Top3-Rmi1 dissolve Rad51-mediated D loops by a topoisomerase-based mechanism

Clare L Fasching; Petr Cejka; Stephen C Kowalczykowski; Wolf-Dietrich Heyer

doi:10.1016/j.molcel.2015.01.022

Top3-Rmi1 dissolve Rad51-mediated D loops by a topoisomerase-based mechanism

Mol Cell. 2015 Feb 19;57(4):595-606. doi: 10.1016/j.molcel.2015.01.022.

Authors

Clare L Fasching¹, Petr Cejka¹, Stephen C Kowalczykowski², Wolf-Dietrich Heyer³

Affiliations

¹ Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, CA 95616-8665, USA.
² Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, CA 95616-8665, USA; Department of Molecular & Cellular Biology, University of California, Davis, Davis, CA 95616-8665, USA.
³ Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, CA 95616-8665, USA; Department of Molecular & Cellular Biology, University of California, Davis, Davis, CA 95616-8665, USA. Electronic address: [email protected].

Abstract

The displacement loop (D loop) is a DNA strand invasion product formed during homologous recombination. Disruption of nascent D loops prevents recombination, and during synthesis-dependent strand annealing (SDSA), disruption of D loops extended by DNA polymerase ensures a non-crossover outcome. The proteins implicated in D loop disruption are DNA motor proteins/helicases that act by moving DNA junctions. Here we report that D loops can also be disrupted by DNA topoisomerase 3 (Top3), and this disruption depends on Top3's catalytic activity. Yeast Top3 specifically disrupts D loops mediated by yeast Rad51/Rad54; protein-free D loops or D loop mediated by bacterial RecA protein or human RAD51/RAD54 resist dissolution. Also, the human Topoisomerase IIIa-RMI1-RMI2 complex is capable of dissolving D loops. Consistent with genetic data, we suggest that the extreme growth defect and hyper-recombination phenotype of Top3-deficient yeast cells is partially a result of unprocessed D loops.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

DNA Helicases / genetics
DNA Helicases / metabolism
DNA Helicases / physiology
DNA Repair Enzymes / genetics
DNA Repair Enzymes / metabolism
DNA Repair Enzymes / physiology
DNA-Binding Proteins / genetics
DNA-Binding Proteins / metabolism
DNA-Binding Proteins / physiology*
Homologous Recombination / physiology*
Humans
Models, Genetic*
Rad51 Recombinase / metabolism
Rad51 Recombinase / physiology*
RecQ Helicases / genetics
RecQ Helicases / metabolism
RecQ Helicases / physiology*
Saccharomyces cerevisiae / genetics
Saccharomyces cerevisiae Proteins / genetics
Saccharomyces cerevisiae Proteins / metabolism
Saccharomyces cerevisiae Proteins / physiology*
Species Specificity

Substances

DNA-Binding Proteins
Rmi1 protein, S cerevisiae
Saccharomyces cerevisiae Proteins
TOP3 protein, S cerevisiae
RAD51 protein, S cerevisiae
Rad51 Recombinase
RAD54 protein, S cerevisiae
SGS1 protein, S cerevisiae
DNA Helicases
RecQ Helicases
DNA Repair Enzymes

Abstract

Publication types

MeSH terms

Substances

Grants and funding