DNA Damage Response and Repair Mechanisms in Fanconi Anemia

Fanconi anemia (FA) is a hereditary disorder defined by chromosomal instability, progressive bone marrow failure and cancer susceptibility. At its core lies a specialised pathway dedicated to the detection and repair of DNA interstrand cross-links (ICLs), lesions that covalently tether the two strands of the double helix and obstruct replication and transcription. Eleven core complex proteins assemble at stalled replication forks, catalysing the monoubiquitination of FANCD2 and FANCI. This key activation step orchestrates recruitment of structure-specific endonucleases, translesion synthesis polymerases and homologous recombination factors to excise cross-links, restore fork integrity and complete repair. Helicases such as FANCJ and translocases like FANCM resolve DNA secondary structures and protect fragile sites, while crosstalk with BRCA proteins ensures accurate double-strand break repair. Failure at any stage elevates replication stress, triggers inflammatory signalling and drives stem cell attrition. Understanding the molecular choreography of FA proteins has yielded insights into targeted chemotherapy sensitisation, synthetic-lethality strategies and the preservation of genomic stability in both inherited disease and cancer.

Research from Nature Portfolio

Recent studies have revealed that the FANCJ helicase is essential for poly(ADP-ribose) polymerase 1 (PARP1) activity during S-phase replication. Loss of FANCJ diminishes PARP1 function by sequestering it at G-quadruplex DNA, thereby reducing sensitivity to PARP inhibitors and highlighting the critical interplay between helicase-mediated structure resolution and therapeutic response in BRCA-deficient settings.

Work on replisome composition has uncovered two distinct lesion-proximal complexes: one bound by DONSON in early S phase, predominantly in euchromatin, and another by FANCM in late S phase, associated with heterochromatin. This temporal and spatial segregation informs how FA proteins coordinate genome duplication under stress and may guide timing of inhibitor delivery.

Foundational research on common fragile sites has demonstrated that FANCM, together with FAAP24 and MHF1/2, suppresses double-strand breaks at AT-rich sequences via its translocase activity. Parallel studies show that Rad52 is indispensable for repairing these breaks, and combined loss of both factors produces synthetic lethality in tumour cells, suggesting a therapeutic opportunity for FANCM-deficient cancers.

DNA Damage Response and Repair Mechanisms in Fanconi Anemia publication trend

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

Technical terms

Interstrand cross-link (ICL): A covalent bond between complementary DNA strands that blocks replication and transcription.

Monoubiquitination: Attachment of a single ubiquitin molecule to a target protein, here activating FANCD2–FANCI for repair.

Replisome: The multiprotein complex that carries out DNA replication at the fork.

Homologous recombination: An error-free repair process using a sister chromatid as a template to mend double-strand breaks.

G-quadruplex: Four-stranded DNA secondary structure formed in guanine-rich regions that can impede replication.

References

1. Holding All the Cards—How Fanconi Anemia Proteins Deal with Replication Stress and Preserve Genomic Stability. Genes (2019).
2. FANCJ promotes PARP1 activity during DNA replication that is essential in BRCA1 deficient cells. Nature Communications (2024).
3. DONSON and FANCM associate with different replisomes distinguished by replication timing and chromatin domain. Nature Communications (2020).
4. The concerted roles of FANCM and Rad52 in the protection of common fragile sites. Nature Communications (2018).
5. FANCJ DNA helicase is recruited to the replisome by AND-1 to ensure genome stability. EMBO Reports (2024).
6. The FANC/BRCA Pathway Releases Replication Blockades by Eliminating DNA Interstrand Cross-Links. Genes (2020).