# Repair of Environmentally Induced Mitochondrial DNA Damage

> **NIH NIH R01** · UNIVERSITY OF SOUTH ALABAMA · 2020 · $423,500

## Abstract

Project Summary/ Abstract
 This proposal connects metabolic dysfunction to the regulation of repair following mitochondrial DNA
(mtDNA) damage caused by environmental toxicants. Environmental agents such as ionizing radiation,
chemicals found in cigarette smoke, herbicides, and heavy metals as well as normal cellular metabolic
processes, generate reactive oxygen species (ROS) in cells. ROS cause damage to cellular DNA, which if not
properly repaired, can trigger genome instability and the progression of metabolic diseases including
neurodegenerative disorders, aging, and cancer. MtDNA is more susceptible than its nuclear counterpart to
oxidative stress. The base excision repair (BER) pathway mends damaged bases in both nuclear and
mitochondrial compartments. Specialized enzymes called DNA glycosylases play a critical role in initializing
BER by excising damaged bases and mediating other aspects of the repair process via essential
protein:protein interactions.
 We will determine the role and regulation of two DNA glycosylases, NEIL1 and NEIL2, in the repair of
mtDNA. We hypothesize that the NEIL enzymes form unique and distinct complexes with mitochondrial
proteins that are responsible for mtDNA replication and transcription including mitochondrial single-stranded
DNA binding protein (mtSSB), transcription factor A (TFAM), polymerase γ (Polγ), and the twinkle helicase.
Our central hypothesis is that complex formation between the NEIL enzymes and mitochondrial proteins drives
repair ahead of the replication/ transcription forks and is regulated via (de)acetylation. To address this
hypothesis, we will examine the functional interactions between the NEIL enzymes and the named
mitochondrial proteins via structure-driven analyses. Experiments using protein painting, small angle-X-ray
scattering, and X-ray crystallography will be used to determine the structures of complexes formed between
NEIL1, mtSSB, Polγ, and Twinkle as well as between NEIL2, TFAM, and Polγ. Next, we will test the impact of
(de)acetylation on NEIL function. High levels of acetyl-coenzyme A in the mitochondrion drives chemical
acetylation of proteins and our preliminary data suggests that NEIL2 is modified in this manner. Deacetylation
of the NEIL proteins by the NAD+-dependent sirtuin enzymes regulates protein function and will be explored
here. Cellular metabolism, mitochondrial dysfunction, and environmental toxicants that cause an increase in
ROS levels adversely impact the bioavailability of key metabolites (NAD+) required for deacetylation; a pivotal
aspect of our research. Lastly, we will study the localization of the NEIL enzymes under conditions of
environmentally induced oxidative stress and their impact on mitochondrial respiration, membrane potential,
and morphology. This will shed light on essential nuclear-mitochondrial crosstalk that results from oxidative
stress.
 MtDNA repair is a budding field, with the NEIL enzymes placed at the forefront of the repair process by
o...

## Key facts

- **NIH application ID:** 9844069
- **Project number:** 5R01ES030084-02
- **Recipient organization:** UNIVERSITY OF SOUTH ALABAMA
- **Principal Investigator:** Aishwarya Prakash
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $423,500
- **Award type:** 5
- **Project period:** 2019-04-01 → 2024-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9844069

## Citation

> US National Institutes of Health, RePORTER application 9844069, Repair of Environmentally Induced Mitochondrial DNA Damage (5R01ES030084-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9844069. Licensed CC0.

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