Dynamic Processing of Displacement Loops during Recombinational DNA Repair

Aurele Piazza (1, 2) , Shanaya Shital Shah (1) , William Douglass Wright (1) , Steven Gore (1) , Romain Koszul (2) , Wolf-Dietrich Heyer (1)

1 UC - University of California
2 Régulation spatiale des Génomes - Spatial Regulation of Genomes

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 activities controlling their metabolism. Nascent D-loops are detected within 2 h of DSB formation and extended in a delayed fashion in a genetic system designed to preclude downstream repair steps. The majority of nascent D-loops are disrupted 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 layer of quality control of HR relying on nascent D-loop dynamics.

Mots clés: topoisomerase; D-loop; Mph1; Rad54; Rdh54; Sgs1; Srs2; helicase; heteroduplex DNA; homologous recombination

Domaines: Sciences du Vivant [q-bio]; Génétique; Biochimie, Biologie Moléculaire; Biologie moléculaire

Aurele Piazza, Shanaya Shital Shah, William Douglass Wright, Steven Gore, Romain Koszul, et al.. Dynamic Processing of Displacement Loops during Recombinational DNA Repair. Molecular Cell, 2019, 73 (6), pp.1255-1266.e4. ⟨10.1016/j.molcel.2019.01.005⟩. ⟨pasteur-02868091⟩