Establishing a System to Evaluate the Effects of ROS-Induced DNA Damage on H-DNA

H-DNA, a three-stranded DNA conformation, has been found to be mutagenic in mammalian cells contributing to genetic instability and diseases such as cancer. Reactive oxygen species (ROS) which accumulates under oxidative stress is also a source of DNA damage and can lead to point mutations. We hypothesize that the H-DNA structure which includes a single-stranded region is more susceptible to DNA damage by ROS than the control B-DNA structure. The overall objective of this study is to examine the effects of oxidative stress on B-DNA and H-DNA-induced mutation frequency. A yeast system containing either an H-DNA-forming sequence or the control B-DNA sequence was used to compare mutation frequencies. As a first step, yeast cells were treated with hydrogen peroxide to induce oxidative stress and growth was measured over time to determine the concentration needed for the mutagenesis assay. We determined that a range of 0.2 mM to 2 mM H2O2 should be utilized for future experiments.