Chromatin Dynamics in DNA Damage Response Mechanisms

Chromatin, the organised complex of DNA and histone proteins, undergoes rapid and regulated structural changes upon DNA damage to facilitate detection, signalling and repair. Following insult by endogenous or exogenous agents, specific histone residues are phosphorylated, ubiquitinated or acetylated to mark sites of damage and recruit effector proteins. Concomitantly, ATP-dependent remodelling machines transiently reposition or evict nucleosomes, creating windows of accessibility for repair factors. These dynamic transitions modulate the balance between non-homologous end-joining and homologous recombination, orchestrate transcriptional silencing near lesions and influence replication restart after stress. Dysregulation of these processes underlies genome instability and contributes to cancer development, while targeted modulation of chromatin regulators offers therapeutic promise. Collectively, chromatin dynamics represent a versatile regulatory layer that integrates lesion recognition, repair pathway choice and chromatin restoration to safeguard genome integrity.

Research from Nature Portfolio

Recent studies have uncovered a novel phosphorylation event at histone H3 serine-57, catalysed by the checkpoint kinase CHK1, that loosens DNA–histone contacts and modulates both non-homologous end-joining and homologous recombination. Altering the phosphorylation state of this residue influences the kinetics of recovery from replication stress, the recruitment of repair factors and sensitivity to DNA-damaging agents, highlighting a conserved role for H3S57 modification across eukaryotes. In parallel, foundational work on histone H2AX phosphorylation continues to inform our understanding of early damage signalling. Phosphorylated H2AX establishes large chromatin domains that serve as platforms for assembly of sensors and transducers, thereby amplifying the damage signal and coordinating downstream repair and checkpoint pathways.

Chromatin Dynamics in DNA Damage Response Mechanisms publication trend

The graph below shows the total number of articles in chromatin dynamics in dna damage response mechanisms across all publications each year (not limited to Nature Index journals).

Technical terms

Chromatin: The assembled complex of DNA, histone proteins and associated factors that packages the genome and regulates its accessibility.

Nucleosome: The fundamental repeating unit of chromatin, comprising ~147 base pairs of DNA wrapped around an octamer of histone proteins.

Double-strand break (DSB): A DNA lesion in which both strands of the double helix are severed, posing a critical threat to genome stability.

Homologous recombination (HR): An error-free repair pathway that uses a homologous DNA sequence as template to restore integrity at a DSB.

Non-homologous end-joining (NHEJ): A rapid repair mechanism that ligates DNA ends directly, with minimal requirement for sequence homology.

ATP-dependent chromatin remodelling complex: A multi-protein machine that uses ATP hydrolysis to reposition, eject or restructure nucleosomes.

Post-translational modification: A covalent chemical alteration of histone tails (e.g. phosphorylation, ubiquitination or acetylation) that regulates chromatin function.

R-loop: A three-stranded nucleic acid structure formed when nascent RNA hybridises with its DNA template, displacing one DNA strand.

References

1. Histone H3 serine-57 is a CHK1 substrate whose phosphorylation affects DNA repair. Nature Communications (2023).
2. Different SWI/SNF complexes coordinately promote R-loop- and RAD52-dependent transcription-coupled homologous recombination. Nucleic Acids Research (2023).
3. Comprehensive Mapping of Histone Modifications at DNA Double-Strand Breaks Deciphers Repair Pathway Chromatin Signatures. Molecular Cell (2018).
4. Histone H2AX Is Phosphorylated in an ATR-dependent Manner in Response to Replicational Stress*. Journal of Biological Chemistry (2001).
5. Requirement for PBAF in Transcriptional Repression and Repair at DNA Breaks in Actively Transcribed Regions of Chromatin. Molecular Cell (2014).
6. ATP-dependent chromatin remodeling in the DNA-damage response. Epigenetics & Chromatin (2012).