Abstract
Recombination induced by double-strand breaks (DSBs) in yeast leads to a higher proportion of expansions to contractions than does replication-associated tract length changes. Expansions are apparently dependent on the property of the repeat array to form hairpins, since DSB repair of a CAA(87) repeat induces only contractions of the repeat sequence. DSB-repair efficiency is reduced by 40% when DNA synthesis must traverse a CAG(98) array, as compared with a CAA(87) array. These data indicate that repair- associated DNA synthesis is inhibited by secondary structures formed by CAG(98) and that these structures promote repeat expansions during DSB repair. Overexpression of Mre11p or Rad50p suppresses the inhibition of DSB repair by CAG(98) and significantly increases the average size of expansions found at the recipient locus. Both effects are dependent on the integrity of the Mre11p-Rad50p-Xrs2p complex. The Mre11 complex thus appears to be directly involved in removing CAG or CTG hairpins that arise frequently during DNA synthesis accompanying gene conversion of these trinucleotide repeats.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.