The Involvement of Arabidopsis Glutathione Peroxidase 8 in the Suppression of Oxidative Damage in the Nucleus and Cytosol

Plant Cell Physiol. 2012 Sep;53(9):1596-606. doi: 10.1093/pcp/pcs100. Epub 2012 Jul 5.

Abstract

A family of eight genes with homology to mammalian glutathione peroxidase (GPX) isoenzymes, designated AtGPX1-AtGPX8, has been identified in Arabidopsis thaliana. In this study we demonstrated the functional analysis of Arabidopsis AtGPX8 with peroxidase activity toward H(2)O(2) and lipid hydroperoxides using thioredoxin as an electron donor. The transcript and protein levels of AtGPX8 in Arabidopsis were up-regulated coordinately in response to oxidative damage caused by high-light (HL) stress or treatment with paraquat (PQ). Furthermore, the knockout Arabidopsis mutants of AtGPX8 (KO-gpx8) exhibited increased sensitivity to oxidative damage caused by PQ treatment in root elongation compared with the wild-type plants. In contrast, transgenic lines overexpressing AtGPX8 (Ox-AtGPX8) were less sensitive to oxidative damage than the wild-type plants. The levels of oxidized proteins in the KO-gpx8 and Ox-AtGPX8 lines were enhanced and suppressed, respectively, compared with the wild-type plants under HL stress or PQ treatment. The fusion protein of AtGPX8 tagged with green fluorescent protein was localized in the cytosol and nucleus of onion epidermal cells. In addition, the AtGPX8 protein was detected in the cytosolic and nuclear fractions prepared from leaves of Arabidopsis plants using the AtGPX8 antibody. Oxidative DNA damage under treatment with PQ increased in the wild-type and KO-gpx8 plants, while it decreased in the OX-AtGPX8 plants. These results suggest that AtGPX8 plays an important role in the protection of cellular components including nuclear DNA against oxidative stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 8-Hydroxy-2'-Deoxyguanosine
  • Arabidopsis / drug effects
  • Arabidopsis / enzymology*
  • Arabidopsis / genetics
  • Arabidopsis / radiation effects
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Blotting, Western
  • Cell Nucleus / enzymology
  • Cytosol / drug effects
  • Cytosol / enzymology*
  • Cytosol / radiation effects
  • DNA Damage
  • Deoxyguanosine / analogs & derivatives
  • Deoxyguanosine / metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Gene Expression Regulation, Enzymologic / drug effects
  • Gene Expression Regulation, Enzymologic / radiation effects
  • Gene Expression Regulation, Plant / drug effects
  • Gene Expression Regulation, Plant / radiation effects
  • Genes, Plant / genetics
  • Glutathione Peroxidase / genetics
  • Glutathione Peroxidase / metabolism*
  • Green Fluorescent Proteins / metabolism
  • Light
  • Oxidation-Reduction / drug effects
  • Oxidation-Reduction / radiation effects
  • Oxidative Stress* / drug effects
  • Oxidative Stress* / radiation effects
  • Paraquat / toxicity
  • Recombinant Proteins / metabolism
  • Stress, Physiological / drug effects
  • Stress, Physiological / genetics
  • Stress, Physiological / radiation effects
  • Subcellular Fractions / drug effects
  • Subcellular Fractions / metabolism
  • Subcellular Fractions / radiation effects
  • Substrate Specificity / drug effects
  • Substrate Specificity / radiation effects

Substances

  • Arabidopsis Proteins
  • Recombinant Proteins
  • Green Fluorescent Proteins
  • 8-Hydroxy-2'-Deoxyguanosine
  • GPX8 protein, Arabidopsis
  • Glutathione Peroxidase
  • Deoxyguanosine
  • Paraquat