Chkuaseli, T. | bioRxiv Science

bioRxiv2026

A Distributed Architectural Code Governs DNA Repair

Repair of DNA double-strand breaks (DSBs) depends on large-scale changes in nuclear shape and genome organization. How damage signaling coordinates such remodeling remains unclear. We find that the human DNA damage response (DDR) couples interdependent, temporally ordered tubulin modifications to nuclear membrane and lipid regulation, driving nuclear reshaping (nucleomorphosis) through DSB-capturing nuclear envelope tubules (dsbNETs). Tubulin detyrosination by vasohibins 1/2 (VASH1/2) and acetylation by -tubulin acetyltransferase 1 (ATAT1) promote dsbNET formation and support both homologous recombination and non-homologous end joining. Microtubule-dependent processes also promote the phosphorylation-dependent inactivation of the membrane stress-sensing lipid regulator CTP cytidylyltransferase- (CCT), which typically restrains baseline nuclear lipid droplets (nLDs) and dsbNETs while supporting ATR signaling. Damage-induced nLD formation requires diacylglycerol acyltransferases 1/2 (DGAT1/2) and supports dsbNETs. Our findings reveal a distributed architectural code spanning interconnected cytoskeletal, membrane, and lipid regulators. This code governs nucleomorphosis and its role in DNA repair and genome stability.

molecular biology↗

bioRxiv2026

Dna2-intrinsic condensation regulates DNA end resection and reveals evolutionary redistribution of condensate grammar

Eukaryotic cells commonly use biomolecular condensation of DNA double-strand break (DSB) repair scaffolds and signaling assemblies to organize repair reactions in space and time. Yet whether DSB end-processing enzymes themselves encode tunable phase separation that potentiates resection remains unclear. Here we show that the long-range resection enzyme Dna2 forms liquid-like condensates through an intrinsically disordered region that is necessary and sufficient for phase separation and catalytic enhancement in Saccharomyces cerevisiae. Dna2 condensates concentrate DNA substrates and enhance end processing, whereas disrupting condensate formation impairs repair kinetics, checkpoint signaling, and chromosome stability. Grafting of the heterologous intrinsically disordered region of human FUS partly rescues condensate formation and function, and Cdk1-dependent phosphorylation sites tune condensate stability and enzymatic output in cis and in trans. Machine-learning-based analysis reveals that condensation-promoting features of fungal Dna2 are shared with a restricted set of human DNA2-associated resection regulators. Together, these findings define phosphorylation-tuned, enzyme-intrinsic phase separation as an organizational principle of DSB end resection while supporting a model in which condensation-promoting features are redistributed among factors operating within conserved genome maintenance pathways.

molecular biology↗