RecBCD, SbcCD and ExoI process a substrate created by convergent replisomes to complete DNA replication
| Autor: | Brian M. Wendel, Emma A. Weber, Charmain T. Courcelle, Nicklas A. Hamilton, Justin Courcelle |
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| Rok vydání: | 2019 |
| Předmět: |
DNA Replication
DNA Bacterial Exonucleases Exodeoxyribonuclease V Biology Microbiology Article 03 medical and health sciences chemistry.chemical_compound Plasmid Escherichia coli Molecular Biology 030304 developmental biology RecBCD Recombination Genetic 0303 health sciences 030306 microbiology Escherichia coli Proteins DNA replication Substrate (chemistry) Chromosome Chromosomes Bacterial Cell biology Rec A Recombinases chemistry Replisome bacteria Recombination DNA Plasmids |
| Zdroj: | Mol Microbiol |
| ISSN: | 1365-2958 |
| Popis: | The accurate completion of DNA replication on the chromosome requires RecBCD and structure specific SbcCD ExoI nucleases. However, the substrates and mechanism by which this reaction occurs remains unknown. Here we show that these completion enzymes operate on plasmid substrates containing two replisomes, but are not required for plasmids containing one replisome. Completion on the two-replisome plasmids requires RecBCD, but does not require RecA and no broken intermediates accumulate in its absence, indicating that the completion reaction occurs normally in the absence of any double strand breaks. Further, similar to the chromosome, we show that when the normal completion reaction is prevented, an aberrant RecA-mediated recombination process leads to amplifications that drives most of the instabilities associated with the two-replisome substrates. The observations imply that the substrate SbcCD, ExoI, and RecBCD act upon in vivo is created specifically by two convergent replisomes, and demonstrate that the function of RecBCD in completing replication is independent of double strand break repair, and likely arises from a failure to join the strands of the convergent replication forks. |
| Databáze: | OpenAIRE |
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