title: DNA damage-induced replication fork regression and processing in Escherichia coli.
abstract: DNA lesions that block replication are a primary cause of rearrangements, mutations, and lethality in all cells. After ultraviolet (UV)-induced DNA damage in Escherichia coli, replication recovery requires RecA and several other recF pathway proteins. To characterize the mechanism by which lesion-blocked replication forks recover, we used two-dimensional agarose gel electrophoresis to show that replication-blocking DNA lesions induce a transient reversal of the replication fork in vivo. The reversed replication fork intermediate is stabilized by RecA and RecF and is degraded by the RecQ-RecJ helicase-nuclease when these proteins are absent. We propose that fork regression allows repair enzymes to gain access to the replication-blocking lesion, allowing processive replication to resume once the blocking lesion is removed.
authors.affiliation: Department of Biological Sciences, Box GY, Mississippi State University, Mississippi State, MS 39762, USA. jcourcelle@biology.msstate.edu
authors.forename: Justin
authors.initials: J
authors.lastname: Courcelle
authors.forename: Janet R
authors.initials: JR
authors.lastname: Donaldson
authors.forename: Kin-Hoe
authors.initials: KH
authors.lastname: Chow
authors.forename: Charmain T
authors.initials: CT
authors.lastname: Courcelle
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage; D004265:DNA Helicases / Q000378:metabolism; D004260:DNA Repair; D004261:DNA Replication; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005090:Exodeoxyribonucleases / Q000378:metabolism; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000378:metabolism*; D011938:Rec A Recombinases / Q000235:genetics / Q000378:metabolism; D053484:RecQ Helicases; D014466:Ultraviolet Rays
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C081006:RecO protein, E coli; C489318:RecR protein, E coli; C489340:recF protein, E coli; C065831:RecR protein, Bacteria; C066218:recF protein, Bacteria; D011938:Rec A Recombinases; D005090:Exodeoxyribonucleases; C489467:RecJ protein, E coli; C070765:recJ protein, Bacteria; C068631:UvrA protein, E coli; D000251:Adenosine Triphosphatases; C506724:RecQ protein, E coli; D004265:DNA Helicases; D053484:RecQ Helicases