Is RecG a general guardian of the bacterial genome?
The RecG protein of Escherichia coli is a double-stranded DNA translocase that unwinds a variety of branched DNAs in vitro, including Holliday junctions, replication forks, D-loops and R-loops. Coupled with the reported pleiotropy of recG mutations, this broad range of potential targets has made it hard to pin down what the protein does in vivo, though roles in recombination and replication fork repair have been suggested. However, recent studies suggest that RecG provides a more general defence against pathological DNA replication. We have postulated that this is achieved through the ability of RecG to eliminate substrates that the replication restart protein, PriA, could otherwise exploit to re-replicate the chromosome. Without RecG, PriA triggers a cascade of events that interfere with the duplication and segregation of chromosomes. Here we review the studies that led us to this idea and to conclude that RecG may be both a specialist activity and a general guardian of the genome.
Rudolph
Christian J
CJ
Institute of Genetics, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, United Kingdom.
Upton
Amy L
AL
Briggs
Geoffrey S
GS
Lloyd
Robert G
RG
D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D004265:DNA Helicases / Q000737:chemistry / Q000378:metabolism*; D004261:DNA Replication; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016680:Genome, Bacterial; D006801:Humans; D011995:Recombination, Genetic
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004265:DNA Helicases