GO:1990391 DNA repair complex: Components, Assembly and Research Methods, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1990391 (DNA repair complex) is a cellular component term describing any protein complex dedicated to repairing DNA lesions, including base excision, nucleotide excision, double-strand break repair, and mismatch repair.
• The MRN complex (MRE11-RAD50-NBN) is a central DNA repair complex that senses and processes DNA double-strand breaks, and its dysfunction causes genomic instability.
• Homologous recombination requires coordinated assembly of multiple DNA repair complexes, such as the Rad55-Rad57 complex in yeast and the CHAMP1 complex in human cells.
• DNA repair complexes are regulated by post-translational modifications and accessory factors like WDFY2, which promotes MRN complex formation.
• Mutations in DNA repair complex components are linked to cancer predisposition, neurodegeneration, and developmental disorders.
• CRISPR-based knockout, knock-in, and point-mutation models are essential to dissect the assembly and function of DNA repair complexes in human cells.
Description
The Gene Ontology (GO) term GO:1990391, DNA repair complex, defines a cellular component comprising any protein complex that participates in DNA repair processes, including direct reversal, base excision repair, nucleotide excision repair, photoreactivation, bypass, double-strand break repair, and mismatch repair. This term captures the modular and dynamic nature of the molecular machines that safeguard genome integrity. Understanding these complexes is fundamental to molecular biology because their dysfunction leads to mutations, chromosomal rearrangements, and diseases such as cancer and neurodegeneration. The MRN complex (MRE11-RAD50-NBN) is a well-characterized DNA repair complex that acts as an early sensor of DNA double-strand breaks and is essential for homologous recombination and non-homologous end joining. Similarly, the Rad55-Rad57 complex in yeast and the CHAMP1 complex in humans illustrate the diversity of DNA repair complexes across species and pathways. Researchers study these complexes to uncover mechanisms of genome maintenance, to identify therapeutic targets, and to understand how mutations in complex components drive disease. The GO:1990391 term provides a standardized way to annotate and query these assemblies in genomic and proteomic datasets, facilitating comparative and functional analyses.
DNA repair complex At A Glance
| GO ID | GO:1990391 |
|---|---|
| GO term | DNA repair complex |
| Ontology | cellular_component |
| Synonym | DNA damage repair complex; WHY1 complex |
| Definition | A protein complex involved in DNA repair processes including direct reversal, base excision repair, nucleotide excision repair, photoreactivation, bypass, double-strand break repair pathway, and mismatch repair pathway. |
| Major function | DNA damage recognition, processing, and repair through multiple pathways |
| Examples | MRN complex (MRE11-RAD50-NBN), Rad55-Rad57 complex, CHAMP1 complex, WDFY2-associated MRN complex |
| Related processes | Homologous recombination, non-homologous end joining, base excision repair, nucleotide excision repair, mismatch repair |
What Is GO:1990391?
GO:1990391 (DNA repair complex) is a cellular component ontology term that describes a protein complex involved in DNA repair processes. According to QuickGO, it encompasses complexes that function in direct reversal, base excision repair, nucleotide excision repair, photoreactivation, bypass, double-strand break repair pathways, and mismatch repair. This definition emphasizes the functional unity of physically associated proteins that collectively recognize, process, and resolve DNA damage. The term includes well-known complexes such as the MRN complex, Rad55-Rad57, and CHAMP1 complex, which are essential for maintaining genomic stability.
Why Is DNA repair complex Important in Cell Biology?
DNA repair complexes are essential for maintaining genomic integrity and preventing mutations that can lead to cancer, neurodegeneration, and premature aging. The MRN complex, for instance, is a critical effector of DNA damage repair and its dysfunction is associated with genomic instability syndromes. Understanding how these complexes assemble, function, and are regulated provides insights into fundamental biology and offers targets for therapeutic intervention in diseases characterized by defective DNA repair.
• DNA repair complexes safeguard the genome against endogenous and exogenous DNA damage.
• Mutations in MRN complex components cause chromosomal instability and cancer predisposition.
• The Rad55-Rad57 complex is essential for homologous recombination and DNA repair in yeast.
• CHAMP1 complex directs heterochromatin assembly and promotes homology-directed DNA repair.
• WDFY2 promotes MRN complex formation required for homologous recombination-mediated DNA repair.
• Lamins, actin, myosin, spectrin, and the LINC complex contribute to DNA repair processes.
• Tuberous sclerosis complex proteins are linked to DNA repair regulation.
• MYST forms a NuA4-like complex that regulates DNA repair in Plasmodium falciparum.
• Dysfunctional DNA repair complexes are implicated in cancer, neurodegeneration, and developmental disorders.
• Targeting DNA repair complexes is a promising strategy in cancer therapy and precision medicine.
What Happens During DNA repair complex?
DNA Damage Recognition and Complex Assembly
In simple terms: The cell detects broken or damaged DNA and quickly assembles a repair crew at the site.
DNA repair complexes are recruited to sites of damage through sensor proteins that recognize specific lesions. The MRN complex (MRE11-RAD50-NBN) is one of the earliest sensors of DNA double-strand breaks, binding to DNA ends and initiating repair signaling. In homologous recombination, the Rad55-Rad57 complex facilitates the assembly of Rad51 filaments on single-stranded DNA, a critical step for strand invasion. The CHAMP1 complex is involved in directing heterochromatin assembly and promoting homology-directed DNA repair. WDFY2 promotes MRN complex formation, enhancing homologous recombination-mediated DNA repair. These examples illustrate the diversity of recognition and assembly mechanisms across different repair pathways.
DNA Processing and Lesion Removal
In simple terms: Once assembled, the repair complex cuts, trims, or removes the damaged DNA segment.
After recognition, DNA repair complexes process the damaged DNA. The MRN complex possesses nuclease activity that resects DNA ends to generate 3' single-stranded overhangs, a prerequisite for homologous recombination. In base excision repair, glycosylases and AP endonucleases remove damaged bases, while in nucleotide excision repair, multi-protein complexes excise bulky lesions. The Rad55-Rad57 complex stabilizes the Rad51 nucleoprotein filament during strand exchange. These processing steps are tightly regulated to ensure fidelity and prevent aberrant repair.
DNA Synthesis and Ligation
In simple terms: The missing DNA is filled in and sealed to restore the original sequence.
Following processing, DNA polymerases extend the 3' ends using the intact sister chromatid or homologous template, and ligases seal the nicks. The MRN complex coordinates with downstream factors to ensure efficient repair synthesis. In homologous recombination, Rad51-mediated strand invasion allows DNA synthesis across the break, a process supported by the Rad55-Rad57 complex. CHAMP1 complex promotes homology-directed repair, which involves accurate DNA synthesis. Defects in these steps lead to incomplete repair and genomic instability.
Chromatin Remodeling and Repair Site Accessibility
In simple terms: The repair machinery must access DNA wrapped around histones, so chromatin is loosened.
DNA repair complexes often require chromatin remodeling to access damaged sites. The CHAMP1 complex directs heterochromatin assembly, which can influence repair pathway choice. Lamins, actin, myosin, spectrin, and the LINC complex contribute to nuclear architecture and may facilitate DNA repair by maintaining nuclear integrity and organizing repair foci. MYST forms a NuA4-like complex in Plasmodium falciparum, acetylating histones to promote DNA repair. These examples highlight the interplay between chromatin structure and DNA repair complex function.
Cell Cycle Checkpoint and Repair Coordination
In simple terms: The cell pauses its cycle to allow time for repair, ensuring mistakes are fixed before division.
DNA repair complexes are integrated with cell cycle checkpoints. The MRN complex activates ATM kinase, which initiates checkpoint signaling and coordinates repair with cell cycle progression. The Rad55-Rad57 complex functions during homologous recombination, which is restricted to S/G2 phases. CHAMP1 complex promotes homology-directed repair, which is also cell-cycle regulated. Tuberous sclerosis complex proteins have been linked to DNA repair regulation, possibly through mTOR signaling. This coordination ensures that repair occurs before DNA replication or mitosis.
Key Genes Involved in GO:1990391 DNA repair complex
The following genes encode core components or regulators of DNA repair complexes annotated under GO:1990391.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MRE11 | Nuclease component of MRN complex; DNA end resection | Central to double-strand break repair; mutations cause ataxia-telangiectasia-like disorder |
| RAD50 | ATPase component of MRN complex; DNA binding and tethering | Essential for MRN function; mutations linked to Nijmegen breakage syndrome-like disorder |
| NBN (NBS1) | MRN complex subunit; ATM activation and checkpoint control | Mutations cause Nijmegen breakage syndrome; target for cancer therapy |
| RAD51 | RecA-like recombinase; strand invasion in homologous recombination | Key effector of homologous recombination; regulated by Rad55-Rad57 |
| RAD55 | Rad55-Rad57 complex; stabilizes Rad51 filament | Yeast model for homologous recombination; conserved in eukaryotes |
| RAD57 | Rad55-Rad57 complex; paralog of Rad51 | Facilitates Rad51-mediated strand exchange |
| CHAMP1 | CHAMP1 complex; directs heterochromatin assembly and HDR | Promotes homology-directed repair; implicated in neurodevelopmental disorders |
| WDFY2 | Promotes MRN complex formation | Required for homologous recombination-mediated DNA repair |
| LMNA | Lamin A/C; nuclear envelope protein | LINC complex and lamins contribute to DNA repair |
| ACTB | Actin; cytoskeletal protein | Actin and myosin facilitate DNA repair processes |
| MYH9 | Myosin heavy chain; cytoskeletal motor | Involved in DNA repair via nuclear architecture |
| SPTAN1 | Spectrin; cytoskeletal protein | Spectrin and LINC complex in DNA repair |
| TSC1 | Tuberous sclerosis complex 1; mTOR regulator | Linked to DNA repair regulation |
| TSC2 | Tuberous sclerosis complex 2; mTOR regulator | Linked to DNA repair regulation |
| MYST | Histone acetyltransferase; NuA4-like complex | Regulates DNA repair in Plasmodium falciparum |
| ATM | Kinase activated by MRN complex; checkpoint signaling | Master regulator of DNA damage response |
| BRCA1 | Homologous recombination factor; interacts with MRN | Breast cancer susceptibility; DNA repair complex component |
| BRCA2 | Homologous recombination factor; Rad51 loading | Breast cancer susceptibility; DNA repair complex component |
How Is DNA repair complex Regulated?
DNA repair complexes are regulated at multiple levels, including post-translational modifications, protein-protein interactions, and cell cycle-dependent expression. The MRN complex is activated by ATM-mediated phosphorylation and is subject to regulation by WDFY2, which promotes its formation. The Rad55-Rad57 complex is regulated by phosphorylation and its interaction with Rad51. CHAMP1 complex function is linked to heterochromatin assembly and may be regulated by chromatin modifiers. Tuberous sclerosis complex proteins, which regulate mTOR, have been implicated in DNA repair regulation, suggesting crosstalk between growth signaling and DNA repair. MYST-mediated acetylation regulates DNA repair in Plasmodium falciparum, indicating evolutionary conservation of regulatory mechanisms.
DNA repair complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| MRE11 | Ataxia-telangiectasia-like disorder; cancer predisposition | Knockout and point-mutation cell lines; mouse models |
| NBN | Nijmegen breakage syndrome; immunodeficiency | Knock-in of patient mutations; organoids |
| CHAMP1 | Neurodevelopmental disorder with intellectual disability | Knockout and knock-in iPSC-derived neurons |
| BRCA1/BRCA2 | Hereditary breast and ovarian cancer | Knockout cell lines; patient-derived xenografts |
| TSC1/TSC2 | Tuberous sclerosis complex; DNA repair defects | Knockout and overexpression models |
Cancer and Genomic Instability
Defects in DNA repair complexes lead to genomic instability and cancer predisposition. Mutations in MRN complex components (MRE11, RAD50, NBN) cause chromosomal instability syndromes with increased cancer risk. BRCA1 and BRCA2, which interact with DNA repair complexes, are well-known breast and ovarian cancer susceptibility genes. Targeting DNA repair complexes with inhibitors (e.g., PARP inhibitors) is a therapeutic strategy in cancers with homologous recombination defects.
Neurodegeneration and Developmental Disorders
DNA repair complex dysfunction is linked to neurodegenerative diseases and neurodevelopmental disorders. CHAMP1 complex mutations are associated with neurodevelopmental disorders characterized by intellectual disability. Defects in DNA repair complexes can lead to accumulation of DNA damage in neurons, contributing to neurodegeneration. The LINC complex and nuclear envelope proteins, such as lamins, are implicated in premature aging and muscular dystrophies with DNA repair defects.
Infectious Disease and Parasite Biology
DNA repair complexes in pathogens, such as the MYST NuA4-like complex in Plasmodium falciparum, are potential drug targets. Understanding how these complexes function in parasites can inform the development of new antimalarial therapies. The conservation of DNA repair mechanisms across species makes them attractive targets for antimicrobial development.
From DNA repair complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of MRN complex component impair homologous recombination? | MRE11 or NBN knockout cell lines |
| How do point mutations in RAD50 affect MRN assembly? | RAD50 point-mutation knock-in cells |
| Can CHAMP1 overexpression enhance homology-directed repair? | CHAMP1 overexpression cell lines |
| What is the role of WDFY2 in MRN complex formation? | WDFY2 knockout and tagged knock-in cells |
| How does Rad55-Rad57 complex stabilize Rad51 filaments? | Yeast Rad55 or Rad57 knockout strains |
| Does MYST acetylation regulate DNA repair in Plasmodium? | MYST knockout parasites and overexpression lines |
How to Study the DNA repair complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CRISPR knockout screens | Gene essentiality and drug sensitivity | Identify novel DNA repair complex genes |
| AP-MS | Protein-protein interactions | Map DNA repair complex interactome |
| Live-cell imaging | Foci formation and recruitment kinetics | Study DNA repair complex dynamics |
| In vitro reconstitution | Enzymatic activities (nuclease, strand exchange) | Mechanistic studies of MRN and Rad55-Rad57 |
| Cryo-EM | 3D structure of complexes | Structural analysis of DNA repair complexes |
| RNA-seq | Transcriptional changes upon DNA damage | Identify repair pathway activation |
| ChIP-seq | Chromatin binding of repair proteins | Map repair complex localization |
| Comet assay | DNA strand breaks | Assess repair capacity in knockout cells |
CRISPR-Based Genetic Screens
Genome-wide CRISPR knockout screens can identify genes whose loss sensitizes cells to DNA-damaging agents, revealing novel DNA repair complex components. These screens use libraries targeting all genes and select for resistance or sensitivity to drugs like PARP inhibitors or ionizing radiation.
Proteomics and Interactomics
Affinity purification coupled with mass spectrometry (AP-MS) can identify protein-protein interactions within DNA repair complexes. For example, WDFY2 was identified as a MRN complex interactor using proteomic approaches. Proximity labeling (BioID) can map dynamic interactions at DNA damage sites.
Imaging and Live-Cell Microscopy
Fluorescence microscopy of GFP-tagged repair proteins (e.g., MRE11, RAD51) allows visualization of DNA repair foci formation and resolution in real time. Live-cell imaging can track the recruitment kinetics of DNA repair complexes to laser-induced damage.
Biochemical Reconstitution and Structural Biology
Purified DNA repair complexes can be reconstituted in vitro to study their enzymatic activities, such as nuclease, helicase, or strand exchange. Cryo-EM and X-ray crystallography provide structural insights into complex assembly and DNA binding.
How CRISPR Can Be Used to Study GO:1990391 DNA repair complex
Knockout
CRISPR knockout of DNA repair complex genes (e.g., MRE11, NBN, CHAMP1) is used to assess their essentiality for DNA repair and cell survival. Knockout cell lines can be challenged with DNA-damaging agents to measure sensitivity and repair deficiency.
Point Mutation
Point mutations in DNA repair genes (e.g., RAD50, MRE11) can be introduced via CRISPR to model patient-derived mutations and study their impact on complex assembly and function.
Knock-in
Knock-in of tagged versions (e.g., GFP, HA) of DNA repair proteins allows for live-cell imaging and affinity purification of complexes. Knock-in of disease-associated mutations can create isogenic models for functional studies.
Overexpression
Overexpression of DNA repair complex components (e.g., CHAMP1, WDFY2) can be achieved by CRISPR-mediated knock-in of a strong promoter or by lentiviral transduction. This is useful to study gain-of-function effects and enhance repair capacity.
How EDITGENE Supports DNA repair complex Research
Researchers studying DNA repair complex-related genes often need to determine whether a candidate gene is causally involved in DNA repair, how mutations affect complex assembly, and whether modulating its activity can alter disease phenotypes. EDITGENE provides comprehensive CRISPR-based services to create precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for DNA repair complex research.
Related Products
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| ATM Knockout HEK293T Cell Line | EDJ-KQ211 | Human | 472 | Details Get a Quote |
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Frequently Asked Questions About DNA repair complex
What is GO:1990391 DNA repair complex?
GO:1990391 is a Gene Ontology cellular component term describing a protein complex involved in DNA repair processes such as base excision repair, nucleotide excision repair, and double-strand break repair.
What genes are involved in DNA repair complex?
Key genes include MRE11, RAD50, NBN, RAD51, RAD55, RAD57, CHAMP1, WDFY2, and BRCA1/2, among others.
What is the function of the MRN complex?
The MRN complex (MRE11-RAD50-NBN) senses DNA double-strand breaks, resects DNA ends, and activates ATM signaling for repair.
How is the DNA repair complex regulated?
It is regulated by post-translational modifications, protein interactions, and cell cycle checkpoints, with factors like WDFY2 promoting MRN assembly.
What diseases are associated with DNA repair complex mutations?
Mutations cause cancer predisposition, neurodegeneration, and developmental disorders such as Nijmegen breakage syndrome.
What methods are used to study DNA repair complexes?
CRISPR screens, AP-MS, live-cell imaging, and in vitro reconstitution are common methods.
What is the role of CHAMP1 complex in DNA repair?
CHAMP1 complex directs heterochromatin assembly and promotes homology-directed DNA repair.
How does WDFY2 regulate DNA repair?
WDFY2 promotes MRN complex formation, which is required for homologous recombination-mediated DNA repair.
What is the Rad55-Rad57 complex?
It is a yeast complex that stabilizes Rad51 filaments during homologous recombination.
Can CRISPR be used to study DNA repair complexes?
Yes, CRISPR knockout, knock-in, and point-mutation models are widely used to dissect DNA repair complex function.
Conclusion
GO:1990391 (DNA repair complex) represents a diverse and essential set of molecular machines that maintain genome integrity. From the MRN complex to Rad55-Rad57 and CHAMP1, these complexes are central to DNA repair pathways and are implicated in cancer, neurodegeneration, and infectious diseases. Continued research using CRISPR-based models and advanced proteomics will uncover new components and regulatory mechanisms, offering opportunities for therapeutic intervention.
References
- 1. Qiu S et al.. 2021. MRN complex is an essential effector of DNA damage repair.. J Zhejiang Univ Sci B 22(1):31-37 PMID: 33448185
- 2. Roy U et al.. 2021. The Role of the Rad55-Rad57 Complex in DNA Repair.. Genes (Basel) 12(9) PMID: 34573372
- 3. Li F et al.. 2025. CHAMP1 complex directs heterochromatin assembly and promotes homology-directed DNA repair.. Nat Commun 16(1):1714 PMID: 39962076
- 4. Lu YF et al.. 2025. WDFY2 promotes MRN complex formation required for homologous recombination-mediated DNA repair.. Cell Rep 44(11):116520 PMID: 41196680
- 5. Lambert MW. 2019. The functional importance of lamins, actin, myosin, spectrin and the LINC complex in DNA repair.. Exp Biol Med (Maywood) 244(15):1382-1406 PMID: 31581813
- 6. Habib SL. 2010. Tuberous sclerosis complex and DNA repair.. Adv Exp Med Biol 685:84-94 PMID: 20687497
- 7. Kalamuddin M et al.. 2024. MYST regulates DNA repair and forms a NuA4-like complex in the malaria parasite Plasmodium falciparum.. mSphere 9(4):e0014024 PMID: 38564734
- 8. Zabolotnaya E et al.. 2020. Turning the Mre11/Rad50 DNA repair complex on its head: lessons from SMC protein hinges, dynamic coiled-coil movements and DNA loop-extrusion?. Biochem Soc Trans 48(6):2359-2376 PMID: 33300987
