Tsou, Pei-Lan , Song, Wen , Ow, David .
OXS1, a conserved eukaryotic HMG-box protein that confers resistance to oxidative stress tolerance.
Exposure to certain heavy metal and oxidative stress has been associated with an increase risk of cancer in humans. The biological effects of these exposures are thought to result from induction of reactive oxygen species (ROS) and inhibition of DNA repair enzymes. Hence, genes that confer cellular defense against oxidative stress are of fundamental interest to plant and animal health. Here, we report that overexpression of a new gene, oxs1+, in Schizosaccharomyces pombe confers hypertolerance to cadmium and oxidizing chemicals, such as diamide, tert-butylhydroperoxide, and hydrogen peroxide. Unlike most genes oxs1 appears not to be primarily regulated through the expression level but through the localization of the protein. OXS1 is exported to the cytoplasm by Crm1, but accumulates in the nucleus during oxidative stress. Exit from the nucleus also appears to be required for enhanced stress tolerance. We also found OXS1 can bind DNA in vitro, suggesting a possible role with DNA during stress. OXS1-like coding sequences are found in a wide range of eukaryotic organisms with all these proteins having a leu rich NES and a HMG box at the C-terminal region. As with S. pombe OXS1, Arabidopsis OXS1 is also regulated by Crm1/XPO1-mediated nucleocytoplasmic shuttling. Transgenic Arabidopsis producing the S. pombe or the Arabidopsis protein (AtOXS1) are more tolerant whereas Arabidopsis Atoxs1 mutants are more sensitive to oxidative stress.
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1 - Grand Valley State University, Cell and Mol. Biology, 243 Padnos Hall, 1 Campus Dr., Allendale, MI, 49401, USA
2 - Bio-Rad Laboratories
3 - United States Department of Agriculture/ UC Berkeley, Plant Gene Expression Center
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM