# MOLECULAR MECHANISMS OF DNA DAMAGE SIGNALING AND REPAIR

> **NIH NIH R01** · WASHINGTON UNIVERSITY · 2020 · $312,624

## Abstract

PROJECT ABSTRACT
 The overall goal of this project is to uncover novel mechanisms of genome maintenance during
chromosomal replication. The progression of replication forks is frequently challenged by both environmental
agents and intra-cellular causes. As such, cells must protect the fork structure in the face of replication stress
in order to proliferate and to maintain genome stability. Defects in fork maintenance cause cancer, premature
aging and other diseases. Paradoxically, obstruction of DNA replication is also a commonly used strategy for
cancer treatment. Despite its critical importance in genome maintenance, tumorigenesis and cancer treatment,
the molecular mechanisms of fork protection and maintenance remain poorly understood. In our effort to
address this fundamental question, we have identified a novel calcium- and AMPK-dependent signaling
pathway that protects fork structure upon replication stress by restraining the activity of the Exo1 nuclease to
avoid deleterious processing of fork DNA. Disruption of this pathway causes fork degradation, chromosomal
instability and compromised cell viability. Building on this initial finding, we describe experiments in this
proposal to further decipher this new fork protection pathway by identifying key players and mechanisms that
mediate its activation. In Aim 1, we will begin to define the molecular nature of the signal at stressed replication
forks that directly induces the elevation of intracellular calcium essential for the activation of the overall
pathway. Aim 2 seeks to identify key intermediate factors that mediate the induction of intracellular calcium
upon replication stress by using a candidate gene approach and by carrying out an unbiased genome-wide
CRISPR screen. In Aim 3, we will elucidate the key biochemical events that lead to the activation of AMPK for
fork maintenance in the replication stress response. By identifying and characterizing the upstream signal,
players and molecular processes, these studies will provide critical mechanistic insights into the novel calcium-
and AMPK-dependent pathway in safeguarding the fork structure under stress. This project will not only
expand our understanding of the replication stress response, but also lay a conceptual foundation for
developing more effective cancer therapeutic strategies targeting DNA replication and AMPK.
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## Key facts

- **NIH application ID:** 9915933
- **Project number:** 5R01GM098535-08
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Zhongsheng You
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $312,624
- **Award type:** 5
- **Project period:** 2012-04-05 → 2022-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9915933

## Citation

> US National Institutes of Health, RePORTER application 9915933, MOLECULAR MECHANISMS OF DNA DAMAGE SIGNALING AND REPAIR (5R01GM098535-08). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9915933. Licensed CC0.

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