title: Atmnd1-delta1 is sensitive to gamma-irradiation and defective in meiotic DNA repair.
abstract: The efficient repair of double-strand breaks (DSBs) in genomic DNA is crucial for the survival of all organisms. Mnd1 is suggested to promote the strand invasion step during meiotic recombination. We used a forward genetics approach, through the search for mutants, to characterize the Arabidopsis homologue of Mnd1. Atmnd1 null mutants exhibit normal vegetative and flower development. In contrast, during prophase I, chromosomes become fragmented resulting in random distribution of the fragments between polyads. Male and female meiosis are defective and strong accumulation of AtRAD51 was observed in atmnd1-delta1 nuclei. These results suggest that similarly to its yeast and animal homologues, AtMnd1 plays a role in DSB repair during meiosis. In addition, like its human homologue AtMnd1 is expressed in somatic cells. AtMnd1 expression is strongly induced by gamma-rays and null mutants show increased sensibility to gamma-rays. Taken together, these results suggest that AtMnd1 is also required for DSB repair in somatic cells.
authors.affiliation: UMR 8618, Institut de Biotechnologie des plantes, bât. 630, Université Paris-Sud, 91405 Orsay, France. domenich@ibp.u-psud.fr
authors.forename: Séverine
authors.initials: S
authors.lastname: Domenichini
authors.forename: Cécile
authors.initials: C
authors.lastname: Raynaud
authors.forename: Di-An
authors.initials: DA
authors.lastname: Ni
authors.forename: Yves
authors.initials: Y
authors.lastname: Henry
authors.forename: Catherine
authors.initials: C
authors.lastname: Bergounioux
mesh_terms: D017360:Arabidopsis / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D004260:DNA Repair; D004269:DNA, Bacterial / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D005091:Exons / Q000235:genetics; D035264:Flowers / Q000166:cytology; D005720:Gamma Rays; D018506:Gene Expression Regulation, Plant; D007438:Introns / Q000235:genetics; D008540:Meiosis; D016254:Mutagenesis, Insertional / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D051479:Plant Infertility; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051135:Rad51 Recombinase / Q000378:metabolism; D011836:Radiation Tolerance; D017422:Sequence Analysis, DNA
chemical_list: D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D018744:DNA, Plant; D012333:RNA, Messenger; C036483:T-DNA; C495146:ATRAD51 protein, Arabidopsis; D051135:Rad51 Recombinase