# Integrative single molecule studies: DNA repair and technology development

> **NIH NIH R35** · UNIV OF NORTH CAROLINA CHAPEL HILL · 2024 · $475,563

## Abstract

Project Summary
The overall objective of this proposal is to use existing and develop new single-molecule techniques to gain
mechanistic insights into the critical processes occurring during DNA repair. DNA repair processes, which are
the guardian of the genome, involve multiple sequential enzymatic steps that require the coordinated assembly
and action of many proteins on DNA. The transient nature of these interactions presents significant challenges
to elucidating the molecular mechanisms of DNA repair using traditional biochemical methods. Single molecule
approaches are well suited to overcome these difficulties; however, they present their own challenges, requiring
innovative solutions. My laboratory focuses on elucidating the molecular mechanisms of DNA mismatch repair
(MMR) and on development of single-molecule tools that give us access to previously unattainable information.
MMR plays a major role in reducing genomic mutations, including correcting DNA replication errors,
modulating cellular responses to DNA damaging agents, and preventing recombination between diverged
sequences. Mutations that inactivate MMR proteins cause Lynch syndrome, the most common hereditary
cancer, as well as resistance to several DNA damaging agents used to treat cancer. Surprisingly, in trinucleotide
repeat (TNR) expansion, which causes some neurodegenerative diseases, MMR proteins cause mutations that
promote repeat expansion and disease. MutSa/MutSb initiates MMR by binding to a mismatch/insertion
deletion loop and undergoing ATP-dependent conformational changes that promote its interaction with one or
more MutLa proteins. Subsequently, PCNA and ATP activate MutLa to incise the daughter strand, and MutSa
activates EXO1 to processively excise the DNA containing the error, followed by resynthesis and ligation.
Similarly, in TRE, MutSb binds looped out DNA trinucleotide repeats and recruits MutLa and/or MutLg, but
instead of leading to repair, this process promotes expansions. Understanding the molecular mechanisms that
underlie these different processes is essential for developing effective treatments for the associated cancers and
neurodegenerative diseases. Single-molecule, structural, and biochemical studies, including several from our
laboratory, indicate that the conformational dynamics and assembly states of the proteins and protein-DNA
complexes are central to the regulation of MMR and TRN expansion. We will continue our mechanistic studies
of MMR and extend them to TNR expansion. We are taking an integrative approach in which we utilize an
array of single-molecule techniques, including AFM and single-molecule fluorescence, to examine MMR in
multiple organisms in vitro and in vivo, as well as initiating studies on TNR expansion. We will focus on
examining the temporal and spatial assembly of proteins on DNA during initiation of MMR and TNR
expansion. Finally, we will continue to develop single-molecule tools, such as DREEM that allows us to “see”
DNA ins...

## Key facts

- **NIH application ID:** 10890600
- **Project number:** 5R35GM127151-07
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **Principal Investigator:** DOROTHY A ERIE
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $475,563
- **Award type:** 5
- **Project period:** 2018-06-01 → 2028-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10890600

## Citation

> US National Institutes of Health, RePORTER application 10890600, Integrative single molecule studies: DNA repair and technology development (5R35GM127151-07). Retrieved via AI Analytics 2026-06-23 from https://api.ai-analytics.org/grant/nih/10890600. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*