title: BRCA2 is a mediator of RAD51- and DMC1-facilitated homologous recombination in Arabidopsis thaliana.
abstract: • Mutations in the breast cancer susceptibility gene 2 (BRCA2) are correlated with hereditary breast cancer in humans. Studies have revealed that mammalian BRCA2 plays crucial roles in DNA repair. Therefore, we wished to define the role of the BRCA2 homologs in Arabidopsis in detail. • As Arabidopsis contains two functional BRCA2 homologs, an Atbrca2 double mutant was generated and analyzed with respect to hypersensitivity to genotoxic agents and recombination frequencies. Cytological studies addressing male and female meiosis were also conducted, and immunolocalization was performed in male meiotic prophase I. • The Atbrca2 double mutant showed hypersensitivity to the cross-linking agent mitomycin C and displayed a dramatic reduction in somatic homologous recombination frequency, especially after double-strand break induction. The loss of AtBRCA2 also led to severe defects in male meiosis and development of the female gametophyte and impeded proper localization of the synaptonemal complex protein AtZYP1 and the recombinases AtRAD51 and AtDMC1. • The results demonstrate that AtBRCA2 is important for both somatic and meiotic homologous recombination. We further show that AtBRCA2 is required for proper meiotic synapsis and mediates the recruitment of AtRAD51 and AtDMC1. Our results suggest that BRCA2 controls single-strand invasion steps during homologous recombination in plants.
authors.affiliation: Botanical Institute II, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Seeliger
authors.forename: Stefanie
authors.initials: S
authors.lastname: Dukowic-Schulze
authors.forename: Rebecca
authors.initials: R
authors.lastname: Wurz-Wildersinn
authors.forename: Michael
authors.initials: M
authors.lastname: Pacher
authors.forename: Holger
authors.initials: H
authors.lastname: Puchta
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000196:embryology / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D024682:BRCA2 Protein / Q000378:metabolism*; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000378:metabolism*; D020090:Chromosome Segregation / Q000187:drug effects / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics; D059765:Homologous Recombination / Q000187:drug effects / Q000235:genetics*; D008540:Meiosis / Q000187:drug effects; D016685:Mitomycin / Q000494:pharmacology; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000187:drug effects / Q000235:genetics; D009154:Mutation / Q000235:genetics; D059645:Mutation Rate; D056771:Ovule / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D051479:Plant Infertility / Q000187:drug effects / Q000235:genetics; D011058:Pollen / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051135:Rad51 Recombinase / Q000378:metabolism*; D011938:Rec A Recombinases / Q000378:metabolism*; D012639:Seeds / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D024682:BRCA2 Protein; D018797:Cell Cycle Proteins; D004269:DNA, Bacterial; C036483:T-DNA; D016685:Mitomycin; C513034:ATDMC1 protein, Arabidopsis; C495146:ATRAD51 protein, Arabidopsis; D051135:Rad51 Recombinase; D011938:Rec A Recombinases