Mechanisms of chromatin signaling during DNA repair

The National Institute of General Medical Sciences awarded the University of Virginia $444,125 on September 1, 2026, under the Biomedical Research and Research Training program (CFDA 93.859) to investigate the molecular mechanisms of chromatin signaling during DNA repair.

The research examines how chromatin-modifying enzymes reorganize chromatin structure in response to DNA damage and restore that structure following repair, using histone ADP-ribosylation signaling during DNA excision repair as a model system. The work addresses two primary questions: how chromatin signaling cascades reorganize chromatin in response to damage, and how they restore chromatin structure after repair is complete. The research employs biochemistry, single-molecule fluorescence microscopy, and cryogenic electron microscopy to probe the dynamic interplay between chromatin structure, signaling cascades, and DNA repair mechanisms.

Performance occurs in Charlottesville, Virginia, with a period of performance from September 1, 2026, through May 31, 2031. The University of Virginia is the recipient. This is a Project Grant, the assistance type under which NIGMS funds investigator-initiated biomedical research of demonstrated scientific and technical merit.

Abstract

The chromatinized eukaryotic genome is constantly subjected to endogenous and exogenous assaults that result in the formation of DNA damage. This DNA damage must be effectively repaired to prevent mutagenesis, genomic instability, and multiple human diseases. Importantly, chromatin structure serves as a dynamic regulatory barrier that DNA repair proteins must overcome to successfully repair DNA damage and maintain genome integrity. However, overwhelming evidence indicates that chromatin structure inhibits the activity of DNA processing enzymes involved in DNA damage repair pathways. To overcome this chromatin barrier to repair, cells have acquired complex chromatin signaling cascades that are mediated by the sequential actions of multiple chromatin modifying enzymes. These chromatin modifying enzymes reorganize chromatin structure in response to DNA damage to facilitate DNA repair and restore chromatin structure back to the original state following DNA repair. While the chromatin modifying enzymes involved in these chromatin signaling cascades have been identified using various approaches, the molecular mechanisms that govern how chromatin signaling works during DNA repair remains poorly understood. The overall goal of this research program is to define the dynamic interplay between chromatin structure, chromatin signaling cascades, and DNA damage repair from a mechanistic perspective. In this proposal, we will use the histone ADP-ribosylation signaling cascade during DNA excision repair as a model system to probe two thematic questions at the interface of DNA repair and chromatin biology: (theme 1) how do chromatin signaling cascades reorganize chromatin structure in response to DNA damage?; and (theme 2) how do chromatin signaling cascades restore chromatin structure after DNA repair? Using a unique and innovative combination of biochemistry, single-molecule fluorescence microscopy, cryogenic electron microscopy, and molecular genetics approaches, we will address key knowledge gaps within these themes that will describe the molecular basis of histone ADP-ribosylation signaling during DNA excision repair. Ultimately, this work will establish fundamental principles of chromatin signaling during DNA repair that enhance our understanding of genome maintenance within chromatin. We envision this work will also aid in ongoing attempts to rationally target chromatin signaling cascades and DNA repair pathways in human disease.