Recombinational DNA Repair: The RecF and RecR Proteins Limit the Extension of RecA Filaments beyond Single-Strand DNA Gaps

Webb, Brian; Cox, Michael M.; Inman, Ross B.

doi:10.1016/s0092-8674(00)80418-3

Cited by 179 publications

(162 citation statements)

References 57 publications

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“…RecO and RecR act together as mediators to overcome ssb-dependent inhibition of RecA-mediated strand exchange (38,39). A third protein, RecF, is likely to function with RecO, and RecR in vivo and has been shown to be capable of limiting the assembly of RecA to regions of ssDNA in vitro (40). Genetic studies provide evidence that RecF, RecO, and RecR function specifically during the repair of daughter strand gaps caused by the stalling of polymerase (6).…”

Section: Reca-like Recombinases Assemble On Single-strand Dna (Ssdna)mentioning

confidence: 99%

Assembly of RecA-like recombinases: Distinct roles for mediator proteins in mitosis and meiosis

Gasior

Olivares

Ear

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

158

125

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Members of the RecA family of recombinases from bacteriophage T4, Escherichia coli, yeast, and higher eukaryotes function in recombination as higher-order oligomers assembled on tracts of single-strand DNA (ssDNA). Biochemical studies have shown that assembly of recombinase involves accessory factors. These studies have identified a class of proteins, called recombination mediator proteins, that act by promoting assembly of recombinase on ssDNA tracts that are bound by ssDNA-binding protein (ssb). In the absence of mediators, ssb inhibits recombination reactions by competing with recombinase for DNA-binding sites. Here we briefly review mediated recombinase assembly and present results of new in vivo experiments. Immuno-double-staining experiments in Saccharomyces cerevisiae suggest that Rad51, the eukaryotic recombinase, can assemble at or near sites containing ssb (replication protein A, RPA) during the response to DNA damage, consistent with a need for mediator activity. Correspondingly, mediator gene mutants display defects in Rad51 assembly after DNA damage and during meiosis, although the requirements for assembly are distinct in the two cases. In meiosis, both Rad52 and Rad55͞57 are required, whereas either Rad52 or Rad55͞57 is sufficient to promote assembly of Rad51 in irradiated mitotic cells. Rad52 promotes normal amounts of Rad51 assembly in the absence of Rad55 at 30°C but not 20°C, accounting for the cold sensitivity of rad55 null mutants. Finally, we show that assembly of Rad51 is induced by radiation during S phase but not during G1, consistent with the role of Rad51 in repairing the spontaneous damage that occurs during DNA replication.H omologous recombination reactions promote repair of DNA ends formed by double-strand breaks (DSBs) and by replication fork collapse. Recombinational repair also allows cells to replicate past DNA lesions that block the progress of DNA polymerase. In phage T4, recombination is critical for initiating replication. In eukaryotes, homologous recombination is critical for accurate reductional segregation of chromosomes during meiosis. Finally, in prokaryotes, recombination allows horizontal transfer of alleles among and between bacteria and phage.At the center of homologous recombination are the recombinases, proteins that promote the formation of heteroduplex DNA. Of particular importance are the recombinases of the RecA family, including RecA in eubacteria, RadA in archea, Rad51 and Dmc1 in eukaryea, and the bacteriophage T4 UvsX protein.RecA-Like Recombinases Assemble on Single-Strand DNA (ssDNA).

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Section: Reca-like Recombinases Assemble On Single-strand Dna (Ssdna)mentioning

confidence: 99%

Assembly of RecA-like recombinases: Distinct roles for mediator proteins in mitosis and meiosis

Gasior

Olivares

Ear

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

158

125

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“…As mentioned above, the replication of damaged DNA templates results in daughter-strand gaps (16), providing a substrate for RecA binding (22). Since this discovery, it has been shown that purified E. coli RecA binds these gaps with the help of the RecFOR proteins (15,17).…”

mentioning

confidence: 97%

Replication is required for the RecA localization response to DNA damage in Bacillus subtilis

Simmons

Grossman

Walker

2007

Proc. Natl. Acad. Sci. U.S.A.

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In both prokaryotes and eukaryotes, proteins involved in DNA repair often organize into multicomponent complexes that can be visualized as foci in living cells. We used a RecA-GFP fusion to examine the subcellular cues that direct RecA-GFP to assemble as foci in response to DNA damage. We used two different methods to inhibit initiation of DNA replication and determined that DNA replication is required for the cell to establish RecA-GFP foci after exposure to DNA-damaging agents. Furthermore, use of endonuclease cleavage to generate a site-specific double-strand break demonstrated that the replication machinery (replisome) and DNA synthesis are required for assembly of RecA-GFP foci during repair of a double-strand break. We monitored the cellular levels of RecA and found that focus formation does not require further induction of protein levels, suggesting that foci result from a redistribution of existing protein to sites of damage encountered by the replisome. Taken together, our results support the model that existing RecA protein is recruited to ssDNA generated by the replisome at sites of DNA damage. These results provide insight into the mechanisms that the cell uses to recruit repair proteins to damaged DNA in living cells.replisome ͉ focus ͉ double-strand break

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“…coli RecF, RecO, and RecR proteins are well studied. The RecR protein plays a critical role in recombinational DNA repair by forming complexes with RecO or RecF (13)(14)(15). The RecOR complex facilitates RecA filament formation on SSB-coated ssDNA and prevents the dissociation of RecA from ssDNA ends (16).…”

mentioning

confidence: 99%

Identification of the RecR Toprim Domain as the Binding Site for both RecF and RecO

Honda

Inoue

Yoshimasu

et al. 2006

Journal of Biological Chemistry

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The RecR protein forms complexes with RecF or RecO that direct the specific loading of RecA onto gapped DNA. However, the binding sites of RecF and RecO on RecR have yet to be identified. In this study, a Thermus thermophilus RecR dimer model was constructed by NMR analysis and homology modeling. NMR titration analysis suggested that the hairpin region of the helix-hairpin-helix motif in the cavity of the RecR dimer is a binding site for double-stranded DNA (dsDNA) and that the acidic cluster region of the Toprim domain is a RecO binding site. Mutations of Glu-84, Asp-88, and Glu-144 residues comprising that acidic cluster were generated. The E144A and E84A mutations decreased the binding affinity for RecO, but the D88A did not. Interestingly, the binding ability to RecF was abolished by E144A, suggesting that the region surrounding the RecR Glu-144 residue could be a binding site not only for RecO but also for RecF. Furthermore, RecR and RecF formed a 4:2 heterohexamer in solution that was unaffected by adding RecO, indicating a preference by RecR for RecF over RecO. The RecFR complex is considered to be involved in the recognition of the dsDNA-ssDNA junction, whereas RecO binds single-stranded DNA (ssDNA) and ssDNA-binding protein. Thus, the RecR Toprim domain may contribute to the RecO interaction with RecFR complexes at the dsDNA-ssDNA junction site during recombinational DNA repair mediated by the RecFOR.Maintaining genomic integrity by repairing damaged DNA is crucial for all organisms. DNA damage can arise during normal DNA metabolism such as the introduction of mismatches during replication and the deamination of bases, or it can be caused by exposure to exogenous factors such as ultraviolet radiation, ␥-radiation, and chemical mutagens. Such DNA damage is mostly repaired by base excision repair, nucleotide excision repair, and mismatch repair pathways, based on information provided by the complementary strand in a damaged duplex. However, double-stranded DNA (dsDNA) 2 break and base lesions in single-stranded DNA (ssDNA) gap regions having no complementary strands can also arise, mainly during replication. To cope with this category of DNA damage, organisms have developed recombinational repair pathways that minimize the loss of genetic information by using homologous DNA as a template for repair.RecFOR and/or RecBCD pathways are required to initiate homologous DNA recombination in bacteria (1). The Escherichia coli RecFOR pathway is mainly used for ssDNA gap repair, whereas the RecBCD pathway is responsible for dsDNA break repair. However, the RecFOR pathway can also repair dsDNA breaks, as has been demonstrated in recBC sbcB mutants, which are deficient in the RecBCD pathway (2, 3). In the RecFOR pathway, dsDNA breaks are unwound by the RecQ helicase and processed by the RecJ 5Ј-to 3Ј-exonuclease, and the resulting 3Ј-tailed ssDNA is coated with the ssDNA-binding protein (SSB). The RecF, RecO, and RecR proteins then mediate the loading of RecA protein onto the SSB-coated ssDNA, specifically at junctio...

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Recombinational DNA Repair: The RecF and RecR Proteins Limit the Extension of RecA Filaments beyond Single-Strand DNA Gaps

Cited by 179 publications

References 57 publications

Assembly of RecA-like recombinases: Distinct roles for mediator proteins in mitosis and meiosis

Assembly of RecA-like recombinases: Distinct roles for mediator proteins in mitosis and meiosis

Replication is required for the RecA localization response to DNA damage in Bacillus subtilis

Identification of the RecR Toprim Domain as the Binding Site for both RecF and RecO

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