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Updated: Aug 23, 2026

Visualizing and Quantifying Endonuclease-Based Site-Specific DNA Damage
Published on: August 21, 2021
DNA damage responses to oxidative stress
Ari Barzilai1, Ken-Ichi Yamamoto
1Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel. barzilia@post.tau.ac.il
Abstract:
The DNA damage response is a hierarchical process. DNA damage is detected by sensor proteins such as the MRN complex that transmit the information to transducer proteins such as ATM and ATR, which control the damage response through the phosphorylation of effector proteins. The extent of the DNA damage determines cell fate: cell cycle arrest and DNA repair or the activation of apoptotic pathways. In aerobic cells, reactive oxygen species (ROS) are generated as a by-product of normal mitochondrial activity. If not properly controlled, ROS can cause severe damage to cellular macromolecules, especially the DNA. We describe here some of the cellular responses to alterations in the cellular redox state during hypoxia or oxidative stress. Oxidative damage in DNA is repaired primarily via the base excision repair (BER) pathway which appears to be the simplest of the three excision repair pathways. To allow time for DNA repair, the cells activate their cell cycle checkpoints, leading to cell cycle arrest and preventing the replication of damage and defective DNA.
Insights
Cells activate DNA repair pathways, like base excision repair (BER), to fix oxidative damage caused by reactive oxygen species (ROS). Cell cycle checkpoints halt division, allowing time for DNA repair and preventing replication errors.
Area of Science:
- Molecular Biology
- Cellular Biology
- Biochemistry
Background:
- The DNA damage response (DDR) is a critical cellular process involving sensor, transducer, and effector proteins.
- Reactive oxygen species (ROS), by-products of mitochondrial activity, can cause significant DNA damage if not controlled.
- Cell fate, including cell cycle arrest, DNA repair, or apoptosis, is determined by the extent of DNA damage.
Purpose of the Study:
- To describe cellular responses to altered redox states during hypoxia and oxidative stress.
- To highlight the role of base excision repair (BER) in repairing oxidative DNA damage.
- To explain the activation of cell cycle checkpoints for DNA repair.
Main Methods:
- The study describes cellular responses and pathways involved in DNA damage and repair.
- Focuses on the base excision repair (BER) pathway for oxidative DNA damage.
- Explains the mechanism of cell cycle arrest via checkpoints.
Main Results:
- Cells activate specific DNA repair pathways in response to oxidative stress and hypoxia.
- The base excision repair (BER) pathway is a primary mechanism for repairing oxidative DNA damage.
- Cell cycle checkpoints are activated to arrest the cell cycle, facilitating DNA repair.
Conclusions:
- Cellular redox state alterations trigger coordinated DNA damage response mechanisms.
- Efficient DNA repair, particularly BER, is crucial for maintaining genomic integrity under oxidative stress.
- Cell cycle arrest is a vital component of the DNA damage response, ensuring proper repair before replication.
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