Rad54 and Rdh54 occupy spatially and functionally distinct sites within the Rad51‐ssDNA presynaptic complex. (13th August 2020)

• Record Type: Journal Article
• Authors: Crickard, J Brooks; Kwon, Youngho; Sung, Patrick; Greene, Eric C
• Is Part Of: EMBO journal. Volume 39:Number 20(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-08-13
• Subjects: DNA repair -- homologous recombination -- Rad51 -- Rad54 -- Rdh54; Molecular biology -- Periodicals; 572.805
• DOI: 10.15252/embj.2020105705
• Languages: English
• ISSNs: 0261-4189

Abstract

Abstract: Rad54 and Rdh54 are closely related ATP‐dependent motor proteins that participate in homologous recombination (HR). During HR, these enzymes functionally interact with the Rad51 presynaptic complex (PSC). Despite their importance, we know little about how they are organized within the PSC, or how their organization affects PSC function. Here, we use single‐molecule optical microscopy and genetic analysis of chimeric protein constructs to evaluate the binding distributions of Rad54 and Rdh54 within the PSC. We find that Rad54 and Rdh54 have distinct binding sites within the PSC, which allow these proteins to act cooperatively as DNA sequences are aligned during homology search. Our data also reveal that Rad54 must bind to a specific location within the PSC, whereas Rdh54 retains its function in the repair of MMS‐induced DNA damage even when recruited to the incorrect location. These findings support a model in which the relative binding sites of Rad54 and Rdh54 help to define their functions during mitotic HR. Synopsis: Rad54 and Rdh54 are closely‐related ATPases that participate in homologous recombination. Single‐molecule studies suggest that Rdh54 can assist Rad54 as a supplementary motor, to help align homologous DNA sequences during the early stages of recombination. Rad54 and Rdh54 bind to unique non–overlapping sites within the Rad51–ssDNA presynaptic complex. Rad54 and Rdh54 binding site specificities are dictated by their N–terminal domains. Chimeric Rad54 and Rdh54 proteins with their N–terminal domains swapped can be redirected to incorrect sites. Rad54 only functions properly at its native location within the Rad51–ssDNA presynaptic complex. Rdh54 retains function regardless of where it is targeted. Abstract : Single‐molecule studies of two recombinase‐associated ATPases reveals that Rad54 acts at specific sites within the presynaptic complex, while closely‐related Rdh54 can function even at incorrect locations.