Abstract
Eukaryotic organisms evolved under aerobic conditions subjecting nuclear DNA to damage provoked by reactive oxygen species (ROS). Although ROS are thought to be a major cause of DNA damage, little is known about the molecular mechanisms protecting nuclear DNA from oxidative stress. Here we show that protection of nuclear DNA in plants requires a coordinated function of ROS-scavenging pathways residing in the cytosol and peroxisomes, demonstrating that nuclear ROS scavengers such as peroxiredoxin and glutathione are insufficient to safeguard DNA integrity. Both catalase (CAT2) and cytosolic ascorbate peroxidase (APX1) play a key role in protecting the plant genome against photorespiratory-dependent H(2)O(2)-induced DNA damage. In apx1/cat2 double-mutant plants, a DNA damage response is activated, suppressing growth via a WEE1 kinase-dependent cell-cycle checkpoint. This response is correlated with enhanced tolerance to oxidative stress, DNA stress-causing agents, and inhibited programmed cell death.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Arabidopsis / genetics*
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Arabidopsis / growth & development
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Arabidopsis / metabolism
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism
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Ascorbate Peroxidases
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Chromosomes, Plant / genetics
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Cluster Analysis
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Cytoplasm / metabolism
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DNA Damage*
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DNA, Plant / genetics*
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Gene Expression Profiling
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Gene Expression Regulation, Developmental
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Gene Expression Regulation, Plant
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Hydrogen Peroxide / pharmacology
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Immunoblotting
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Mutation
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Oligonucleotide Array Sequence Analysis
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Oxidants / pharmacology
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Oxidative Stress / drug effects
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Peroxidases / genetics
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Peroxidases / metabolism
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism
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Reactive Oxygen Species / metabolism*
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Reverse Transcriptase Polymerase Chain Reaction
Substances
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Arabidopsis Proteins
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Cell Cycle Proteins
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DNA, Plant
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Oxidants
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Reactive Oxygen Species
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Hydrogen Peroxide
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Peroxidases
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Ascorbate Peroxidases
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CAT2 protein, Arabidopsis
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Protein Serine-Threonine Kinases
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WEE1 protein, Arabidopsis