Cellular characterization of the primosome and rep helicase in processing and restoration of replication following arrest by UV-induced DNA damage in Escherichia coli.
Following arrest by UV-induced DNA damage, replication is restored through a sequence of steps that involve partial resection of the nascent DNA by RecJ and RecQ, branch migration and processing of the fork DNA surrounding the lesion by RecA and RecF-O-R, and resumption of DNA synthesis once the blocking lesion has been repaired or bypassed. In vitro, the primosomal proteins (PriA, PriB, and PriC) and Rep are capable of initiating replication from synthetic DNA fork structures, and they have been proposed to catalyze these events when replication is disrupted by certain impediments in vivo. Here, we characterized the role that PriA, PriB, PriC, and Rep have in processing and restoring replication forks following arrest by UV-induced DNA damage. We show that the partial degradation and processing of the arrested replication fork occurs normally in both rep and primosome mutants. In each mutant, the nascent degradation ceases and DNA synthesis initially resumes in a timely manner, but the recovery then stalls in the absence of PriA, PriB, or Rep. The results demonstrate a role for the primosome and Rep helicase in overcoming replication forks arrested by UV-induced damage in vivo and suggest that these proteins are required for the stability and efficiency of the replisome when DNA synthesis resumes but not to initiate de novo replication downstream of the lesion.
Department of Biology, Portland State University, Portland, Oregon, USA. charmc@pdx.edu
Charmain T
CT
Courcelle
Allison J
AJ
Landstrom
Brittany
B
Anderson
Justin
J
Courcelle
D004249:DNA Damage; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000378:metabolism; D004261:DNA Replication; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000502:physiology* / Q000528:radiation effects; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D014466:Ultraviolet Rays
D029968:Escherichia coli Proteins; D045643:DNA Repair Enzymes