title: The Arabidopsis SWR1 chromatin-remodeling complex is important for DNA repair, somatic recombination, and meiosis.
abstract: All processes requiring interaction with DNA are attuned to occur within the context of the complex chromatin structure. As it does for programmed transcription and replication, this also holds true for unscheduled events, such as repair of DNA damage. Lesions such as double-strand breaks occur randomly; their repair requires that enzyme complexes access DNA at potentially any genomic site. This is achieved by chromatin remodeling factors that can locally slide, evict, or change nucleosomes. Here, we show that the Swi2/Snf2-related (SWR1 complex), known to deposit histone H2A.Z, is also important for DNA repair in Arabidopsis thaliana. Mutations in genes for Arabidopsis SWR1 complex subunits photoperiod-independent Early Flowering1, actin-related protein6, and SWR1 complex6 cause hypersensitivity to various DNA damaging agents. Even without additional genotoxic stress, these mutants show symptoms of DNA damage accumulation. The reduced DNA repair capacity is connected with impaired somatic homologous recombination, in contrast with the hyper-recombinogenic phenotype of yeast SWR1 mutants. This suggests functional diversification between lower and higher eukaryotes. Finally, reduced fertility and irregular gametogenesis in the Arabidopsis SWR1 mutants indicate an additional role for the chromatin-remodeling complex during meiosis. These results provide evidence for the importance of Arabidopsis SWR1 in somatic DNA repair and during meiosis.
authors.affiliation: Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Viena, Austria.
authors.forename: Marisa
authors.initials: M
authors.lastname: Rosa
authors.forename: Mona
authors.initials: M
authors.lastname: Von Harder
authors.forename: Riccardo Aiese
authors.initials: RA
authors.lastname: Cigliano
authors.forename: Peter
authors.initials: P
authors.lastname: Schlögelhofer
authors.forename: Ortrun
authors.initials: O
authors.lastname: Mittelsten Scheid
mesh_terms: D000970:Antineoplastic Agents / Q000633:toxicity; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics; D004249:DNA Damage; D004260:DNA Repair / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D005298:Fertility / Q000235:genetics; D056130:Gametogenesis, Plant / Q000235:genetics; D059765:Homologous Recombination / Q000235:genetics*; D006918:Hydroxyurea / Q000633:toxicity; D008540:Meiosis / Q000235:genetics*; D008840:Microfilament Proteins / Q000235:genetics; D016685:Mitomycin / Q000633:toxicity; D046912:Multiprotein Complexes / Q000235:genetics*; D016254:Mutagenesis, Insertional; D009154:Mutation / Q000187:drug effects / Q000528:radiation effects; D021122:Protein Subunits / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014466:Ultraviolet Rays
chemical_list: C507995:ARP6 protein, Arabidopsis; D000970:Antineoplastic Agents; D029681:Arabidopsis Proteins; D002868:Chromosomal Proteins, Non-Histone; D004269:DNA, Bacterial; D008840:Microfilament Proteins; D046912:Multiprotein Complexes; C478983:PIE1 protein, Arabidopsis; D021122:Protein Subunits; C529050:SWC6 protein, Arabidopsis; C036483:T-DNA; D014157:Transcription Factors; D016685:Mitomycin; D006918:Hydroxyurea