Replication Stalling and Heteroduplex Formation within CAG/CTG Trinucleotide Repeats by Mismatch Repair

Handle URI:
http://hdl.handle.net/10754/602087
Title:
Replication Stalling and Heteroduplex Formation within CAG/CTG Trinucleotide Repeats by Mismatch Repair
Authors:
Viterbo, David; Michoud, Gregoire ( 0000-0003-1071-9900 ) ; Mosbach, Valentine; Dujon, Bernard; Richard, Guy-Franck
Abstract:
Trinucleotide repeat expansions are responsible for at least two dozen neurological disorders. Mechanisms leading to these large expansions of repeated DNA are still poorly understood. It was proposed that transient stalling of the replication fork by the repeat tract might trigger slippage of the newly-synthesized strand over its template, leading to expansions or contractions of the triplet repeat. However, such mechanism was never formally proven. Here we show that replication fork pausing and CAG/CTG trinucleotide repeat instability are not linked, stable and unstable repeats exhibiting the same propensity to stall replication forks when integrated in a yeast natural chromosome. We found that replication fork stalling was dependent on the integrity of the mismatch-repair system, especially the Msh2p-Msh6p complex, suggesting that direct interaction of MMR proteins with secondary structures formed by trinucleotide repeats in vivo, triggers replication fork pauses. We also show by chromatin immunoprecipitation that Msh2p is enriched at trinucleotide repeat tracts, in both stable and unstable orientations, this enrichment being dependent on MSH3 and MSH6. Finally, we show that overexpressing MSH2 favors the formation of heteroduplex regions, leading to an increase in contractions and expansions of CAG/CTG repeat tracts during replication, these heteroduplexes being dependent on both MSH3 and MSH6. These heteroduplex regions were not detected when a mutant msh2-E768A gene in which the ATPase domain was mutated was overexpressed. Our results unravel two new roles for mismatch-repair proteins: stabilization of heteroduplex regions and transient blocking of replication forks passing through such repeats. Both roles may involve direct interactions between MMR proteins and secondary structures formed by trinucleotide repeat tracts, although indirect interactions may not be formally excluded.
KAUST Department:
Biological and Environmental Sciences and Engineering (BESE) Division
Citation:
Replication Stalling and Heteroduplex Formation within CAG/CTG Trinucleotide Repeats by Mismatch Repair 2016 DNA Repair
Publisher:
Elsevier BV
Journal:
DNA Repair
Issue Date:
16-Mar-2016
DOI:
10.1016/j.dnarep.2016.03.002
Type:
Article
ISSN:
15687864
Sponsors:
G.-F. R. thanks C. Saveanu and F. Feuerbach for the use of the TAP-tag library and advices on ChIP.
Additional Links:
http://linkinghub.elsevier.com/retrieve/pii/S156878641530104X
Appears in Collections:
Articles; Biological and Environmental Sciences and Engineering (BESE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorViterbo, Daviden
dc.contributor.authorMichoud, Gregoireen
dc.contributor.authorMosbach, Valentineen
dc.contributor.authorDujon, Bernarden
dc.contributor.authorRichard, Guy-Francken
dc.date.accessioned2016-03-17T13:18:35Zen
dc.date.available2016-03-17T13:18:35Zen
dc.date.issued2016-03-16en
dc.identifier.citationReplication Stalling and Heteroduplex Formation within CAG/CTG Trinucleotide Repeats by Mismatch Repair 2016 DNA Repairen
dc.identifier.issn15687864en
dc.identifier.doi10.1016/j.dnarep.2016.03.002en
dc.identifier.urihttp://hdl.handle.net/10754/602087en
dc.description.abstractTrinucleotide repeat expansions are responsible for at least two dozen neurological disorders. Mechanisms leading to these large expansions of repeated DNA are still poorly understood. It was proposed that transient stalling of the replication fork by the repeat tract might trigger slippage of the newly-synthesized strand over its template, leading to expansions or contractions of the triplet repeat. However, such mechanism was never formally proven. Here we show that replication fork pausing and CAG/CTG trinucleotide repeat instability are not linked, stable and unstable repeats exhibiting the same propensity to stall replication forks when integrated in a yeast natural chromosome. We found that replication fork stalling was dependent on the integrity of the mismatch-repair system, especially the Msh2p-Msh6p complex, suggesting that direct interaction of MMR proteins with secondary structures formed by trinucleotide repeats in vivo, triggers replication fork pauses. We also show by chromatin immunoprecipitation that Msh2p is enriched at trinucleotide repeat tracts, in both stable and unstable orientations, this enrichment being dependent on MSH3 and MSH6. Finally, we show that overexpressing MSH2 favors the formation of heteroduplex regions, leading to an increase in contractions and expansions of CAG/CTG repeat tracts during replication, these heteroduplexes being dependent on both MSH3 and MSH6. These heteroduplex regions were not detected when a mutant msh2-E768A gene in which the ATPase domain was mutated was overexpressed. Our results unravel two new roles for mismatch-repair proteins: stabilization of heteroduplex regions and transient blocking of replication forks passing through such repeats. Both roles may involve direct interactions between MMR proteins and secondary structures formed by trinucleotide repeat tracts, although indirect interactions may not be formally excluded.en
dc.description.sponsorshipG.-F. R. thanks C. Saveanu and F. Feuerbach for the use of the TAP-tag library and advices on ChIP.en
dc.language.isoenen
dc.publisherElsevier BVen
dc.relation.urlhttp://linkinghub.elsevier.com/retrieve/pii/S156878641530104Xen
dc.rightsNOTICE: this is the author’s version of a work that was accepted for publication in DNA Repair. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in DNA Repair, 16 March 2016. DOI: 10.1016/j.dnarep.2016.03.002en
dc.subjectReplication pauseen
dc.subjectTrinucleotide repeatsen
dc.subjectMismatch repairen
dc.subjectHeteroduplexen
dc.titleReplication Stalling and Heteroduplex Formation within CAG/CTG Trinucleotide Repeats by Mismatch Repairen
dc.typeArticleen
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
dc.identifier.journalDNA Repairen
dc.eprint.versionPost-printen
dc.contributor.institutionInstitut Pasteur, Unité de Génétique Moléculaire des Levures, Département Génomes & Génétique, 25 rue du Dr Roux, F-75015 Paris, Franceen
dc.contributor.institutionSorbonne Universités, UPMC Univ Paris 06, IFD, 4 Place Jussieu, 75252 Paris Cedex 05, Franceen
dc.contributor.institutionCNRS, UMR3525, F-75015 Paris, Franceen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorMichoud, Gregoireen
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