title: Arabidopsis thalianaMRE11 is essential for activation of cell cycle arrest, transcriptional regulation and DNA repair upon the induction of double-stranded DNA breaks.
abstract: Given the fundamental role of MRE11 in many aspects of DNA metabolism and signalling in eukaryotes, we analysed the impact of several MRE11 mutations on DNA damage response (DDR) and DNA repair in Arabidopsis thaliana. Three different atmre11 and an atatm-2 mutant lines, together with the wild type (WT), were compared using a new Arabidopsis genotoxic assay for in situ evaluation of genome integrity and DNA damage repair efficiency after double strand break (DSB) induction. The results showed that, despite the phenotypic differences and different lengths of the putative truncated AtMRE11 proteins, all three atmre11 and the atatm-2 mutant lines exhibited common hypersensitivity to bleomycin treatment, where they only slightly reduced mitotic activity, indicating a G2/M checkpoint abrogation. In contrast to the WT, which reduced the frequency of chromosomal aberrations throughout the recovery period after treatment, none of the three atmre11 and atatm-2 mutants recovered. Moreover, atmre11-3 mutants, similarly to atatm-2 mutants, failed to transcriptionally induce several DDR genes and had altered expression of the CYCB1;1::GUS protein. Nevertheless, numerous chromosomal fusions in the atmre11 mutants, observed after DNA damage induction, suggest intensive DNA repair activity. These results indicate that functional and full-length AtMRE11 is essential for activation of the cell cycle arrest, transcriptional regulation and DNA repair upon induction of DSB.
authors.affiliation: Department of Biology, Faculty of Science, University of Split, Split, Croatia.
authors.forename: I
authors.initials: I
authors.lastname: Šamanić
authors.affiliation: Department of Biology, Faculty of Science, University of Split, Split, Croatia.
authors.forename: R
authors.initials: R
authors.lastname: Cvitanić
authors.affiliation: Ruđer Bošković Institute, Zagreb, Croatia.
authors.forename: J
authors.initials: J
authors.lastname: Simunić
authors.affiliation: Department of Biology, Faculty of Science, University of Split, Split, Croatia.
authors.forename: J
authors.initials: J
authors.lastname: Puizina
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D059447:Cell Cycle Checkpoints; D002869:Chromosome Aberrations; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D004260:DNA Repair; D018744:DNA, Plant / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D018745:Genome, Plant / Q000235:genetics; D000076228:MRE11 Homologue Protein; D009154:Mutation
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D004268:DNA-Binding Proteins; C492900:Mre11 protein, Arabidopsis; D000076228:MRE11 Homologue Protein
keywords: CYCB1;1::GUS; DNA damage response; ataxia telangiectasia-mutated; atmre1 mutants; genome instability.