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A case for sliding SeqA tracts at anchored replication forks during Escherichia coli chromosome replication and segregation
Author(s) -
Brendler Therese,
Sawitzke Jim,
Sergueev Kirill,
Austin Stuart
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.22.6249
Subject(s) - seqa protein domain , biology , dna replication , dna , genetics , origin of replication , microbiology and biotechnology , dna binding protein , cell division , control of chromosome duplication , ter protein , escherichia coli , gene , cell , transcription factor
SeqA is an Escherichia coli DNA‐binding protein that acts at replication origins and controls DNA replication. However, binding is not exclusive to origins. Many fragments containing two or more hemi‐methylated GATC sequences bind efficiently. Binding was optimal when two such sequences were closely apposed or up to 31 bases apart on the same face of the DNA helix. Binding studies suggest that neighboring bound proteins contact each other to form a complex with the intervening DNA looped out. There are many potential binding sites distributed around the E.coli chromosome. As replication produces a transient wave of hemi‐methylation, tracts of SeqA binding are likely to associate with each fork as replication progresses. The number and positions of green fluorescent protein–SeqA foci seen in living cells suggest that they correspond to these tracts, and that the forks are tethered to planes of cell division. SeqA may help to tether the forks or to organize newly replicated DNA into a structure that aids DNA to segregate away from the replication machinery.