Titration of the Escherichia coli DnaA protein to excess datA sites causes destabilization of replication forks, delayed replication initiation and delayed cell division

TY - JOUR

T1 - Titration of the Escherichia coli DnaA protein to excess datA sites causes destabilization of replication forks, delayed replication initiation and delayed cell division

AU - Morigen, null

AU - Løbner-Olesen, Anders

AU - Skarstad, Kirsten

PY - 2003/10

Y1 - 2003/10

N2 - 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 ( approximately 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.

AB - 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 ( approximately 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.

KW - Adenosine Triphosphatases/genetics

KW - Bacterial Outer Membrane Proteins

KW - Bacterial Proteins/metabolism

KW - Cell Division

KW - DNA Helicases/genetics

KW - DNA Replication

KW - DNA, Bacterial/metabolism

KW - DNA-Binding Proteins/metabolism

KW - Escherichia coli/cytology

KW - Escherichia coli Proteins/genetics

KW - Exodeoxyribonuclease V/genetics

KW - Gene Dosage

KW - Gene Expression Regulation, Bacterial

KW - Protein Binding

KW - Rec A Recombinases/genetics

KW - Replication Origin

KW - SOS Response (Genetics)

KW - Suppression, Genetic

KW - Transcription Factors/genetics

KW - Transformation, Bacterial

KW - Ultraviolet Rays

M3 - Journal article

C2 - 14507385

SN - 0950-382X

VL - 50

SP - 349

EP - 362

JO - Molecular Microbiology

JF - Molecular Microbiology

IS - 1

ER -