Differential requirement of Srs2 helicase and Rad51 displacement activities in replication of hairpin-forming CAG/CTG repeats
| Autor: | Ranjith P. Anand, Lauren Verra, Catherine H. Freudenreich, Laura Sloan, Jennifer Nguyen, Guy-Franck Richard, David Viterbo |
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| Přispěvatelé: | Tufts University [Medford], Génétique des génomes - Genetics of Genomes (UMR 3525), Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), Tufts University, National Institutes of Health [R01GM063066, P01GM105473 to C.H.F], Tufts Graduate Student Research Award (to J.N.), Association pour la Recherche contre le Cancer [ARC SFI20111203641 to G.-F.R]. Funding for open access charge: National Institutes of Health [GM105473 to C.H.F.]., Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
DNA Replication
0301 basic medicine Genome instability gel Saccharomyces cerevisiae Proteins Inverted Repeat Sequences Saccharomyces cerevisiae Genome Integrity Repair and Replication 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Control of chromosome duplication dna replication fork [SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry Molecular Biology/Genomics [q-bio.GN] Genetics Electrophoresis Gel Two-Dimensional nuclease DNA Fungal juberg-marsidi syndrome chromosome fragility molecule biology dna electrophoresis DNA Helicases Fungal genetics DNA replication Helicase adenosine triphosphatases DNA Replication Fork genomic stability genomic instability proliferating cell nuclear antigen recombination Exodeoxyribonucleases 030104 developmental biology chemistry two-dimensional trinucleotide repeats alleles biology.protein Rad51 Recombinase Genome Fungal genetic 030217 neurology & neurosurgery DNA Protein Binding |
| Zdroj: | Nucleic Acids Research Nucleic Acids Research, Oxford University Press, 2017, 45 (8), pp.4519-4531. ⟨10.1093/nar/gkx088⟩ Nucleic Acids Research, 2017, 45 (8), pp.4519-4531. ⟨10.1093/nar/gkx088⟩ |
| ISSN: | 0305-1048 1362-4962 |
| DOI: | 10.1093/nar/gkx088⟩ |
| Popis: | International audience; Trinucleotide repeats are a source of genome instability , causing replication fork stalling, chromosome fragility, and impaired repair. Specialized heli-cases play an important role in unwinding DNA structures to maintain genome stability. The Srs2 heli-case unwinds DNA hairpins, facilitates replication, and prevents repeat instability and fragility. However , since Srs2 is a multifunctional protein with he-licase activity and the ability to displace Rad51 re-combinase, it was unclear which functions were required for its various protective roles. Here, using SRS2 separation-of-function alleles, we show that in the absence of Srs2 recruitment to PCNA or in helicase-deficient mutants, breakage at a CAG/CTG repeat increases. We conclude that Srs2 interaction with PCNA allows the helicase activity to unwind fork-blocking CAG/CTG hairpin structures to prevent breaks. Independently of PCNA binding, Srs2 also displaces Rad51 from nascent strands to prevent recombination-dependent repeat expansions and contractions. By 2D gel electrophoresis, we detect two different kinds of structured interme-diates or joint molecules (JMs). Some JMs are Rad51-independent and exhibit properties of reversed forks, including being processed by the Exo1 nuclease. In addition, in a helicase-deficient mutant, Rad51-dependent JMs are detected, probably corresponding to recombination between sisters. These results clarify the many roles of Srs2 in facilitating replica-tion through fork-blocking hairpin lesions. |
| Databáze: | OpenAIRE |
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