Abstract
Replication arrest leads to the occurrence of DNA double-stranded breaks (DSB). We studied the mechanism of DSB formation by direct measure of the amount of in vivo linear DNA in Escherichia coli cells that lack the RecBCD recombination complex and by genetic means. The RuvABC proteins, which catalyze migration and cleavage of Holliday junctions, are responsible for the occurrence of DSBs at arrested replication forks. In cells proficient for RecBC, RuvAB is uncoupled from RuvC and DSBs may be prevented. This may be explained if a Holliday junction forms upon replication fork arrest, by annealing of the two nascent strands. RecBCD may act on the double-stranded tail prior to the cleavage of the RuvAB-bound junction by RuvC to rescue the blocked replication fork without breakage.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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DNA Helicases / genetics
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DNA Replication / physiology*
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DNA, Bacterial / metabolism*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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DnaB Helicases
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Electrophoresis, Gel, Pulsed-Field
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Endodeoxyribonucleases / genetics
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Endodeoxyribonucleases / metabolism
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Escherichia coli / genetics
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Escherichia coli / metabolism*
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Escherichia coli Proteins*
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Exodeoxyribonuclease V
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Exodeoxyribonucleases / genetics
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Exodeoxyribonucleases / metabolism
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Models, Biological
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Multienzyme Complexes / genetics
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Multienzyme Complexes / metabolism
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Mutation
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Phenotype
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Rec A Recombinases / genetics
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Recombination, Genetic / physiology*
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Temperature
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Trans-Activators / genetics
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Ultraviolet Rays
Substances
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Bacterial Proteins
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DNA, Bacterial
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DNA-Binding Proteins
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Escherichia coli Proteins
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Multienzyme Complexes
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RuvB protein, Bacteria
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Trans-Activators
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replication initiator protein
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ruvC protein, E coli
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Rec A Recombinases
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Endodeoxyribonucleases
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Exodeoxyribonucleases
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Exodeoxyribonuclease V
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exodeoxyribonuclease V, E coli
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Holliday junction DNA helicase, E coli
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DNA Helicases
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DnaB Helicases