Mechanisms of replication fork restart in Escherichia coli

Replication of the genome is crucial for the accurate transmission of genetic information. It has become clear over the last decade that the orderly progression of replication forks in both prokaryotes and eukaryotes is disrupted with high frequency by encounters with various obstacles either on or in the template strands. Survival of the organism then becomes dependent on both removal of the obstruction and resumption of replication. This latter point is particularly important in bacteria, where the number of replication forks per genome is nominally only two. Replication restart in Escherichia coli is accomplished by the action of the restart primosomal proteins, which use both recombination intermediates and stalled replication forks as substrates for loading new replication forks. These reactions have been reconstituted with purified recombination and replication proteins.