title: Arabidopsis thaliana RNase H2 deficiency counteracts the needs for the WEE1 checkpoint kinase but triggers genome instability.
abstract: The WEE1 kinase is an essential cell cycle checkpoint regulator in Arabidopsis thaliana plants experiencing replication defects. Whereas under non-stress conditions WEE1-deficient plants develop normally, they fail to adapt to replication inhibitory conditions, resulting in the accumulation of DNA damage and loss of cell division competence. We identified mutant alleles of the genes encoding subunits of the ribonuclease H2 (RNase H2) complex, known for its role in removing ribonucleotides from DNA-RNA duplexes, as suppressor mutants of WEE1 knockout plants. RNase H2 deficiency triggered an increase in homologous recombination (HR), correlated with the accumulation of γ-H2AX foci. However, as HR negatively impacts the growth of WEE1-deficient plants under replication stress, it cannot account for the rescue of the replication defects of the WEE1 knockout plants. Rather, the observed increase in ribonucleotide incorporation in DNA indicates that the substitution of deoxynucleotide with ribonucleotide abolishes the need for WEE1 under replication stress. Strikingly, increased ribonucleotide incorporation in DNA correlated with the occurrence of small base pair deletions, identifying the RNase H2 complex as an important suppressor of genome instability.
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium.
authors.forename: Pooneh
authors.initials: P
authors.lastname: Kalhorzadeh
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium.
authors.forename: Zhubing
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium.
authors.forename: Toon
authors.initials: T
authors.lastname: Cools
authors.affiliation: Génétique, Reproduction et Développement, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6293-Clermont Université-Institut National de la Santé et de la Recherche Médicale U1103, F-63177 Aubière, France.
authors.forename: Simon
authors.initials: S
authors.lastname: Amiard
authors.affiliation: Department for Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany.
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Willing
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium.
authors.forename: Nancy
authors.initials: N
authors.lastname: De Winne
authors.affiliation: Department of Medical Protein Research, Flanders Institute for Biotechnology (VIB), B-9000 Ghent, Belgium Department of Biochemistry, Ghent University, B-9000 Ghent, Belgium.
authors.forename: Kris
authors.initials: K
authors.lastname: Gevaert
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium.
authors.forename: Geert
authors.initials: G
authors.lastname: De Jaeger
authors.affiliation: Department for Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany.
authors.forename: Korbinian
authors.initials: K
authors.lastname: Schneeberger
authors.affiliation: Génétique, Reproduction et Développement, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6293-Clermont Université-Institut National de la Santé et de la Recherche Médicale U1103, F-63177 Aubière, France.
authors.forename: Charles I
authors.initials: CI
authors.lastname: White
authors.affiliation: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium lieven.deveylder@psb.vib-ugent.be.
authors.forename: Lieven
authors.initials: L
authors.lastname: De Veylder
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020029:Base Pairing; D001483:Base Sequence; D020134:Catalytic Domain; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D017343:Genes, Plant; D042822:Genomic Instability / Q000187:drug effects; D006918:Hydroxyurea / Q000494:pharmacology; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D059645:Mutation Rate; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011995:Recombination, Genetic / Q000235:genetics; D016914:Ribonuclease H / Q000737:chemistry / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D012265:Ribonucleotides / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D012265:Ribonucleotides; D017346:Protein Serine-Threonine Kinases; C514674:WEE1 protein, Arabidopsis; C091139:ribonuclease HII; D016914:Ribonuclease H; D006918:Hydroxyurea