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Principal Investigator: Mark Hedglin
Organization: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
Fiscal Year: 2024
Award: $394,265
Funding agency: National Institute of General Medical Sciences
Project Summary/Abstract
The overarching goal of my research program is to understand how the human genome is faithfully
replicated when it is constantly damaged by covalent modifications that can alter its coding properties. A focus
is on translesion DNA synthesis (TLS), the predominant DNA damage tolerance (DDT) pathway utilized in
humans to replicate damaged DNA. TLS utilizes specialized DNA polymerases that can accommodate an
array of DNA damages, albeit with lowered fidelities, and promotes cell survival in the face of DNA damage by
allowing replication of a damaged genome to continue. However, tight regulation is critical as aberrant TLS can
selectively propagate cells with increased mutagenesis and chromosomal rearrangements, which can lead to
cancer. Furthermore, because TLS promotes cell survival after exposure to DNA damaging agents, aberrant
TLS can also afford cancer cells the ability to overcome common chemotherapies that aim to trigger cell death
by acutely damaging DNA. Hence, TLS is a promising candidate for targeted cancer co-therapy. Despite the
established links between human health and TLS, the progression and regulation of TLS is unclear and many
key gaps persist in our fundamental knowledge that cloud our understanding of the contribution of TLS to
genetic inheritance and carcinogenesis. For example, human DDT can occur by at least three pathways but
what is the interplay between TLS and other DDT pathways? My long-standing interests and vast expertise in
human DNA damage repair and replication and my established ability to utilize a multi-faceted approach
integrating molecular biology, biochemistry, and biophysics provide a unique opportunity to fill these gaps. This
proposal will address the progression and regulation of TLS by tackling two broad areas that are each a
cornerstone of our fundamental understanding of TLS and DDT in general; 1) Activation of TLS and; 2) The
interplay between DDT pathways. To do so, we design and apply unique, quantitative approaches that utilize
kinetic techniques and can be adapted to many biological scenarios.
The PCNA sliding clamp is an essential DNA replication factor and is monoubiquitinated at sites of DNA
damage by the Rad6(Rad18)2 complex. PCNA monoubiquitination is imperative for human TLS and activates
this critical pathway by recruiting TLS factors. Area 1 will investigate how the activity of the human
Rad6(Rad18)2 complex is regulated to efficiently monoubiquitinate PCNA at DNA damage sites, activating
TLS. Human DDT can occur by at least three pathways including TLS and all emanate from a common
intermediate. Area 2 will investigate the interplay between TLS and other DDT pathways and decipher
functional relationships between key events in each pathway. This proposal investigates TLS in broad contexts
that consider the complexities and dynamics of cellular environments and will significantly advance our
fundamental understanding of how the human genome is faithfully replicated in the face of DNA damage and
inspire new avenues of research in cancer etiology and treatment.
Terms: <Acute><Area><Biochemistry><Biological><Biological Chemistry><Biophysics><Cancer Cause><Cancer Etiology><Cancer Induction><Cancer Treatment><Cancers><Cell Body><Cell Death><Cell Survival><Cell Viability><Cells><Chromosomal Rearrangement><Clampings><Closure by clamp><Code><Coding System><Complex><Critical Paths><Critical Pathways><DNA Damage><DNA Damage Repair><DNA Injury><DNA Molecular Biology><DNA Polymerases><DNA Repair><DNA Replicating Damage><DNA Replication><DNA Replication Damage><DNA Replication Factor><DNA Synthesis><DNA Synthesis Factor><DNA biosynthesis><DNA-Dependent DNA Polymerases><DNA-Directed DNA Polymerase><Disease><Disorder><Dysfunction><Endothelial Cell Growth Factor><Environment><Event><Exposure to><FGF><Fibroblast Growth Factor><Fibroblast Growth Factor Gene Family><Fibroblast Growth Regulatory Factor><Functional disorder><Genetic><Genetics-Mutagenesis><Genome><Goals><Health><Human><Human Activities><Human Genome><Kinetics><Knowledge><Link><Malignant Cell><Malignant Neoplasm Therapy><Malignant Neoplasm Treatment><Malignant Neoplasms><Malignant Tumor><Modern Man><Modification><Molecular><Molecular Biology><Monoubiquitination><Mutagenesis><Mutagenesis Molecular Biology><Pathway interactions><Physiopathology><Property><Regulation><Research><Research Proposals><Site><Slide><Techniques><Unscheduled DNA Synthesis><anti-cancer therapy><biologic><biophysical foundation><biophysical principles><biophysical sciences><cancer cell><cancer therapy><cancer-directed therapy><carcinogenesis><chemotherapy><design><designing><human DNA damage><human whole genome><interest><malignancy><necrocytosis><neoplasm/cancer><pathophysiology><pathway><programs><recruit>