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bioRxiv · 10.1101/421990

Dynamic Processing of Displacement Loops During Recombinational DNA Repair

Piazza, A.·Shah, S. S.·Wright, W. D.·Gore, S. K.·Koszul, R.·Heyer, W.-D.
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Abstract

Displacement-loops (D-loops) are pivotal intermediates of homologous recombination (HR), a universal DNA double strand break (DSB) repair pathway. We developed a versatile assay for the physical detection of D-loops in vivo, which enabled studying the kinetics of their formation and defining the network of D-loop formation and reversal pathways. Nascent D-loops are detected within 2 hrs of DSB formation and extended over the next 2 hrs in a system allowing break-induced replication. The majority of D-loops are disrupted in wild type cells by two pathways: one supported by the Srs2 helicase and the other by the Mph1 helicase and the Sgs1-Top3-Rmi1 helicase-topoisomerase complex. Both pathways operate without significant overlap and are delineated by the Rad54 paralog Rdh54 in an ATPase-independent fashion. This study uncovers a novel layer of HR control in cells relying on nascent D-loop dynamics, revealing unsuspected complexities, and identifying a surprising role for a conserved Rad54 paralog.

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Piazza, A., Shah, S. S., Wright, W. D., Gore, S. K., Koszul, R., Heyer, W.-D.. 2018-09-20. Dynamic Processing of Displacement Loops During Recombinational DNA Repair. https://doi.org/10.1101/421990

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