6th Annual Judith Ramaley Celebration of Research and Creative Scholarship
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Poster #54 Genotoxic Stress Results in Selective P-body Formation in S. cerevisiae Whitney Hopfauf*, Chris Bullard*, Blaine Rathmann, Tony Koch, Chad Sutter, Cara Michelson, Kristen Ackermann, Sara Segner Faculty Mentors: Ted Wilson and Scott P. Segal Survival mechanisms to cope with oxidative stress are conserved across all eukaryotes. However, our understanding of these mechanisms at the level of DNA and mRNA is poorly understood. Exposure to oxidizing agents can result in damage to lipids and nucleic acids, and can elicit a stress response. The genotoxic agent sodium dichromate oxidizes guanines resulting in formation of OxoG bases, or causes double strand breaks. In contrast, peroxides, allow for strong oxidation of lipids and nucleic acids. Control of translation may play a role as part of the DNA oxidative stress response. Upon exposing yeast to sodium dichromate, we saw a selective increase in P-bodies, with a treatment as low as 15 uM, whereas stress granules fail to form. P-bodies and stress granules are cytoplasmic structures in which non-translating mRNA are found. This suggests that stress granules contain stored RNA poised for translation. Whereas P-bodies contain RNA degradation factors, stress granules contain translation initiation factors. Moreover, the response occurs within 10 minutes of exposure, suggesting a model in which either damaged mRNA or mRNA transcribed from damaged genes is selectively degraded rather than stored. Currently, we are determining whether a co-treatment with anti-oxidants can abrogate this effect. This study provides novel insights into how yeast and perhaps other higher eukaryotic cells respond to DNA oxidation. |
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