Open AccessCircular and linear plasmids of Lyme disease spirochetes have extensive homology: characterization of a repeated DNA element
Author(s) -
Wolfram R. Zückert,
Jürg Meyer
Publication year - 1996
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.178.8.2287-2298.1996
Subject(s) - orfs , biology , plasmid , open reading frame , inverted repeat , borrelia burgdorferi , genetics , homology (biology) , direct repeat , dna , microbiology and biotechnology , gene , genome , peptide sequence , antibody
We have cloned three copies of a repeated DNA segment from Borrelia burgdorferi sensu stricto strain B31, present on both circular and linear plasmids of this and other B. burgdorferi sensu lato strains. The DNA sequences are characterized by a highly homologous segment containing two open reading frames (ORFs), ORF-A and ORF-B. Five additional ORFs can be found on the slightly less homologous flanking sequences: ORF-G on the opposite strand upstream of ORF-A, and ORF-C, ORF-D, ORF-E, and ORF-F downstream of ORF-B. The 4.6-kb-long element containing ORF-A through ORF-E is flanked by approximately 180-bp-long imperfect inverted repeats (IRs). The putative gene product of ORF-C displays homology to proteins involved in plasmid maintenance in a number of gram-positive and gram-negative bacteria. ORF-E features several short, highly homologous direct repeats. ORF-A, ORF-B, and ORF-D are homologous to three ORFs on a recently described 8.3-kb circular plasmid of Borrelia afzelii Ip21 that are flanked by similar IRs (J. J. Dunn, S. R. Buchstein, L.-L. Butler, S. Fisenne, D. S. Polin, B. N. Lade, and B. J. Luft, J. Bacteriol. 176:2706-2717,1994). ORF-C and ORF-E, however, are missing from this region on the Ip21 plasmid. Furthermore, the repeated DNA element as defined by the IRs is present in opposite orientations relative to the flanking sequences on the B31 and Ip21 plasmids.