title: Homologous recombination is stimulated by a decrease in dUTPase in Arabidopsis.
abstract: Deoxyuridine triphosphatase (dUTPase) enzyme is an essential enzyme that protects DNA against uracil incorporation. No organism can tolerate the absence of this activity. In this article, we show that dUTPase function is conserved between E. coli (Escherichia coli), yeast (Saccharomyces cerevisiae) and Arabidopsis (Arabidopsis thaliana) and that it is essential in Arabidopsis as in both micro-organisms. Using a RNA interference strategy, plant lines were generated with a diminished dUTPase activity as compared to the wild-type. These plants are sensitive to 5-fluoro-uracil. As an indication of DNA damage, inactivation of dUTPase results in the induction of AtRAD51 and AtPARP2, which are involved in DNA repair. Nevertheless, RNAi/DUT1 constructs are compatible with a rad51 mutation. Using a TUNEL assay, DNA damage was observed in the RNAi/DUT1 plants. Finally, plants carrying a homologous recombination (HR) exclusive substrate transformed with the RNAi/DUT1 construct exhibit a seven times increase in homologous recombination events. Increased HR was only detected in the plants that were the most sensitive to 5-fluoro-uracils, thus establishing a link between uracil incorporation in the genomic DNA and HR. Our results show for the first time that genetic instability provoked by the presence of uracils in the DNA is poorly tolerated and that this base misincorporation globally stimulates HR in plants.
authors.affiliation: Institut de Biologie des Plantes, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8618, Université Paris-Sud 11, Orsay, France.
authors.forename: Emeline
authors.initials: E
authors.lastname: Dubois
authors.forename: Dolores
authors.initials: D
authors.lastname: Córdoba-Cañero
authors.forename: Sophie
authors.initials: S
authors.lastname: Massot
authors.forename: Nicolas
authors.initials: N
authors.lastname: Siaud
authors.forename: Bertrand
authors.initials: B
authors.lastname: Gakière
authors.forename: Séverine
authors.initials: S
authors.lastname: Domenichini
authors.forename: Florence
authors.initials: F
authors.lastname: Guérard
authors.forename: Teresa
authors.initials: T
authors.lastname: Roldan-Arjona
authors.forename: Marie-Pascale
authors.initials: MP
authors.lastname: Doutriaux
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D053938:DNA Fragmentation / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics*; D005816:Genetic Complementation Test; D018745:Genome, Plant / Q000235:genetics; D020287:In Situ Nick-End Labeling; D007700:Kinetics; D009154:Mutation / Q000235:genetics; D011755:Pyrophosphatases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference / Q000187:drug effects; D051135:Rad51 Recombinase / Q000235:genetics / Q000378:metabolism; D011995:Recombination, Genetic / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000235:genetics; D014498:Uracil / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D000431:Ethanol; D014498:Uracil; D051135:Rad51 Recombinase; D011755:Pyrophosphatases; C020020:dUTP pyrophosphatase