GO:0071667 DNA/RNA hybrid binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0071667 DNA/RNA hybrid binding is a molecular function defined as binding to an RNA/DNA hybrid, also known as an R-loop.
• DNA/RNA hybrids are non-canonical nucleic acid structures that form co-transcriptionally and are recognized by dedicated sensor proteins.
• Native R-loop profiling with a DNA-RNA hybrid recognition sensor (S9.6) has revealed thousands of hybrid sites across the genome.
• The INTS6-SOSS1 tetrameric complex facilitates DNA:RNA hybrid autoregulation at double-strand breaks, linking hybrid binding to genome stability.
• DDX17 is required for efficient DSB repair at DNA:RNA hybrid deficient loci, demonstrating a direct role for hybrid-binding helicases in DNA repair.
• Hybrid binding is studied using docking, strand-displacement kinetics, force spectroscopy, and CRISPR-based perturbation of sensor genes [1,4,6].
Description
DNA/RNA hybrid binding (GO:0071667) is the molecular function of selectively associating with a duplex formed between a DNA strand and a complementary RNA strand. Such hybrids arise naturally during transcription, when the nascent RNA anneals to the template DNA strand, creating a three-stranded structure called an R-loop. The functional importance of this binding activity is underscored by the existence of specialized protein domains and sensors that recognize the hybrid geometry rather than single-stranded or double-stranded nucleic acids. Researchers study this term because hybrid-binding proteins regulate transcription, DNA repair, and genome stability, and their dysfunction is increasingly linked to human disease [3,8]. The QuickGO definition states that this function is simply binding to a RNA/DNA hybrid, but the biological consequences of that binding are broad and mechanistically rich [2,3].
DNA/RNA hybrid binding At A Glance
| GO ID | GO:0071667 |
|---|---|
| GO term | DNA/RNA hybrid binding |
| Ontology | molecular_function |
| Synonym | RNA/DNA hybrid binding |
| Major function | Selective binding to a duplex formed by one RNA strand and one DNA strand |
| Common detection | S9.6 antibody or DNA-RNA hybrid recognition sensor |
| Related structures | R-loops, co-transcriptional hybrids, DNA:RNA hybrid G-quadruplexes [2,5] |
| Representative proteins | DDX17, INTS6, SOSS1, zinc-finger hybrid binders [3,7,8] |
| Disease relevance | Genome instability, DSB repair defects, cancer and neurodegeneration [3,8] |
What Is GO:0071667?
GO:0071667 DNA/RNA hybrid binding describes the selective and non-covalent interaction of a protein or protein complex with a nucleic acid duplex composed of one RNA strand and one DNA strand. This is a molecular function annotation: it captures the binding event itself, not the downstream process. The synonym RNA/DNA hybrid binding is used interchangeably. In practice, this function is often detected using the S9.6 antibody or a DNA-RNA hybrid recognition sensor that specifically recognizes the hybrid conformation. The binding can be sequence-independent or can show preferences for particular hybrid lengths, sequences, or topological contexts, and it can be coupled to enzymatic activities such as helicase or nuclease action [3,8].
Why Is DNA/RNA hybrid binding Important in Cell Biology?
DNA/RNA hybrid binding is important because hybrids are not merely transient byproducts of transcription; they are regulated structural intermediates that influence gene expression, DNA repair, and genome integrity [2,3]. Proteins that bind hybrids can either stabilize or resolve them, and the balance between these activities determines whether an R-loop becomes a source of replication stress or a platform for repair factor recruitment [3,8]. Because hybrid-binding proteins are tractable drug targets and their loss produces measurable phenotypes in cell models, GO:0071667 is a high-value annotation for functional genomics and disease research [2,8].
• R-loops are abundant genomic features that can be mapped genome-wide using hybrid recognition sensors.
• Hybrid binding at double-strand breaks contributes to autoregulation of DNA:RNA hybrid levels.
• DDX17 helicase activity at hybrid-deficient loci is required for efficient DSB repair.
• Hybrid strand displacement kinetics determine how quickly regulatory RNAs can be released or exchanged.
• DNA:RNA hybrid G-quadruplex stability affects folding and unfolding pathways relevant to gene regulation.
• The elasticity of DNA, RNA, and hybrid double helices differs, influencing protein recognition and mechanics.
• Engineered zinc fingers can be evolved to improve DNA-RNA binding selectivity.
• Hybrid-binding proteins are candidate biomarkers and therapeutic targets in cancer and neurological disease [3,8].
Molecular Mechanism of DNA/RNA hybrid binding
Hybrid formation and recognition
In simple terms: First, an RNA strand pairs with a DNA strand to make a hybrid, and then a protein recognizes that hybrid shape.
DNA/RNA hybrids form when a nascent RNA anneals to the template DNA strand during transcription, creating an R-loop. Genome-wide profiling with a DNA-RNA hybrid recognition sensor has shown that these structures occur at thousands of native sites. Recognition depends on the unique geometry of the hybrid duplex, which differs from both B-form DNA and A-form RNA.
Binding affinity and strand displacement
In simple terms: Proteins that bind hybrids must also let go or exchange strands at the right time, which is governed by kinetics.
The kinetics of RNA and RNA:DNA hybrid strand displacement determine how rapidly a bound hybrid can be remodeled. These rates influence whether a hybrid is transient or persistent, and therefore whether it recruits repair or transcription factors. Hybrid G-quadruplexes add further complexity because their stability and unfolding pathways differ from simple duplexes.
Protein domains and engineered binders
In simple terms: Certain protein folds, such as zinc fingers, can be engineered to grip DNA-RNA hybrids more selectively.
Directed evolution has been used to improve the selectivity of a DNA-RNA binding zinc finger, showing that hybrid recognition can be tuned at the domain level. Computational docking tools such as HDOCK enable modeling of protein-DNA/RNA hybrid interactions to guide mutagenesis. These approaches help identify the residues that contact the hybrid duplex [1,7].
Coupling to DNA repair and genome stability
In simple terms: Once a protein binds a hybrid, it can recruit repair machinery or resolve the hybrid to protect the genome.
The tetrameric INTS6-SOSS1 complex facilitates DNA:RNA hybrid autoregulation at double-strand breaks, linking hybrid binding to break repair. DDX17 is required for efficient DSB repair at DNA:RNA hybrid deficient loci, demonstrating that hybrid-binding helicases act directly in the repair pathway. Together, these findings show that hybrid binding is not passive but is coupled to catalytic and signaling outcomes [3,8].
Biophysical determinants of hybrid recognition
In simple terms: The physical stiffness and flexibility of the hybrid helix affect how proteins can bind it.
Temperature-dependent elasticity measurements show that DNA, RNA, and hybrid double helices have distinct mechanical properties. These differences can influence the energy cost of bending or unwinding a hybrid during protein binding. Such biophysical parameters are essential for interpreting hybrid-binding assays and for designing hybrid-mimetic probes [4,6].
Key Genes Involved in GO:0071667 DNA/RNA hybrid binding
The following genes and protein complexes represent major experimental handles for studying DNA/RNA hybrid binding (GO:0071667) in human cells.
| Gene | Major Role | Research Relevance |
|---|---|---|
| DDX17 | RNA helicase required for DSB repair at hybrid-deficient loci | Knockout reduces repair efficiency; used to study hybrid-dependent repair |
| INTS6 | Component of the INTS6-SOSS1 tetrameric complex | Regulates DNA:RNA hybrid autoregulation at DSBs |
| SOSS1 | Oligosaccharide-binding component of the INTS6-SOSS1 complex | Facilitates hybrid autoregulation at double-strand breaks |
| S9.6-like sensor | Antibody or engineered sensor that binds DNA-RNA hybrids | Used for native R-loop profiling |
| Zinc-finger hybrid binders | Engineered domains with tunable DNA-RNA selectivity | Directed evolution improves hybrid binding specificity |
| HDOCK-modeled proteins | Computational docking targets for hybrid binding | Predicts protein-DNA/RNA hybrid interfaces |
| Hybrid G-quadruplex binders | Proteins that recognize DNA:RNA hybrid G-quadruplexes | Linked to stability and unfolding studies |
| Strand-displacement factors | Proteins that exchange RNA and RNA:DNA hybrids | Kinetic studies inform hybrid turnover |
| Elasticity probes | Proteins or polymers used to measure hybrid stiffness | Biophysical characterization of hybrid duplexes |
| R-loop sensor proteins | Endogenous proteins that recognize R-loops | Genome-wide mapping of hybrid sites |
| DSB repair factors | Proteins recruited to breaks via hybrid binding | Functional assays for genome stability [3,8] |
| Transcription elongation factors | Proteins that encounter hybrids during transcription | R-loop formation and resolution studies |
| RNA processing factors | Proteins that bind hybrids during splicing or polyadenylation | Potential crosstalk with hybrid metabolism |
| Helicase family members | Enzymes that unwind DNA/RNA hybrids | Targets for KO and point-mutation studies |
| Nuclease-associated binders | Proteins that couple hybrid binding to cleavage | Relevant to hybrid resolution and genome stability |
| Engineered hybrid probes | Synthetic binders for imaging or pull-down | Tool development for hybrid detection [2,7] |
How Is DNA/RNA hybrid binding Regulated?
DNA/RNA hybrid binding is regulated at multiple levels. The abundance of hybrid substrates is controlled by transcription and by the opposing activities of hybrid-stabilizing and hybrid-resolving factors. At double-strand breaks, the INTS6-SOSS1 complex provides autoregulation of DNA:RNA hybrid levels, suggesting a feedback loop that adjusts hybrid binding capacity to repair demand. DDX17 helicase activity is required for efficient DSB repair specifically at hybrid-deficient loci, indicating that hybrid binding and resolution are coordinated with the repair machinery. Biophysical parameters such as hybrid stability and strand-displacement kinetics also set the effective lifetime of a binding event, thereby influencing regulation [4,5].
DNA/RNA hybrid binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| DDX17 | Defective DSB repair and genome instability | Knockout and point-mutation cell lines |
| INTS6 | Impaired hybrid autoregulation at DSBs | Knockout and tagged knock-in models |
| SOSS1 | DSB repair deficiency | Knock-in and overexpression models |
| Zinc-finger hybrid binders | Engineered hybrid detection and targeting | Directed evolution and overexpression |
| Hybrid G-quadruplex binders | Hybrid stability-related dysfunction | Biophysical and knock-in models |
Genome instability and cancer
Persistent DNA/RNA hybrids can cause replication stress and DNA damage, and proteins that bind or resolve them are frequently altered in cancer [2,3]. The INTS6-SOSS1 complex acts at double-strand breaks to autoregulate hybrids, and its dysfunction could impair repair fidelity. DDX17 loss reduces DSB repair efficiency at hybrid-deficient loci, providing a mechanistic link between hybrid binding and genome stability.
Neurological and developmental disorders
R-loop accumulation has been associated with neurological dysfunction in multiple contexts, and hybrid-binding proteins are candidate modifiers. Because hybrid recognition sensors can map R-loops genome-wide, they offer a route to identify disease-relevant hybrid sites. Engineered hybrid binders with improved selectivity may help dissect these mechanisms.
Therapeutic targeting of hybrid-binding proteins
Hybrid-binding domains are attractive drug targets because they can be inhibited or redirected with small molecules or engineered proteins. Computational docking of protein-DNA/RNA hybrids supports structure-guided design of such inhibitors. Kinetic and biophysical studies provide the parameters needed to optimize hybrid-targeting therapeutics [4,6].
From DNA/RNA hybrid binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is DDX17 required for DSB repair at hybrid-deficient loci? | DDX17 knockout cell line |
| Does INTS6-SOSS1 autoregulate hybrids at DSBs? | INTS6 or SOSS1 knockout and tagged knock-in |
| Can zinc-finger hybrid selectivity be improved? | Directed evolution with point mutations |
| Where are native R-loops located genome-wide? | Hybrid recognition sensor profiling |
| How fast are hybrids displaced? | Strand-displacement kinetics assays |
| How stiff are DNA/RNA hybrids? | Temperature-dependent elasticity measurements |
How to Study the DNA/RNA hybrid binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Hybrid recognition sensor profiling | Genome-wide R-loop locations | Native R-loop mapping |
| Strand-displacement kinetics | Rate of RNA/RNA:DNA exchange | Hybrid turnover studies |
| Temperature-dependent elasticity | Mechanical stiffness of duplexes | Biophysical characterization |
| Hybrid G-quadruplex stability assays | Folding and unfolding energetics | Structural studies |
| HDOCK docking | Predicted protein-DNA/RNA interfaces | Structure-guided mutagenesis |
| Directed evolution | Improved hybrid binding selectivity | Engineered zinc fingers |
| DSB repair assays | Repair efficiency at hybrid loci | DDX17 and INTS6-SOSS1 studies [3,8] |
| CRISPR knockout/knock-in | Causal gene function | Hybrid-binding gene validation [3,8] |
Genome-wide hybrid mapping
Native R-loop profiling with a DNA-RNA hybrid recognition sensor enables genome-wide identification of hybrid sites. This approach is compatible with sequencing readouts and can be paired with CRISPR perturbation of candidate hybrid-binding genes.
Biophysical and kinetic characterization
Strand-displacement kinetics quantify how rapidly RNA and RNA:DNA hybrids exchange strands. Temperature-dependent elasticity measurements reveal the mechanical properties of DNA, RNA, and hybrid duplexes. Hybrid G-quadruplex stability and unfolding are studied with specialized folding assays.
Computational docking and design
HDOCK provides a hybrid strategy for protein-protein and protein-DNA/RNA docking, enabling structural hypotheses for hybrid binding. These models guide mutagenesis and engineered binder design [1,7].
Functional repair assays
DSB repair efficiency can be measured in cells lacking hybrid-binding proteins such as DDX17 or INTS6-SOSS1 components [3,8]. These assays connect hybrid binding to genome stability phenotypes [3,8].
How CRISPR Can Be Used to Study GO:0071667 DNA/RNA hybrid binding
Knockout
CRISPR knockout of DDX17 or INTS6-SOSS1 components can test whether hybrid binding is required for DSB repair and genome stability [3,8]. Knockout cell lines provide clean loss-of-function backgrounds for hybrid profiling.
Point Mutation
Point mutations in hybrid-binding domains can separate binding from catalysis, as shown for engineered zinc fingers with improved DNA-RNA selectivity. Such mutants help assign specific residues to hybrid recognition [1,7].
Knock-in
Tagged knock-in of INTS6 or SOSS1 enables localization and interaction studies at double-strand breaks. Knock-in of hybrid sensors can also create reporter systems for live-cell hybrid detection.
Overexpression
Overexpression of hybrid-binding proteins or engineered binders can test sufficiency for hybrid stabilization or repair recruitment [3,7]. Overexpression models are useful when endogenous levels are limiting.
How EDITGENE Supports DNA/RNA hybrid binding Research
Researchers studying DNA/RNA hybrid binding-related genes often need to determine whether a candidate gene is causally involved in hybrid recognition, resolution, or repair. EDITGENE provides CRISPR-edited cell models that let you move from correlation to causation with validated knockout, point-mutation, knock-in, and overexpression lines.
Contact EDITGENE today to design your custom CRISPR model for DNA/RNA hybrid binding research.
Frequently Asked Questions About DNA/RNA hybrid binding
What is GO:0071667 DNA/RNA hybrid binding?
GO:0071667 is a molecular function term describing the selective binding of a protein to a duplex formed by one RNA strand and one DNA strand, also called an R-loop or hybrid.
What genes are involved in DNA/RNA hybrid binding?
Key genes include DDX17, INTS6, and SOSS1, which have been functionally linked to hybrid recognition and DSB repair [3,8].
How are DNA/RNA hybrids detected in cells?
They are commonly detected with the S9.6 antibody or a DNA-RNA hybrid recognition sensor, which enables genome-wide profiling.
Why are DNA/RNA hybrids important for genome stability?
Persistent hybrids can cause replication stress, and hybrid-binding proteins such as DDX17 and INTS6-SOSS1 are required for efficient DSB repair [3,8].
What is the difference between DNA/RNA hybrid binding and R-loop binding?
R-loop binding typically refers to recognition of the three-stranded structure, whereas GO:0071667 specifically annotates binding to the RNA/DNA hybrid duplex itself.
Can DNA/RNA hybrid binding be studied with CRISPR?
Yes, knockout, point-mutation, knock-in, and overexpression models of hybrid-binding genes are used to test causality in repair and stability assays [3,8].
What methods measure hybrid binding affinity?
Strand-displacement kinetics, temperature-dependent elasticity, and hybrid G-quadruplex stability assays provide quantitative binding and mechanical parameters [4,5,6].
How does DDX17 function at DNA/RNA hybrids?
DDX17 is required for efficient DSB repair at DNA:RNA hybrid deficient loci, linking its helicase activity to hybrid-dependent repair.
What is the INTS6-SOSS1 complex?
It is a tetrameric complex that facilitates DNA:RNA hybrid autoregulation at double-strand breaks.
Can hybrid-binding proteins be engineered?
Yes, directed evolution has improved the selectivity of DNA-RNA binding zinc fingers, and docking tools guide such designs [1,7].
Conclusion
GO:0071667 DNA/RNA hybrid binding captures a molecular function that sits at the intersection of transcription, DNA repair, and genome stability [2,3]. The availability of hybrid recognition sensors, kinetic assays, and CRISPR-edited cell models makes it increasingly feasible to dissect how individual proteins recognize and act on RNA/DNA hybrids [2,4,8]. As the field moves toward therapeutic targeting of hybrid-binding proteins, validated functional models will be essential for translating binding data into disease relevance [3,7,8].
References
- 1. Yan Y et al.. 2017. HDOCK: a web server for protein-protein and protein-DNA/RNA docking based on a hybrid strategy.. Nucleic Acids Res 45(W1):W365-W373 PMID: 28521030
- 2. Wang K et al.. 2021. Genomic profiling of native R loops with a DNA-RNA hybrid recognition sensor.. Sci Adv 7(8) PMID: 33597247
- 3. Long Q et al.. 2024. Tetrameric INTS6-SOSS1 complex facilitates DNA:RNA hybrid autoregulation at double-strand breaks.. Nucleic Acids Res 52(21):13036-13056 PMID: 39445827
- 4. Liu H et al.. 2021. Kinetics of RNA and RNA:DNA Hybrid Strand Displacement.. ACS Synth Biol 10(11):3066-3073 PMID: 34752075
- 5. Zhang B et al.. 2025. The stability and unfolding of DNA: RNA hybrid G-quadruplexes.. Nucleic Acids Res 53(20) PMID: 41206036
- 6. Dohnalová H et al.. 2024. Temperature-dependent elasticity of DNA, RNA, and hybrid double helices.. Biophys J 123(5):572-583 PMID: 38340722
- 7. Sulej AA. 2019. Improving selectivity of DNA-RNA binding zinc finger using directed evolution.. BMC Res Notes 12(1):792 PMID: 31801592
- 8. Bader AS et al.. 2022. DDX17 is required for efficient DSB repair at DNA:RNA hybrid deficient loci.. Nucleic Acids Res 50(18):10487-10502 PMID: 36200807
