at least 15 genes presumed to be unnecessary for plasmid maintenance. Sequence analysis of the lipoprotein-encoding variable loci provided evidence that recombinatorial processes within these regions may result in the acquisition of exogenous DNA. Pairwise analysis with random shuffling revealed that the multiple lipoproteins (Mlp; formerly designated 2.9 LPs) fall into two distinct homology groups which appear to have arisen by gene fusion events similar to those recently proposed to have generated the three OspE, OspF, and Elp lipoprotein families (D. R. Akins, M. J. Caimano, X. Yang, F. Cerna, M. V. Norgard, and J. D. Radolf, Infect. Immun. 67:1526-1532, 1999). Comparative analysis of the variable regions also indicated that recombination within the loci of each plasmid may occur independently. Last, comparison of variable loci revealed that the cp32/18 plasmid complements of the B31 and 297 isolates differ substantially, indicating that the two strains have been subject to divergent adaptive pressures. In addition to providing evidence for two different types of recombinatorial events involving cp32/18 plasmids, these findings underscore the need for genetic analysis of diverse borrelial isolates in order to elucidate the Lyme disease spirochete's complex parasitic strategies.

* Corresponding author. Mailing address: Center for Microbial Pathogenesis, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT 06030-3710. Phone: (860) 679-8129. Fax: (860) 679-8130. E-mail: JRadolf{at}up.uchc.edu.

Infection and Immunity, March 2000, p. 1574-1586, Vol. 68, No. 3
0019-9567/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 2000 by the American Society for Microbiology. All rights reserved.