GO:0044547 DNA topoisomerase binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0044547 DNA topoisomerase binding is a molecular function describing the selective interaction of a protein with a DNA topoisomerase enzyme.
• DNA topoisomerases are essential enzymes that resolve topological stress in DNA during replication, transcription, and recombination.
• Binding to topoisomerases can regulate their catalytic activity, subcellular localization, and stability, as shown for human topoisomerase I.
• The interaction is often DNA-dependent, with preferential binding to superhelical DNA or specific DNA structures.
• Dysregulation of topoisomerase binding is implicated in cancer and is a target for chemotherapeutic agents like camptothecin.
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) enable functional dissection of topoisomerase-binding interfaces.
Description
DNA topoisomerase binding (GO:0044547) is a molecular function defined as the selective interaction of a protein with a DNA topoisomerase enzyme. This binding event is critical for regulating the catalytic cycle of topoisomerases, which manage DNA topology during essential processes such as replication, transcription, and chromosome segregation. The function is not limited to a single protein but encompasses any protein that physically associates with a topoisomerase, including regulatory subunits, viral proteins, and therapeutic compounds. Understanding this binding is fundamental to deciphering how cells maintain genomic integrity and how perturbations contribute to disease. Researchers study DNA topoisomerase binding to uncover mechanisms of enzyme regulation, to identify drug targets, and to map interaction networks genome-wide.
DNA topoisomerase binding At A Glance
| GO ID | GO:0044547 |
|---|---|
| GO term | DNA topoisomerase binding |
| Ontology | molecular_function |
| Synonym | DNA topoisomerase I binding |
| Definition | Binding to a DNA topoisomerase. |
| Major function | Regulation of topoisomerase activity and localization |
| Related processes | DNA replication, transcription, recombination |
| Disease relevance | Cancer, viral infections, neurodegeneration |
What Is GO:0044547?
DNA topoisomerase binding (GO:0044547) refers to the ability of a protein or molecule to selectively interact with a DNA topoisomerase enzyme. This binding can occur in the presence or absence of DNA and may modulate the topoisomerase's catalytic activity, its recruitment to specific genomic loci, or its stability. The term encompasses both transient and stable interactions and is distinct from the catalytic activity of the topoisomerase itself.
Why Is DNA topoisomerase binding Important in Cell Biology?
DNA topoisomerase binding is important because it directly influences the activity of topoisomerases, enzymes that are indispensable for resolving DNA topological stress during replication and transcription. Dysregulation of these interactions can lead to genomic instability, which is a hallmark of cancer and other diseases. Moreover, topoisomerase-binding proteins and drugs are clinically relevant: camptothecin and its derivatives stabilize the topoisomerase I-DNA cleavage complex, leading to cytotoxic DNA damage in cancer cells. Studying this binding function provides insights into fundamental DNA metabolism and offers opportunities for therapeutic intervention.
• Regulates topoisomerase catalytic activity and prevents hypertranscription.
• Essential for resolving DNA supercoiling during replication and transcription.
• Targeted by anticancer drugs such as camptothecin.
• Involved in viral DNA replication, e.g., vaccinia virus topoisomerase I.
• Modulates genome-wide topoisomerase binding and cleavage sites.
• Preferential binding to superhelical DNA affects topoisomerase I function.
• Contributes to transcriptional repression and safeguarding against hypertranscription.
• Potential biomarker for cancer prognosis and drug response.
• Enables mapping of topoisomerase interaction networks via NGS.
• Provides a basis for CRISPR screens to identify regulatory components.
Molecular Mechanism of DNA topoisomerase binding
Substrate Recognition and DNA Dependence
In simple terms: The binding protein recognizes the topoisomerase enzyme, often when it is bound to DNA.
DNA topoisomerase binding frequently depends on the presence of DNA, as the topoisomerase may undergo conformational changes upon DNA binding that create or expose interaction surfaces. For example, human topoisomerase I preferentially binds to superhelical DNA, and this binding is influenced by the DNA topology. Vaccinia virus DNA topoisomerase I forms specific DNA cleavage and binding complexes, which can be recognized by interacting proteins.
Binding Interfaces and Structural Determinants
In simple terms: Specific shapes and charges on the topoisomerase and its partner determine how they stick together.
Structural studies of topoisomerase V in complex with DNA reveal unusual DNA-binding modes that could affect protein-protein interactions. The binding interface often involves electrostatic interactions and shape complementarity, as seen in the binding of camptothecin to the topoisomerase I-DNA covalent binary complex. These structural features are critical for the specificity of GO:0044547.
Regulation of Topoisomerase Activity
In simple terms: Binding can turn the topoisomerase on or off, or change what it does.
Binding partners can modulate topoisomerase catalysis. A secondary DNA binding surface of DNA topoisomerase I mediates transcriptional repression, safeguarding against hypertranscription. This indicates that binding events can allosterically regulate the enzyme's function beyond simple recruitment.
Genome-Wide Mapping of Binding Sites
In simple terms: New sequencing methods let scientists see everywhere a topoisomerase binds across the genome.
Next-generation sequencing techniques have been developed to map DNA topoisomerase binding and cleavage genome-wide, providing a comprehensive view of where these interactions occur. Such maps reveal that binding is not random but enriched at specific genomic regions, often correlating with transcriptional activity.
Pharmacological Interference
In simple terms: Drugs can block or stabilize the binding between topoisomerases and their partners.
Camptothecin and its derivatives bind to the topoisomerase I-DNA covalent binary complex, stabilizing it and converting the enzyme into a DNA-damaging agent. This demonstrates that small molecules can target the binding interface and is a paradigm for drug discovery targeting GO:0044547.
Key Genes Involved in GO:0044547 DNA topoisomerase binding
The following genes and proteins are experimentally validated to be involved in DNA topoisomerase binding or to serve as topoisomerases that are bound by other factors.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TOP1 | Human DNA topoisomerase I; binds DNA and is target of camptothecin | Key enzyme in DNA relaxation; binding regulates transcription |
| TOP2A | Human DNA topoisomerase II alpha; resolves DNA catenanes | Target of etoposide; binding affects replication |
| TOP2B | Human DNA topoisomerase II beta; involved in transcription | Binding partners modulate neuronal gene expression |
| TOP3A | Human DNA topoisomerase III alpha; resolves Holliday junctions | Binding regulates genome stability |
| TOP3B | Human DNA topoisomerase III beta; RNA topoisomerase | Binding implicated in neurodevelopment |
| TOP1MT | Mitochondrial DNA topoisomerase I | Binding affects mitochondrial DNA replication |
| TOPOV | Topoisomerase V from Methanopyrus kandleri | Unusual DNA-binding mode; model for binding studies |
| VACV TOP1 | Vaccinia virus DNA topoisomerase I | Viral enzyme; binding studied for antiviral targets |
| TPT1 | Tumor protein, translationally-controlled 1; interacts with topoisomerase I | Potential regulator of topoisomerase I binding |
| PARP1 | Poly(ADP-ribose) polymerase 1; binds topoisomerases | Involved in DNA damage response |
| XRCC1 | X-ray repair cross-complementing 1; interacts with topoisomerases | DNA repair factor; binding affects repair |
| BLM | Bloom syndrome RecQ helicase; binds topoisomerases | Maintains genome stability |
| WRN | Werner syndrome RecQ helicase; binds topoisomerases | Premature aging and cancer |
| p53 | Tumor suppressor; binds topoisomerase I | Regulates topoisomerase I activity |
| HSP90 | Heat shock protein 90; binds topoisomerase II | Chaperone for topoisomerase stability |
| SUMO1 | Small ubiquitin-like modifier; modifies topoisomerases | Regulates binding interactions |
| UBE2I | SUMO-conjugating enzyme UBC9; sumoylates topoisomerases | Modifies topoisomerase binding |
How Is DNA topoisomerase binding Regulated?
DNA topoisomerase binding is regulated at multiple levels. Post-translational modifications such as SUMOylation can alter the interaction between topoisomerases and their binding partners. Transcriptional repression by a secondary DNA binding surface of DNA topoisomerase I safeguards against hypertranscription, indicating autoregulatory feedback. Additionally, the binding of camptothecin to the topoisomerase I-DNA complex demonstrates that small molecules can modulate these interactions. Cellular stress and DNA damage can also influence binding dynamics, as topoisomerases are recruited to sites of damage.
DNA topoisomerase binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TOP1 | Cancer; camptothecin sensitivity | Knockout and point-mutation cell lines |
| TOP2B | Neurodegeneration; neuronal transcription | Conditional knockout in neurons |
| TOP3B | Neurodevelopmental disorders | Knock-in of patient mutations |
| VACV TOP1 | Viral replication | Infection models with tagged topoisomerase |
| TOP1MT | Mitochondrial dysfunction | Mitochondria-targeted knockout |
Cancer
Dysregulated DNA topoisomerase binding contributes to cancer through genomic instability. Topoisomerase I is overexpressed in many cancers, and its binding to DNA and inhibitors like camptothecin is exploited in chemotherapy. Mutations in topoisomerase-binding interfaces can lead to altered enzyme activity, promoting tumorigenesis.
Neurodegeneration
Topoisomerase II beta (TOP2B) binding is critical for neuronal gene expression, and its dysfunction is linked to neurodegeneration. Similarly, TOP3B mutations affecting binding are associated with neurodevelopmental disorders.
Viral Infections
Viral topoisomerases, such as vaccinia virus DNA topoisomerase I, require specific binding to DNA and host factors for viral replication. Targeting these binding interactions is a potential antiviral strategy.
From DNA topoisomerase binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a topoisomerase-binding protein affect enzyme activity? | Knockout cell line (CRISPR-Cas9) |
| Does a specific point mutation in the binding interface disrupt interaction? | Point-mutation knock-in via HDR |
| Can a tagged topoisomerase rescue binding in live cells? | Tagged knock-in (e.g., GFP, HA) |
| Does overexpression of a binding partner alter drug sensitivity? | Overexpression stable cell line |
| Which genes regulate topoisomerase binding genome-wide? | CRISPR library screening |
| What is the genome-wide binding profile of topoisomerase I? | Next-generation sequencing (ChIP-seq, Topo-seq) |
How to Study the DNA topoisomerase binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| ChIP-seq | Genome-wide binding sites of topoisomerases | Mapping TOP1 binding across genome |
| EMSA | Direct protein-DNA or protein-protein binding | Assessing topoisomerase I binding to superhelical DNA |
| SPR | Binding kinetics and affinity | Quantifying camptothecin-topoisomerase interaction |
| X-ray crystallography | 3D structure of binding complexes | Visualizing topoisomerase V-DNA complex |
| CRISPR knockout screen | Genes affecting topoisomerase binding | Identifying regulators of drug sensitivity |
| Co-immunoprecipitation | Protein-protein interactions | Detecting topoisomerase I binding partners |
| FRET | Dynamic binding in live cells | Monitoring topoisomerase I conformational changes |
| Next-generation sequencing | Topoisomerase cleavage sites | Genome-wide mapping of cleavage |
Genome-Wide Binding Mapping
Next-generation sequencing techniques such as ChIP-seq and Topo-seq enable genome-wide mapping of DNA topoisomerase binding and cleavage sites. These methods provide base-pair resolution of binding events and reveal enrichment at active promoters and enhancers.
Biochemical Binding Assays
Electrophoretic mobility shift assays (EMSA) and surface plasmon resonance (SPR) can measure direct binding between topoisomerases and partner proteins or DNA. These assays are used to determine affinity and specificity of interactions.
Structural Biology
X-ray crystallography and cryo-electron microscopy have revealed the structural basis of topoisomerase binding, including unusual DNA-binding modes in topoisomerase V. These structures inform drug design targeting binding interfaces.
CRISPR Screens
Pooled CRISPR knockout screens can identify genes that regulate topoisomerase binding and sensitivity to topoisomerase poisons. Such screens are powerful for discovering novel components of the binding network.
How CRISPR Can Be Used to Study GO:0044547 DNA topoisomerase binding
Knockout
CRISPR-Cas9 knockout of genes encoding topoisomerase-binding proteins can reveal their necessity for topoisomerase function. For example, knocking out a candidate binding partner may lead to altered topoisomerase I activity and increased sensitivity to camptothecin.
Point Mutation
Introducing point mutations in the binding interface of a topoisomerase or its partner via CRISPR base editing or HDR can dissect the functional significance of specific residues. This approach has been used to study the secondary DNA binding surface of topoisomerase I.
Knock-in
Tagged knock-in of topoisomerases (e.g., GFP or HA) allows live-cell imaging and proteomic analysis of binding complexes. This is valuable for mapping dynamic interactions genome-wide.
Overexpression
CRISPR activation (CRISPRa) or cDNA overexpression can drive high levels of a binding partner to test for gain-of-function effects on topoisomerase activity and drug response.
How EDITGENE Supports DNA topoisomerase binding Research
Researchers studying DNA topoisomerase binding-related genes often need to determine whether a candidate gene is causally involved in topoisomerase regulation, drug sensitivity, or genome stability. EDITGENE provides a comprehensive suite of CRISPR-based services to accelerate this research, from gene knockout to precise point mutations and library screens.
Contact EDITGENE today to design your custom CRISPR model for DNA topoisomerase binding research.
Frequently Asked Questions About DNA topoisomerase binding
What is DNA topoisomerase binding?
DNA topoisomerase binding (GO:0044547) is the molecular function of selectively interacting with a DNA topoisomerase enzyme, which can regulate its activity and localization.
What genes are involved in DNA topoisomerase binding?
Genes encoding topoisomerases (TOP1, TOP2A, TOP2B, TOP3A, TOP3B, TOP1MT) and their binding partners such as PARP1, p53, and BLM are involved.
How does DNA topoisomerase binding affect cancer?
Dysregulated binding can lead to genomic instability and is targeted by anticancer drugs like camptothecin, which stabilizes the topoisomerase I-DNA complex.
What methods are used to study DNA topoisomerase binding?
Common methods include ChIP-seq, EMSA, SPR, X-ray crystallography, and CRISPR screens.
What is the role of TOP1 in DNA topoisomerase binding?
TOP1 (DNA topoisomerase I) binds to superhelical DNA and is regulated by secondary DNA binding surfaces that repress transcription.
Can CRISPR be used to study DNA topoisomerase binding?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models enable functional dissection of binding interfaces and regulators.
What diseases are linked to DNA topoisomerase binding?
Cancer, neurodegeneration, and viral infections are linked to altered topoisomerase binding.
How is DNA topoisomerase binding regulated?
It is regulated by post-translational modifications (e.g., SUMOylation), DNA topology, and small molecules like camptothecin.
What is the difference between DNA topoisomerase binding and topoisomerase activity?
Binding refers to the interaction with the enzyme, while activity refers to the catalytic relaxation of DNA; binding can modulate activity.
Where can I find genome-wide maps of DNA topoisomerase binding?
Next-generation sequencing techniques such as Topo-seq and ChIP-seq provide genome-wide maps.
Conclusion
DNA topoisomerase binding (GO:0044547) is a fundamental molecular function that regulates the activity of topoisomerases, enzymes critical for DNA metabolism. Its dysregulation is implicated in cancer, neurodegeneration, and viral infections, making it a prime target for therapeutic intervention. Advances in CRISPR-based models and genome-wide sequencing continue to unravel the complex network of proteins and mechanisms that govern this binding, offering new avenues for research and drug discovery.
References
- 1. McKie SJ et al.. 2020. Mapping DNA Topoisomerase Binding and Cleavage Genome Wide Using Next-Generation Sequencing Techniques.. Genes (Basel) 11(1) PMID: 31941152
- 2. Champoux JJ. 2001. DNA topoisomerases: structure, function, and mechanism.. Annu Rev Biochem 70:369-413 PMID: 11395412
- 4. Osterman A et al.. 2022. Structures of topoisomerase V in complex with DNA reveal unusual DNA-binding mode and novel relaxation mechanism.. Elife 11 PMID: 35969036
- 5. Shuman S et al.. 1990. Specific DNA cleavage and binding by vaccinia virus DNA topoisomerase I.. J Biol Chem 265(29):17826-36 PMID: 2170398
- 6. Hecht SM. 2005. Camptothecin: roles of the D and E rings in binding to the topoisomerase I-DNA covalent binary complex.. Curr Med Chem Anticancer Agents 5(4):353-62 PMID: 16101487
- 7. Lau MS et al.. 2023. Transcriptional repression by a secondary DNA binding surface of DNA topoisomerase I safeguards against hypertranscription.. Nat Commun 14(1):6464 PMID: 37833256
- 8. Madden KR et al.. 1995. Preferential binding of human topoisomerase I to superhelical DNA.. EMBO J 14(21):5399-409 PMID: 7489729
