TY - JOUR
T1 - A bacterial genome in flux
T2 - The twelve linear and nine circular extrachromosomal DNAs in an infectious isolate of the Lyme disease spirochete Borrelia burgdorferi
AU - Casjens, Sherwood
AU - Palmer, Nanette
AU - Van Vugt, René
AU - Huang, Wai Mun
AU - Stevenson, Brian
AU - Rosa, Patricia
AU - Lathigra, Raju
AU - Sutton, Granger
AU - Peterson, Jeremy
AU - Dodson, Robert J.
AU - Haft, Daniel
AU - Hickey, Erin
AU - Gwinn, Michelle
AU - White, Owen
AU - Fraser, Claire M.
PY - 2000
Y1 - 2000
N2 - We have determined that Borrelia burgdorferi strain B31 MI carries 21 extrachromosomal DNA elements, the largest number known for any bacterium. Among these are 12 linear and nine circular plasmids, whose sequences total 610,694 bp. We report here the nucleotide sequence of three linear and seven circular plasmids (comprising 290,546 bp) in this infectious isolate. This completes the genome sequencing project for this organism; its genome size is 1,521,419 bp (plus about 2000 bp of undetermined telomeric sequences). Analysis of the sequence implies that there has been extensive and sometimes rather recent DNA rearrangement among a number of the linear plasmids. Many of these events appear to have been mediated by recombinational processes that formed duplications. These many regions of similarity are reflected in the fact that most plasmid genes are members of one of the genome's 161 paralogous gene families; 107 of these gene families, which vary in size from two to 41 members, contain at least one plasmid gene. These rearrangements appear to have contributed to a surprisingly large number of apparently non-functional pseudogenes, a very unusual feature for a prokaryotic genome. The presence of these damaged genes suggests that some of the plasmids may be in a period of rapid evolution. The sequence predicts 535 plasmid genes ≥ 300 bp in length that may be intact and 167 apparently mutationally damaged and/or unexpressed genes (pseudogenes). The large majority, over 90%, of genes on these plasmids have no convincing similarity to genes outside Borrelia, suggesting that they perform specialized functions.
AB - We have determined that Borrelia burgdorferi strain B31 MI carries 21 extrachromosomal DNA elements, the largest number known for any bacterium. Among these are 12 linear and nine circular plasmids, whose sequences total 610,694 bp. We report here the nucleotide sequence of three linear and seven circular plasmids (comprising 290,546 bp) in this infectious isolate. This completes the genome sequencing project for this organism; its genome size is 1,521,419 bp (plus about 2000 bp of undetermined telomeric sequences). Analysis of the sequence implies that there has been extensive and sometimes rather recent DNA rearrangement among a number of the linear plasmids. Many of these events appear to have been mediated by recombinational processes that formed duplications. These many regions of similarity are reflected in the fact that most plasmid genes are members of one of the genome's 161 paralogous gene families; 107 of these gene families, which vary in size from two to 41 members, contain at least one plasmid gene. These rearrangements appear to have contributed to a surprisingly large number of apparently non-functional pseudogenes, a very unusual feature for a prokaryotic genome. The presence of these damaged genes suggests that some of the plasmids may be in a period of rapid evolution. The sequence predicts 535 plasmid genes ≥ 300 bp in length that may be intact and 167 apparently mutationally damaged and/or unexpressed genes (pseudogenes). The large majority, over 90%, of genes on these plasmids have no convincing similarity to genes outside Borrelia, suggesting that they perform specialized functions.
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U2 - 10.1046/j.1365-2958.2000.01698.x
DO - 10.1046/j.1365-2958.2000.01698.x
M3 - Article
C2 - 10672174
AN - SCOPUS:0033975239
SN - 0950-382X
VL - 35
SP - 490
EP - 516
JO - Molecular Microbiology
JF - Molecular Microbiology
IS - 3
ER -