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Titration of the Escherichia coli DnaA protein to excess datA sites causes destabilization of replication forks, delayed replication initiation and delayed cell division
Author(s) -
LøbnerOlesen Anders,
Skarstad Kirsten
Publication year - 2003
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2003.03695.x
Subject(s) - dnaa , biology , dnab helicase , pre replication complex , ter protein , cell division , replication factor c , dna replication , origin of replication , replication (statistics) , origin recognition complex , genetics , seqa protein domain , control of chromosome duplication , microbiology and biotechnology , gene , cell , eukaryotic dna replication , helicase , virology , rna
Summary In Escherichia coli , the level of the initiator protein DnaA is limiting for initiation of replication at oriC . A high‐affinity binding site for DnaA, datA , plays an important role. Here, the effect of extra datA sites was studied. A moderate increase in datA dosage (≈ fourfold) delayed initiation of replication and cell division, but increased the rate of replication fork movement about twofold. At a further increase in the datA gene dosage, the SOS response was induced, and incomplete rounds of chromosome replication were detected. Overexpression of DnaA protein suppressed the SOS response and restored normal replication timing and rate of fork movement. In the presence of extra datA sites, cells showed a dependency on PriA and RecA proteins, indicating instability of the replication fork. The results suggest that wild‐type replication fork progression normally includes controlled pausing, and that this is a prerequisite for normal replication fork function.