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Singlet oxygen-induced DNA damage
Han-Chun DeFedericis1, Helen B Patrzyc, Michael J Rajecki
1Department of Cellular Stress Biology, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
Radiation Research
|April 4, 2006
Summary
Researchers detected a specific DNA lesion caused by singlet oxygen in cells. This finding advances our understanding of oxidative stress and DNA damage mechanisms.
Area of Science:
- Biochemistry
- Molecular Biology
- Genetics
Background:
- Reactive oxygen species (ROS) cause oxidative stress, damaging cells and organisms.
- Singlet oxygen is a key ROS that preferentially damages guanine in DNA.
- Previous studies have not directly detected singlet oxygen-induced DNA lesions in cellular DNA.
Purpose of the Study:
- To isolate and detect a specific singlet oxygen-induced DNA lesion in cellular DNA.
- To develop a method for quantifying this lesion in biological samples.
Main Methods:
- Exposure of synthetic oligomers and HeLa cells to UVA radiation and methylene blue to generate singlet oxygen.
- Enzymatic excision of the lesion as a modified dinucleoside monophosphate.
- Liquid chromatography-tandem mass spectrometry (LC-MS/MS) for detection and quantification.
- Synthesis of a labeled pentamer as an internal standard.
Main Results:
- The singlet oxygen-induced DNA lesion was successfully isolated from synthetic oligomers.
- The lesion was detected in double-stranded DNA and in HeLa cells exposed to singlet oxygen.
- LC-MS/MS enabled the detection of the lesion as modified dinucleoside monophosphates.
Conclusions:
- This study provides the first direct detection of a singlet oxygen-induced DNA lesion in cellular DNA.
- The developed LC-MS/MS method allows for accurate quantification of this lesion.
- Findings contribute to understanding the role of singlet oxygen in DNA damage and oxidative stress.