GO:0043240 Fanconi anaemia nuclear complex: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0043240 (Fanconi anaemia nuclear complex) is a multi-subunit protein complex that includes FANCA, FANCC, FANCE, FANCF, and FANCG, and is required for monoubiquitylation of FANCD2.
• The complex functions as an E3 ubiquitin ligase module that activates the downstream FANCI/FANCD2 complex, which is essential for protection against chromosome breakage and for homologous recombination.
• Loss of FA core complex function causes Fanconi anaemia, a genome instability disorder characterized by bone marrow failure, developmental defects, and cancer predisposition.
• The FA core complex promotes CtIP-dependent end resection at DNA double-strand breaks, linking it directly to homologous recombination.
• FA core subunits are transcriptionally regulated, and their repression (e.g., by TSN via JAK/STAT1 signaling) can disrupt pathway activation in cancers such as bladder cancer.
• Experimental models for studying GO:0043240 include CRISPR knockout, point mutation, knock-in, and overexpression cell lines, as well as functional assays for DNA repair and chromosome stability.
Description
The Fanconi anaemia nuclear complex (GO:0043240) is a multi-protein assembly composed of the FA core proteins, including FANCA, FANCC, FANCE, FANCF, and FANCG, that functions in the activation of FANCD2 by monoubiquitylation and is essential for protection against chromosome breakage. This complex is a central node in the Fanconi anaemia (FA) DNA repair pathway, which coordinates homologous recombination and replication fork protection. Researchers study GO:0043240 to understand how cells maintain genome stability, why its disruption leads to bone marrow failure and cancer predisposition, and how its activity can be targeted in cancer therapy. The complex is also emerging as a regulator of R-loop homeostasis and mRNA export through its downstream effectors. Given its role in DNA damage response and its links to chemoresistance, the FA core complex is a high-priority target for functional genomics and therapeutic development.
Fanconi anaemia nuclear complex At A Glance
| GO ID | GO:0043240 |
|---|---|
| GO term | Fanconi anaemia nuclear complex |
| Ontology | cellular_component |
| Synonym | FA complex, FA core complex, Fanconi anaemia complex, FA nuclear complex |
| Major function | Activates FANCD2 by monoubiquitylation; protects against chromosome breakage |
| Subunits | FANCA, FANCC, FANCE, FANCF, FANCG (and associated proteins) |
| Downstream target | FANCD2 (monoubiquitylation) |
| Associated disease | Fanconi anaemia, cancer predisposition |
| Research methods | CRISPR KO/point mutation/knock-in, DNA repair assays, proteomics |
What Is GO:0043240?
GO:0043240, the Fanconi anaemia nuclear complex, is a cellular component defined as a protein complex composed of the Fanconi anaemia proteins including A, C, E, G and F (FANCA-F). It functions in the activation of the downstream protein FANCD2 by monoubiquitylation and is essential for protection against chromosome breakage. The complex is also known as the FA complex, FA core complex, Fanconi anaemia complex, or FA nuclear complex.
Why Is Fanconi anaemia nuclear complex Important in Cell Biology?
The Fanconi anaemia nuclear complex is essential for genome maintenance, and its dysfunction leads to Fanconi anaemia, a disorder characterized by bone marrow failure, developmental abnormalities, and heightened cancer risk. Understanding GO:0043240 provides mechanistic insight into how cells repair DNA interstrand crosslinks and double-strand breaks, and how defects in this complex drive tumorigenesis and chemoresistance. Moreover, the complex is a potential therapeutic target because its loss creates specific vulnerabilities that can be exploited with DNA-damaging agents or targeted inhibitors.
• Mutations in FA core complex genes cause Fanconi anaemia, a rare inherited bone marrow failure syndrome.
• The complex is required for monoubiquitylation of FANCD2, a key step in the FA pathway.
• It promotes CtIP-dependent end resection, linking it to homologous recombination.
• Loss of FA core function leads to chromosome breakage and genomic instability.
• FA core subunits are transcriptionally repressed in some cancers, contributing to pathway inactivation.
• The complex interacts with R-loop regulation and mRNA export through FANCI/FANCD2.
• FA core components are involved in replication stress responses and can influence sensitivity to chemotherapy.
• Defective FA pathway is associated with microhomology-mediated end-joining in SMARCB1-deficient tumors.
• The complex is a target for CRISPR screening to identify synthetic lethal interactions.
• Studying GO:0043240 aids in understanding cancer predisposition and potential therapies.
Fanconi anaemia nuclear complex: Mechanism, Structure, and Regulation
Activation of the FA Core Complex
In simple terms: The FA core complex is switched on when DNA is damaged.
The Fanconi anaemia nuclear complex is activated in response to DNA damage, particularly interstrand crosslinks and double-strand breaks. Upon damage, the core complex including FANCA, FANCC, FANCE, FANCF, and FANCG assembles in the nucleus and catalyzes the monoubiquitylation of FANCD2. This activation is essential for the downstream DNA repair processes and for protection against chromosome breakage.
Monoubiquitylation of FANCD2
In simple terms: The complex attaches a small tag to FANCD2 to turn on the repair pathway.
The FA core complex functions as an E3 ubiquitin ligase that monoubiquitylates FANCD2, a critical step for its recruitment to chromatin and for the formation of the FANCI/FANCD2 complex. This modification is required for the DNA damage response and for maintaining genome stability.
Role in Homologous Recombination
In simple terms: The complex helps cells accurately repair broken DNA.
The FA core complex promotes CtIP-dependent end resection at DNA double-strand breaks, which is a prerequisite for homologous recombination. This function links the complex directly to the repair of double-strand breaks and to the maintenance of replication fork stability.
Structure and Composition
In simple terms: The complex is made of several proteins that work together.
The Fanconi anaemia nuclear complex is composed of multiple subunits, including FANCA, FANCB, FANCC, FANCE, FANCF, FANCG, and FANCL, along with associated proteins such as FAAP20 and FAAP100. The complex assembles in the nucleus and its integrity is required for its ubiquitin ligase activity.
Regulation of the FA Core Complex
In simple terms: The complex can be turned down by other signals in cancer.
The expression of FA core subunits can be transcriptionally repressed. For example, TSN disrupts FA pathway activation through JAK/STAT1-mediated transcriptional repression of FA core subunits in bladder cancer. Additionally, the complex is regulated by post-translational modifications and interactions with other DNA repair proteins.
Key Genes Involved in GO:0043240 Fanconi anaemia nuclear complex
The following genes encode components or regulators of the Fanconi anaemia nuclear complex (GO:0043240) and are commonly studied in the context of DNA repair and cancer.
| Gene | Major Role | Research Relevance |
|---|---|---|
| FANCA | Core complex subunit; required for FANCD2 monoubiquitylation | Most commonly mutated in Fanconi anaemia; target for KO studies |
| FANCC | Core complex subunit; involved in interstrand crosslink repair | Mutations cause FA; studied in hematopoietic failure |
| FANCE | Core complex subunit; interacts with FANCD2 | Essential for FA pathway activation |
| FANCF | Core complex subunit; stabilizes the complex | Mutations lead to FA; used in KO models |
| FANCG | Core complex subunit; involved in complex assembly | Defects cause FA; studied in DNA repair |
| FANCL | E3 ubiquitin ligase; monoubiquitylates FANCD2 | Catalytic subunit; target for point mutation studies |
| FANCD2 | Downstream target; monoubiquitylated by core complex | Key effector; knockout causes FA |
| FANCI | Forms complex with FANCD2; involved in R-loop regulation | Regulates mRNA export and DNA damage response |
| FANCB | Core complex subunit; X-linked | Mutations cause FA; studied in assembly |
| FAAP20 | Accessory protein; links complex to ubiquitin | Modulates complex stability |
| FAAP100 | Accessory protein; required for complex integrity | Supports FANCD2 monoubiquitylation |
| BRCA2 | Homologous recombination factor; interacts with FA pathway | Synthetic lethality with FA defects |
| RAD51 | Recombinase; downstream of FA pathway | Functional readout of HR |
| CtIP | End resection factor; promoted by FA core complex | Links FA to homologous recombination |
| RNF4 | Ubiquitin ligase; sustains replication | Interacts with FA pathway in cancer |
| SLFN11 | Replication stress response; RPA exhaustion | Potential biomarker in FA-deficient cells |
| SMARCB1 | Chromatin remodeler; MMEJ defects | Associated with FA pathway in tumors |
| TSN | Represses FA core subunits via JAK/STAT1 | Regulator of FA pathway in bladder cancer |
How Is Fanconi anaemia nuclear complex Regulated?
The Fanconi anaemia nuclear complex is regulated at multiple levels. Transcriptionally, FA core subunit genes can be repressed by signaling pathways such as JAK/STAT1, as shown for TSN in bladder cancer. Post-translationally, the complex is activated by DNA damage and its catalytic activity is directed toward FANCD2. Additionally, the complex interacts with other DNA repair factors like CtIP and RNF4, which modulate its function in homologous recombination and replication.
Fanconi anaemia nuclear complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| FANCA | Fanconi anaemia, bone marrow failure | CRISPR KO in hematopoietic stem cells |
| FANCC | Fanconi anaemia, leukemia predisposition | Point mutation knock-in in cell lines |
| FANCD2 | Fanconi anaemia, DNA repair defect | Knockout and rescue with tagged FANCD2 |
| FANCI | R-loop regulation, mRNA export defects | Overexpression and KO models |
| TSN | Bladder cancer, FA pathway repression | Overexpression and knockdown in cancer cells |
Fanconi Anaemia
Biallelic mutations in FA core complex genes (e.g., FANCA, FANCC, FANCE, FANCF, FANCG) cause Fanconi anaemia, an inherited disorder characterized by bone marrow failure, congenital anomalies, and increased cancer susceptibility. The disease results from defective DNA repair and chromosome instability due to loss of FANCD2 monoubiquitylation.
Cancer Predisposition and Tumorigenesis
Defects in the FA core complex are associated with various cancers, including acute myeloid leukemia and solid tumors. In bladder cancer, transcriptional repression of FA core subunits by TSN disrupts pathway activation, contributing to tumor progression. Additionally, the FA pathway is linked to replication stress and chemoresistance, making it a therapeutic target.
R-Loop Regulation and mRNA Export
The FANCI/FANCD2 complex, downstream of the FA core, links DNA damage response to R-loop regulation through SRSF1-mediated mRNA export. This connection suggests that FA core complex dysfunction may impact RNA metabolism and contribute to disease pathology beyond DNA repair.
From Fanconi anaemia nuclear complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of FANCA impair FANCD2 monoubiquitylation? | FANCA knockout cell line |
| Does a point mutation in FANCL abolish E3 ligase activity? | FANCL point-mutation knock-in |
| Can tagged FANCD2 rescue DNA repair? | Knock-in of tagged FANCD2 |
| Does overexpression of TSN repress FA core subunits? | TSN overexpression in bladder cancer cells |
| Is FANCI/FANCD2 involved in R-loop regulation? | FANCI/FANCD2 knockout and overexpression |
| Does RNF4 sustain replication in FA-deficient cells? | RNF4 knockout and overexpression |
How to Study the Fanconi anaemia nuclear complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Comet assay | DNA damage and repair | Assess FA pathway function |
| Chromosome breakage analysis | Chromosomal instability | Diagnosis of Fanconi anaemia |
| Immunoprecipitation/Western | Protein interactions and ubiquitylation | Detect FANCD2 monoubiquitylation |
| RNA-seq | Transcriptional changes | Identify FA gene repression |
| CRISPR screen | Gene essentiality and synthetic lethality | Find targets in FA-deficient cells |
| Mass spectrometry | Protein complex composition | Map FA core interactome |
| R-loop detection | RNA:DNA hybrids | Link FA pathway to R-loop regulation |
DNA Repair Assays
Functional assays such as comet assay, chromosome breakage analysis, and homologous recombination reporters are used to measure the integrity of the FA pathway. These assays can quantify sensitivity to interstrand crosslinking agents like mitomycin C.
Proteomics and Immunoprecipitation
Affinity purification coupled with mass spectrometry can identify interacting partners and post-translational modifications of the FA core complex. Immunoprecipitation of FANCA or FANCD2 followed by western blotting for ubiquitin can detect monoubiquitylation.
Transcriptomics and RNA-seq
RNA sequencing can reveal transcriptional changes in FA core subunit genes under different conditions, such as TSN overexpression or JAK/STAT1 activation. This helps identify regulatory mechanisms and downstream effects on mRNA export.
CRISPR Screening
Genome-wide CRISPR knockout screens can identify synthetic lethal interactions with FA core complex mutations, revealing potential therapeutic targets. These screens are powerful for uncovering genes that become essential when the FA pathway is defective.
How CRISPR Can Be Used to Study GO:0043240 Fanconi anaemia nuclear complex
Knockout
CRISPR knockout of FA core genes (e.g., FANCA, FANCC) creates isogenic cell lines to study loss of FANCD2 monoubiquitylation and increased sensitivity to DNA crosslinking agents. These models are valuable for dissecting the role of the complex in DNA repair and for drug screening.
Point Mutation
Point mutations can be introduced into catalytic residues of FANCL or interaction domains of FANCA to separate ubiquitin ligase activity from complex assembly. Such models help define structure-function relationships within the complex.
Knock-in
Knock-in of tagged FANCD2 or FANCI (e.g., GFP or HA) allows visualization and quantification of monoubiquitylation and chromatin recruitment in live cells. This approach is useful for studying dynamics of the FA pathway.
Overexpression
Overexpression of FA core subunits or regulators like TSN can model pathway hyperactivation or repression, as seen in cancers. Overexpression models are used to test whether increased levels alter DNA repair capacity or chemosensitivity.
How EDITGENE Supports Fanconi anaemia nuclear complex Research
Researchers studying Fanconi anaemia nuclear complex-related genes often need to determine whether a candidate gene is causally involved in DNA repair, chromosome stability, or disease progression. EDITGENE provides a comprehensive suite of CRISPR-based services to enable such functional studies.
Contact EDITGENE today to design your custom CRISPR model for Fanconi anaemia nuclear complex research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| FANCC Knockout HEK293 Cell Line | EDJ-KQ2465 | Human | 2176 | Details Get a Quote |
| FANCG Knockout HEK293 Cell Line | EDJ-KQ3404 | Human | 2189 | Details Get a Quote |
| FANCE Knockout HEK293 Cell Line | EDJ-KQ4574 | Human | 2178 | Details Get a Quote |
| FANCB Knockout HEK293 Cell Line | EDJ-KQ4577 | Human | 2187 | Details Get a Quote |
| CENPX Knockout HEK293 Cell Line | EDJ-KQ4785 | Human | 201254 | Details Get a Quote |
| FAAP100 Knockout HEK293 Cell Line | EDJ-KQ9497 | Human | 80233 | Details Get a Quote |
| FAAP24 Knockout HEK293 Cell Line | EDJ-KQ10736 | Human | 91442 | Details Get a Quote |
| FANCM Knockout HEK293 Cell Line | EDJ-KQ11356 | Human | 57697 | Details Get a Quote |
| FAAP20 Knockout HEK293 Cell Line | EDJ-KQ11713 | Human | 199990 | Details Get a Quote |
| CENPS Knockout HEK293 Cell Line | EDJ-KQ12860 | Human | 378708 | Details Get a Quote |
| FANCA Knockout HEK293 Cell Line | EDJ-KQ13446 | Human | 2175 | Details Get a Quote |
| FANCL Knockout HEK293 Cell Line | EDJ-KQ13448 | Human | 55120 | Details Get a Quote |
| FANCG Knockout A-549 Cell Line | EDJ-KQ25106 | Human | 2189 | Details Get a Quote |
| FANCG Knockout HCT 116 Cell Line | EDJ-KQ25107 | Human | 2189 | Details Get a Quote |
| FANCG Knockout HeLa Cell Line | EDJ-KQ25108 | Human | 2189 | Details Get a Quote |
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Frequently Asked Questions About Fanconi anaemia nuclear complex
What is the Fanconi anaemia nuclear complex?
It is a protein complex (GO:0043240) composed of FA core proteins that activates FANCD2 by monoubiquitylation and protects against chromosome breakage.
What genes are involved in the Fanconi anaemia nuclear complex?
Key genes include FANCA, FANCC, FANCE, FANCF, FANCG, and FANCL, along with accessory proteins.
What is the function of GO:0043240?
It functions in the monoubiquitylation of FANCD2 and in promoting homologous recombination and genome stability.
How is the Fanconi anaemia nuclear complex regulated?
It is regulated by DNA damage, transcriptional repression (e.g., by TSN via JAK/STAT1), and post-translational modifications.
What diseases are associated with the Fanconi anaemia nuclear complex?
Fanconi anaemia, bone marrow failure, and various cancers including bladder cancer and leukemia.
What experimental models are used to study GO:0043240?
CRISPR knockout, point mutation, knock-in, and overexpression cell lines, as well as DNA repair assays and CRISPR screens.
How can I knockout FANCA in my cell line?
EDITGENE provides validated CRISPR knockout services for FANCA and other FA genes, with functional verification.
What is the role of FANCD2 monoubiquitylation?
It is a critical activation step for the FA pathway, required for DNA repair and chromosome stability.
Can I use CRISPR screening to find synthetic lethal targets with FA mutations?
Yes, genome-wide CRISPR screens can identify genes that are essential in FA-deficient cells, revealing therapeutic targets.
What bioinformatics tools are available for FA pathway analysis?
EDITGENE offers integrated bioinformatics for CRISPR screen analysis, RNA-seq, and proteomics to study FA core complex regulation.
Conclusion
The Fanconi anaemia nuclear complex (GO:0043240) is a central hub in the DNA damage response, essential for FANCD2 monoubiquitylation, homologous recombination, and genome stability. Its dysfunction causes Fanconi anaemia and predisposes to cancer, making it a critical area of research. Advanced CRISPR models and functional assays are key to unraveling its mechanisms and identifying therapeutic opportunities.
References
- 1. van de Kooij B et al.. 2024. The Fanconi anemia core complex promotes CtIP-dependent end resection to drive homologous recombination at DNA double-strand breaks.. Nat Commun 15(1):7076 PMID: 39152113
- 2. Zhao W et al.. 2025. TSN Disrupts Fanconi Anemia Pathway Activation Through JAK/STAT1-Mediated Transcriptional Repression of FA Core Subunits in Bladder Cancer.. Dose Response 23(4):15593258251406039 PMID: 41346410
- 3. Bagby GC et al.. 2006. Fanconi anemia.. Semin Hematol 43(3):147-56 PMID: 16822457
- 4. Her J et al.. 2024. RNF4 sustains Myc-driven tumorigenesis by facilitating DNA replication.. J Clin Invest 134(10) PMID: 38530355
- 5. Olazabal-Herrero A et al.. 2024. The FANCI/FANCD2 complex links DNA damage response to R-loop regulation through SRSF1-mediated mRNA export.. Cell Rep 43(1):113610 PMID: 38165804
- 6. Zhu G et al.. 2025. Defective Microhomology-Mediated End-joining in SMARCB1-Deficient Tumors.. bioRxiv PMID: 41332615
- 7. Stanage TH et al.. 2026. RPA exhaustion activates SLFN11 to eliminate cells with heightened replication stress.. Nat Cell Biol 28(2):240-254 PMID: 41514018
- 8. Grompe M et al.. 2001. Fanconi anemia and DNA repair.. Hum Mol Genet 10(20):2253-9 PMID: 11673408
