ARAN - Access to Research at NUI Galway

Rapid unwinding of triplet repeat hairpins by Srs2 helicase of Saccharomyces cerevisiae

ARAN - Access to Research at NUI Galway

Show simple item record

dc.contributor.author Lahue, Robert S. en
dc.date.accessioned 2009-12-14T09:57:02Z en
dc.date.available 2009-12-14T09:57:02Z en
dc.date.issued 2008 en
dc.identifier.citation Dhar A. & Lahue R. S. (2008) Rapid unwinding of triplet repeat hairpins by Srs2 helicase of Saccharomyces cerevisiae. "Nucleic Acids Research" 36(10) 3366¿3373. en
dc.identifier.uri http://hdl.handle.net/10379/516 en
dc.description.abstract Expansions of trinucleotide repeats cause at least 15 heritable human diseases. Single-stranded triplet repeat DNA in vitro forms stable hairpins in a sequence-dependent manner that correlates with expansion risk in vivo. Hairpins are therefore considered likely intermediates during the expansion process. Unwinding of a hairpin by a DNA helicase would help protect against expansions. Yeast Srs2, but not the RecQ homolog Sgs1, blocks expansions in vivo in a manner largely dependent on its helicase function. The current study tested the idea that Srs2 would be faster at unwinding DNA substrates with an extrahelical triplet repeat hairpin embedded in a duplex context. These substrates should mimic the relevant intermediate structure thought to occur in vivo. Srs2 was faster than Sgs1 at unwinding several substrates containing triplet repeat hairpins or another structured loop. In contrast, control substrates with an unstructured loop or a Watson¿Crick duplex were unwound equally well by both enzymes. Results with a fluorescently labeled, three-way junction showed that Srs2 unwinding proceeds unabated through extrahelical triplet repeats. In summary, Srs2 maintains its facile unwinding of triplet repeat hairpins embedded within duplex DNA, supporting the genetic evidence that Srs2 is a key helicase in Saccharomyces cerevisiae for preventing expansions en
dc.format application/pdf en
dc.language.iso en en
dc.subject.lcsh Saccharomyces cerevisiae en
dc.subject.lcsh DNA en
dc.title Rapid unwinding of triplet repeat hairpins by Srs2 helicase of Saccharomyces cerevisiae en
dc.type Article en
dc.local.publishedsource http://dx.doi.org/10.1093/nar/gkn225 en
dc.description.peer-reviewed peer-reviewed en

Files in this item

This item appears in the following Collection(s)

Show simple item record