The Escherichia coli UvrD helicase is essential for Tus removal during recombination-dependent replication restart from Ter sites.
Blocking replication forks in the Escherichia coli chromosome by ectopic Ter sites renders the RecBCD pathway of homologous recombination and SOS induction essential for viability. In this work, we show that the E. coli helicase II (UvrD) is also essential for the growth of cells where replication forks are arrested at ectopic Ter sites. We propose that UvrD is required for Tus removal from Ter sites. The viability of a SOS non-inducible Ter-blocked strain is fully restored by the expression of the two SOS-induced proteins UvrD and RecA at high level, indicating that these are the only two SOS-induced proteins required for replication across Ter/Tus complexes. Several observations suggest that UvrD acts in concert with homologous recombination and we propose that UvrD is associated with recombination-initiated replication forks and that it removes Tus when a PriA-dependent, restarted replication fork goes across the Ter/Tus complex. Finally, expression of the UvrD homologue from Bacilus subtilis PcrA restores the growth of uvrD-deficient Ter-blocked cells, indicating that the capacity to dislodge Tus is conserved in this distant bacterial species.
Bidnenko
Vladimir
V
Génétique Microbienne, Institut National de la Recherche Agronomique, Domaine de Vilvert, 78352 Jouy en Josas Cedex, France.
Lestini
Roxane
R
Michel
Bénédicte
B
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage / Q000235:genetics; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair / Q000235:genetics; D004261:DNA Replication / Q000235:genetics*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D008957:Models, Genetic; D009154:Mutation / Q000235:genetics; D011938:Rec A Recombinases / Q000235:genetics / Q000378:metabolism; D013014:SOS Response, Genetics / Q000235:genetics; D013728:Terminator Regions, Genetic / Q000235:genetics
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C084217:pcrA protein, Bacteria; C489236:tus protein, E coli; D011938:Rec A Recombinases; D004265:DNA Helicases