DNA Damage-Induced Reactive Oxygen Species: A Genotoxic Stress Response Open Access

Rowe, Lori Ann (2009)

Permanent URL: https://etd.library.emory.edu/concern/etds/x059c7885?locale=en
Published

Abstract

DNA Damage-Induced Reactive Oxygen Species: A Genotoxic Stress Response
By Lori Ann Rowe

Cellular DNA is essential for life, providing the genetic information required for building
and maintaining the cell. There are many factors, both endogenous and exogenous to cells that
can contribute to DNA damage. Aerobic organisms face the challenge of both utilizing oxygen to
survive and appropriately handling the reactive nature of oxygen. Reactive oxygen species
(ROS) are known to be produced both through endogenous cellular mechanisms and as a result of
exposure to exogenous agents. Increased levels of intracellular ROS are associated with several
human pathologies including neurological disorders, cardiovascular disease, and cancer.
Elevated levels of ROS can cause DNA damage, which can contribute to these pathological
changes. The eukaryotic model system, Saccharomyces cerevisiae, was utilized to investigate
DNA damage-induced ROS in the genotoxic stress response due to the fact that the DNA repair
pathways are highly conserved between yeast and humans. We examined the intracellular levels
of ROS in DNA repair-proficient (WT), repair-deficient (lacking base excision repair (BER-),
nucleotide excision repair (NER-), or both (BER-/NER-)), and ROS scavenging mutant ( sod1,
sod2, cta1, and ctt) mutants following exposure to methyl methanesulfonate (MMS) and
ultraviolet light (UV-C) and found that there is a dose-dependent increase in intracellular ROS.
To examine ROS as a signaling molecule in the DNA damage response, we assessed the
activation of a known oxidative stress responder, Yap1. We observed that Yap1 is activated in
response to DNA damage primarily repaired through BER-dependent mechanisms, but not NER.
To further define the role of Yap1 as a DNA damage responder, mutation rates and chromosomal
rearrangements in yap1 strains were determined. There is an increase in genomic instability in
yap1 mutant cells. These results suggest that while there is an increase in intracellular ROS
levels regardless of the type of DNA damage induced or the genetic background of the cell, the
signaling event by ROS sub-species that occurs following DNA damage is specific to the nature
of DNA damage. These studies also reveal that Yap1 is likely to function as a DNA damage
responder.

Table of Contents

TABLE OF CONTENTS

Chapter I:
Introduction







1


References







17


Figures







24

Chapter II:
DNA Damage-induced Reactive Oxygen Species


40
(ROS) Stress Response in Saccharomyces cerevisiae
Free Radical Biology & Medicine, 2008
Abstract







41
Introduction







42

Experimental Procedures





45
Results







48
Discussion







55

References







61
Figures







67

Chapter III:
Levels of Reactive Oxygen Species in ROS Scavenger

82



Mutants ( sod1, sod2, cta1, and ctt1)


Abstract







83


Introduction







84



Experimental Procedures





87


Results







89


Discussion







94


References







100


Figures







105

About this thesis

Rights statement
  • Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.
School
Department
Subfield / Discipline
Degree
Submission
Language
  • English
Research field
Keyword
Committee Chair / Thesis Advisor
Committee Members
Last modified

Primary PDF

Supplemental Files