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Rad54 oligomers translocate and cross-bridge double-stranded DNA to stimulate synapsis.

ABSTRACT: Rad54 is a key component of the eukaryotic recombination machinery. Its presence in DNA strand-exchange reactions in vitro results in a significant stimulation of the overall reaction rate. Using untagged Rad54, we show that this stimulation can be attributed to enhancement of the formation of a key reaction intermediate known as DNA networks. Using a novel, single DNA molecule, dual-optical tweezers approach we show how Rad54 stimulates DNA network formation. We discovered that Rad54 oligomers possess a unique ability to cross-bridge or bind double-stranded DNA molecules positioned in close proximity. Further, Rad54 oligomers rapidly translocate double-stranded DNA while simultaneously inducing topological loops in the DNA at the locus of the oligomer. The combination of the cross-bridging and double-stranded DNA translocation activities of Rad54 stimulates the formation of DNA networks, leading to rapid and efficient DNA strand exchange by Rad51.

SUBMITTER: Bianco PR

PROVIDER: S-EPMC2128729 | biostudies-literature | 2007 Nov

REPOSITORIES: biostudies-literature

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Rad54 oligomers translocate and cross-bridge double-stranded DNA to stimulate synapsis.

Bianco Piero R PR Bradfield Justin J JJ Castanza Lauren R LR Donnelly Andrea N AN

Journal of molecular biology 20070922 3

Rad54 is a key component of the eukaryotic recombination machinery. Its presence in DNA strand-exchange reactions in vitro results in a significant stimulation of the overall reaction rate. Using untagged Rad54, we show that this stimulation can be attributed to enhancement of the formation of a key reaction intermediate known as DNA networks. Using a novel, single DNA molecule, dual-optical tweezers approach we show how Rad54 stimulates DNA network formation. We discovered that Rad54 oligomers ...[more]

PMID: 17949748

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