8-oxo-dg

Definition

8-oxo-dg, or 8-oxoguanine, is an oxidized derivative of the nucleoside guanosine, formed through oxidative damage to DNA. This modification is a key biomarker of oxidative stress and is linked to genomic instability as it can mispair during DNA replication, leading to mutations and potentially contributing to the development of various diseases, including cancer.

5 Must Know Facts For Your Next Test

1. 8-oxo-dg can lead to G-C to T-A transversions, which are a common type of mutation that can occur during DNA replication.
2. This nucleoside is not only a marker for oxidative DNA damage but also plays a role in signaling pathways related to inflammation and cancer progression.
3. The presence of 8-oxo-dg in DNA can be measured using various techniques, such as mass spectrometry and high-performance liquid chromatography.
4. Increased levels of 8-oxo-dg have been associated with aging, neurodegenerative diseases, and a higher risk of cancer due to the accumulation of mutations.
5. Cells have specific mechanisms, such as the OGG1 enzyme, which recognize and repair 8-oxo-dg to prevent its mutagenic effects.

Review Questions

• How does 8-oxo-dg contribute to genomic instability?
  • 8-oxo-dg contributes to genomic instability primarily by mispairing during DNA replication. When DNA polymerase encounters 8-oxo-dg, it may incorporate adenine instead of cytosine, resulting in G-C to T-A transversions. This mutagenic process can lead to an accumulation of mutations in the genome, increasing the likelihood of disease development, particularly cancers.
• Discuss the significance of oxidative stress in relation to the formation of 8-oxo-dg and its implications for genomic stability.
  • Oxidative stress is significant because it creates an environment where reactive oxygen species (ROS) can damage DNA, leading to the formation of 8-oxo-dg. As a marker of oxidative damage, the presence of 8-oxo-dg reflects the extent of genomic stress. This damage, if unrepaired or mismanaged by cellular repair mechanisms, can contribute to genomic instability and increased mutation rates, setting the stage for various diseases.
• Evaluate the role of DNA repair mechanisms in mitigating the effects of 8-oxo-dg on genomic stability and how this knowledge could influence therapeutic approaches.
  • DNA repair mechanisms play a crucial role in countering the mutagenic effects of 8-oxo-dg by recognizing and excising this damaged base through processes like base excision repair. Understanding these mechanisms can guide therapeutic strategies aimed at enhancing DNA repair pathways or targeting specific enzymes like OGG1 to reduce mutation rates associated with oxidative stress. This knowledge could lead to potential interventions for age-related diseases and cancers linked with elevated levels of 8-oxo-dg.

Related terms

Oxidative Stress: A condition characterized by excessive free radicals that overwhelm the body's antioxidant defenses, leading to cellular damage and contributing to aging and various diseases.

DNA Repair Mechanisms: Cellular processes that detect and correct damage to DNA, including base excision repair which specifically targets modified bases like 8-oxo-dg.

Genomic Instability: An increased tendency of the genome to acquire mutations, often resulting from defects in DNA repair mechanisms or high levels of DNA damage.