NAT10-mediated β-hydroxybutyrylation Facilitates DNA Replication, Reduces Replication Stress and Genomic Instability

Accurate DNA replication is essential for genome integrity, with dysregulated replication dynamics, replication stress and genomic instability-hallmarks of cancer and aging. Here, we identify NAT10-mediated β-hydroxybutyrylation (Kbhb) of histones that safeguards replication fork progression, alleviates replication stress, and preserves genomic stability. DNA fiber analyses show β-hydroxybutyrate (BHB) treatment enhances replication efficiency while maintaining fork symmetry, effects abolished by NAT10 depletion or inhibition. BrdU/EdU labeling, FACS analyses reveal that NAT10-mediated Kbhb accelerates replication fork velocity and shortens S-phase duration. LC-MS/MS profiling shows no significant changes in origin firing following BHB treatment. Mechanistically, NAT10-mediated Kbhb modulates chromatin association, thereby modulating chromatin accessibility to establish a replication-permissive environment. This epigenetic remodeling mitigates replication stress markers and genomic instability. Conserved effects in transformed and primary cell models position NAT10 as a metabolic-epigenetic nexus linking nutrient signaling to replication fidelity. Our findings suggest targeting Kbhb signaling as a potential therapeutic strategy against replication stress-associated pathologies.