Interchangeable Parts of the Escherichia coli Recombination Machinery

Amundsen, Susan K.; Smith, Gerald R.

doi:10.1016/s0092-8674(03)00197-1

Cited by 92 publications

(81 citation statements)

References 19 publications

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“…RecBCD unwinds and resects duplex DNA ends and loads RecA at a 39 ssDNA overhang created after the enzyme activity has been modulated at a x-sequence. The 39 end of the exposed strand may be held within the RecBCD complex, protecting it from other nucleases, while RecB's helicase activity may strip away any SSB protein (Kowalczykowski 2000;Amundsen and Smith 2003;Singleton et al 2004). The RecFOR proteins normally load RecA at ssDNA gaps.…”

Section: Resultsmentioning

confidence: 99%

RecG Protein and Single-Strand DNA Exonucleases Avoid Cell Lethality Associated With PriA Helicase Activity inEscherichia coli

et al. 2010

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Replication of the Escherichia coli chromosome usually initiates at a single origin (oriC) under control of DnaA. Two forks are established and move away in opposite directions. Replication is completed when these meet in a broadly defined terminus area half way around the circular chromosome. RecG appears to consolidate this arrangement by unwinding D-loops and R-loops that PriA might otherwise exploit to initiate replication at other sites. It has been suggested that without RecG such replication generates 39 flaps as the additional forks collide and displace nascent leading strands, providing yet more potential targets for PriA. Here we show that, to stay alive, cells must have either RecG or a 39 single-stranded DNA (ssDNA) exonuclease, which can be exonuclease I, exonuclease VII, or SbcCD. Cells lacking all three nucleases are inviable without RecG. They also need RecA recombinase and a Holliday junction resolvase to survive rapid growth, but SOS induction, although elevated, is not required. Additional requirements for Rep and UvrD are identified and linked with defects in DNA mismatch repair and with the ability to cope with conflicts between replication and transcription, respectively. Eliminating PriA helicase activity removes the requirement for RecG. The data are consistent with RecG and ssDNA exonucleases acting to limit PriA-mediated re-replication of the chromosome and the consequent generation of linear DNA branches that provoke recombination and delay chromosome segregation.

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Section: Resultsmentioning

confidence: 99%

RecG Protein and Single-Strand DNA Exonucleases Avoid Cell Lethality Associated With PriA Helicase Activity inEscherichia coli

et al. 2010

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“…3 This suggests a common need for ATP-dependent exonucleases and helicases in DNA metabolism and raises the possibility that the gene products from different organisms might be interchangeable (10). Clearly, H. pylori AddAB has nuclease activity in E. coli (Table 1 and Ref.…”

Section: Discussionmentioning

confidence: 99%

“…The initiation or presynaptic steps of recombination at dsDNA breaks in most bacteria involves the coordinated action of nuclease and helicase activities provided by one of two multisubunit enzymes, the AddAB and RecBCD enzymes (10). Escherichia coli recBCD null mutants have reduced cell viability, are hypersensitive to DNA-damaging agents, and are homologous recombination-deficient (11)(12)(13)(14).…”

mentioning

confidence: 99%

Dual Nuclease and Helicase Activities of Helicobacter pylori AddAB Are Required for DNA Repair, Recombination, and Mouse Infectivity

Amundsen

Fero

Salama

et al. 2009

Journal of Biological Chemistry

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Helicobacter pylori infection of the human stomach is associated with disease-causing inflammation that elicits DNA damage in both bacterial and host cells. NUC showed partial attenuation. E. coli ⌬recBCD expressing H. pylori addAB was recombination-deficient unless H. pylori recA was also expressed, suggesting a species-specific interaction between AddAB and RecA and also that H. pylori AddAB participates in both DNA repair and recombination. These results support a role for both the AddAB nuclease and helicase in DNA repair and promoting infectivity.

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“…Bacterial recombination is a complex pathway involving more than 40 enzymes, and is divided into four steps: initiation, strand exchange, migration of the Holliday junction and its resolution, with the possible participation of many alternative enzymes in each step (Amundsen and Smith, 2003). M. synoviae has a reduced recombinational apparatus, with only seven of the classical enzymes.…”

mentioning

confidence: 99%

“…The initiation pathways RecBCD and RecFOR are incomplete . These complexes are involved with RecA loading and stabilization in alternative pathways (Amundsen and Smith, 2003). RecA protein plays a pivotal role in this process.…”

mentioning

confidence: 99%

A model for the RecA protein of Mycoplasma synoviae

et al. 2007

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In this work, we predict a structural model for the RecA protein from M. synoviae (MsRecA) by theoretical homology modeling and evaluate the occurrence of polymorphisms in this protein within several isolates of this species. The structural model suggested for MsRecA conserves the main domains present in MtRecA and EcRecA. The L1 and L2 regions showed six and three amino acid substitutions, respectively, which apparently do not affect the conformation and function of MsRecA. The C-terminal domain is shorter than that found in EcRecA and MtRecA, which may increase its capacity to bind dsDNA and displace SSB, compensating the absence of recombination initiation enzymes. The MS59 isolate RecA sequence showed one polymorphism which does not affect its functions since these belong to the same physical-chemical group.

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Interchangeable Parts of the Escherichia coli Recombination Machinery

Cited by 92 publications

References 19 publications

RecG Protein and Single-Strand DNA Exonucleases Avoid Cell Lethality Associated With PriA Helicase Activity inEscherichia coli

RecG Protein and Single-Strand DNA Exonucleases Avoid Cell Lethality Associated With PriA Helicase Activity inEscherichia coli

Dual Nuclease and Helicase Activities of Helicobacter pylori AddAB Are Required for DNA Repair, Recombination, and Mouse Infectivity

A model for the RecA protein of Mycoplasma synoviae

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