Quantification of 8-oxoG in Plant Telomeres

Area of Science:

• Molecular Biology
• Genetics
• Plant Science

Background:

• Chemical modifications in DNA, such as oxidation, significantly influence gene regulation and chromatin structure.
• Oxidative damage to DNA is linked to genotoxicity, reduced genome integrity, and altered telomere dynamics.
• 8-oxoguanine (8-oxoG) is a common marker of oxidative DNA damage.

Purpose of the Study:

• To develop and apply a novel method for enriching telomeric DNA to study oxidative modifications in vivo.
• To quantify 8-oxoG levels in *Arabidopsis thaliana* telomeres under normal and oxidative stress conditions.
• To investigate the role of telomeres as hotspots for oxidative damage.

Main Methods:

• Development of a robust method for differential enrichment of telomeric DNA in solution.
• Application of downstream techniques to determine chemical modifications, specifically 8-oxoG.
• Measurement of 8-oxoG in *Arabidopsis thaliana* telomeres under varying oxidative stress levels.

Main Results:

• Telomere length remained unchanged in response to oxidative stress across different wild-type *Arabidopsis thaliana* accessions.
• Despite comprising a small fraction of the genome, telomeres contributed significantly (0.2-15%) to the total 8-oxoG.
• Plant telomeres exhibited approximately 100-fold higher 8-oxoG accumulation than the rest of the genome under standard conditions.
• Telomeres were identified as primary targets for further oxidative damage under stress.
• A potential inverse correlation was observed between 8-oxoG accumulation in the chromosome body and telomere length.

Conclusions:

• Telomeres in *Arabidopsis thaliana* are confirmed hotspots for 8-oxoguanine accumulation.
• Telomeres may function as sentinels of oxidative stress in plants, indicating a protective role.
• The findings highlight the vulnerability of telomeric DNA to oxidative damage and its implications for genome integrity.