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

JOURNAL OF MOLECULAR BIOLOGY

卷:374

Article

Bianco, Piero R. ; Bradfield, Justin J. ; Castanza, Lauren R. ; Donnelly, Andrea N.

关键词: Rad54;    recombination;    single molecule;    DNA helicase;    chromatin;   

DOI  :  10.1016/j.jmb.2007.09.052

来源: Elsevier

【 摘 要 】

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. (c) 2007 Elsevier Ltd. All rights reserved.

【 授权许可】

Free