Statistics analysis of bacterial genomes allows prediction of various
motifs involved in chromosome organization, whose sequence is not
necessarily conserved from one species to another. One of these
motifs, KOPS (FtsK Orienting Polar Sequence) [1], is implicated in
chromosome dimer resolution. Formation of such dimers, in the
absence of a mechanism for resolution, may result in cell death. To
overcome this phenomenon, the Escherichia coli FtsK protein
translocates DNA to bring a specific region to the septum.
Recombination at this region then resolves the chromosome dimer,
thereby permitting the normal scission of the mother cell into two
daughter cells. The orientation of translocation is determined in a
sequence dependent manner through the recognition by FtsK of the
KOPS motif, the sequence of which has been characterized in E.
coli, Vibrio cholerae and Bacillus subtilis [1,2,3].
To define the KOPS sequence in Streptococcus and Lactococcus we used
these examples and determined the general properties of
KOPS. More precisely, we determined the statistical properties
related to KOPS location and orientation features needed for
recognition by FtsK: local and/or general over-representation,
orientation over-skew, absolute orientation skew, etc... We searched
for motifs with similar statistical properties in Lactococcus lactis,
Streptococcus pneumoniae and Streptococcus agalactiae. The
analysis indicated potential KOPS in these bacteria. The L. lactis
candidate, whose sequence is different from the known KOPS, was
validated experimentally. Thus, KOPS motifs were predicted from
exhaustive statistical analysis based on information obtained from
known other motifs. It would have been impossible to define them
only with experiments using currently available techniques as little is
known concerning FtsK/KOPS interactions.
[1] EMBO J. 2005 Nov 2;24(21):3770-80. Epub 2005 Oct 6.
KOPS: DNA motifs that control E. coli chromosome segregation by orienting the FtsK translocase.
Bigot S, Saleh OA, Lesterlin C, Pages C, El Karoui M, Dennis C, Grigoriev M, Allemand JF, Barre
FX, Cornet F.
[2] PLoS Genet. 2008 Sep 26;4(9):e1000201.
FtsK-dependent dimer resolution on multiple chromosomes in the pathogen Vibrio cholerae.
Val ME, Kennedy SP, El Karoui M, Bonné L, Chevalier F, Barre FX.
[3] Nat Struct Mol Biol. 2008 May;15(5):485-93. Epub 2008 Apr 6.
Sequence-directed DNA export guides chromosome translocation during sporulation in Bacillus
subtilis.
Ptacin JL, Nollmann M, Becker EC, Cozzarelli NR, Pogliano K, Bustamante C.
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