GO:0017150 tRNA dihydrouridine synthase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0017150 (tRNA dihydrouridine synthase activity) catalyzes the NAD(P)H-dependent reduction of uridine to 5,6-dihydrouridine in tRNA, a conserved modification that fine-tunes tRNA structure and translation.
• The Dus family (DusA, DusB, DusC in bacteria; DUS1, DUS2, DUS3, DUS4 in humans) forms a widespread enzyme family defined by a conserved FMN-binding TIM-barrel fold and a catalytic cysteine.
• Dihydrouridylation is redox-sensitive: the activity of Dus enzymes can be modulated by the cellular redox environment, linking tRNA modification to oxidative stress responses.
• Human DUS2 is overexpressed in lung cancer and interacts with the interferon-induced protein kinase PKR, connecting tRNA modification to tumorigenesis and innate immunity.
• DusA in bacteria uses a distinct mechanism to optimize tRNA for translation, and its loss affects translation efficiency and cellular fitness.
• Studying GO:0017150 requires combining biochemical assays, structural biology, and CRISPR-based models to dissect its roles in translation, stress response, and disease.
Description
tRNA dihydrouridine synthase activity (GO:0017150) is a molecular function that introduces the modified nucleoside 5,6-dihydrouridine (D) into tRNA. This modification is one of the most abundant in tRNA and is found across all domains of life, where it contributes to the structural stability and functional adaptability of the tRNA molecule. The enzyme catalyzes the NAD(P)H-dependent reduction of a uridine residue in tRNA to dihydrouridine, a reaction that requires a conserved FMN cofactor and a catalytic cysteine residue. Because dihydrouridine affects the flexibility of the tRNA backbone, its presence influences codon recognition, translation fidelity, and the overall efficiency of protein synthesis. Researchers study GO:0017150 not only to understand fundamental tRNA biology but also because defects in tRNA modification are increasingly linked to human diseases, including cancer, mitochondrial disorders, and neurological conditions. The dihydrouridine synthase (Dus) family was identified through bioinformatic and biochemical approaches, revealing multiple paralogs with distinct tRNA substrate specificities. In humans, DUS2 is associated with pulmonary carcinogenesis and interacts with the interferon-induced protein kinase PKR, suggesting a role in both cancer and antiviral responses. Recent work has also uncovered a connection between dihydrouridylation and oxidative stress, where the redox state of the cell modulates enzyme activity. This article provides a comprehensive overview of GO:0017150, covering its definition, catalytic mechanism, key genes, regulatory aspects, disease relevance, and the experimental methods used to study it. By integrating authoritative QuickGO data with verified PubMed literature, we aim to support researchers in designing experiments and interpreting data related to tRNA dihydrouridine synthase activity.
tRNA dihydrouridine synthase activity At A Glance
| GO ID | GO:0017150 |
|---|---|
| GO term | tRNA dihydrouridine synthase activity |
| Ontology | molecular_function |
| Synonym | (none) |
| Major function | Catalyzes the NAD(P)H-dependent reduction of uridine to 5,6-dihydrouridine in tRNA |
| Reaction | a 5,6-dihydrouridine in tRNA + NAD(P)+ = a uridine in tRNA + H+ + NAD(P)H |
| Cofactor | FMN (flavin mononucleotide) and NAD(P)H |
| Enzyme family | Dihydrouridine synthase (Dus) family, including DusA, DusB, DusC in bacteria and DUS1-4 in humans |
| Cellular role | tRNA modification, translation efficiency, stress response |
What Is GO:0017150?
According to the Gene Ontology, GO:0017150 (tRNA dihydrouridine synthase activity) is defined as the catalysis of the reaction: a 5,6-dihydrouridine in tRNA + NAD(P)+ = a uridine in tRNA + H+ + NAD(P)H. In other words, the enzyme uses NAD(P)H as a reducing agent to convert a uridine residue within a tRNA molecule into 5,6-dihydrouridine, thereby modifying the tRNA post-transcriptionally. This activity is essential for the proper folding and function of tRNA and is conserved from bacteria to humans.
Why Is tRNA dihydrouridine synthase activity Important in Cell Biology?
tRNA dihydrouridine synthase activity is important because it introduces a conserved modification that affects tRNA structure and function, thereby influencing translation efficiency and fidelity. Dihydrouridine is one of the most common tRNA modifications, and its presence is critical for maintaining the proper balance of protein synthesis, especially under stress conditions. In humans, dysregulation of DUS enzymes has been linked to cancer and other diseases, making this activity a potential therapeutic target. Understanding GO:0017150 also provides insights into fundamental RNA biology and the expanding field of epitranscriptomics.
• Dihydrouridylation enhances tRNA structural flexibility, which can affect codon-anticodon interactions and translation speed.
• The activity is conserved across all domains of life, highlighting its fundamental role in tRNA biology.
• Dus enzymes are redox-sensitive, linking tRNA modification to cellular oxidative stress responses.
• Human DUS2 is overexpressed in lung cancer and may serve as a biomarker or therapeutic target.
• DUS2 interacts with PKR, connecting tRNA modification to innate immunity and antiviral defense.
• Bacterial DusA has a distinct mechanism that optimizes tRNA for translation, making it a potential antibacterial target.
• Defects in tRNA modification can lead to mitochondrial dysfunction and neurological disorders.
• Studying GO:0017150 helps elucidate the role of tRNA modifications in gene expression regulation.
• Dihydrouridine synthases are attractive targets for drug development due to their essential roles in pathogens.
• The activity can be modulated by environmental factors such as temperature and redox state, as shown in extremophiles.
What Happens During tRNA dihydrouridine synthase activity?
Substrate recognition and binding
In simple terms: The enzyme finds and grabs a specific uridine in the tRNA molecule.
tRNA dihydrouridine synthases recognize their substrate tRNAs through specific structural features, often involving the D-arm and anticodon loop. The enzyme binds the tRNA and positions a target uridine residue into its active site. In Thermus thermophilus, the Dus enzyme exhibits high specificity for tRNA substrates, and its activity is optimal at high temperatures, reflecting the organism's extreme-thermophilic lifestyle. The molecular determinants of substrate specificity include conserved residues in the catalytic domain that interact with the tRNA backbone.
Catalytic reduction of uridine to dihydrouridine
In simple terms: The enzyme uses a chemical reaction to convert uridine into dihydrouridine.
The catalytic mechanism involves the transfer of hydride from NAD(P)H to the C5-C6 double bond of uridine, resulting in the formation of 5,6-dihydrouridine. This reaction requires the flavin mononucleotide (FMN) cofactor, which acts as an intermediate electron carrier. A conserved cysteine residue in the active site is essential for catalysis, as mutation of this residue abolishes activity. The reaction is stereospecific and generates dihydrouridine with a defined configuration.
Redox sensitivity and regulation
In simple terms: The enzyme's activity can be turned up or down by the cell's oxidative state.
Recent studies have shown that tRNA dihydrouridylation is sensitive to the cellular redox environment. The activity of Dus enzymes can be modulated by oxidative stress, and the redox state of the cell influences the levels of dihydrouridine in tRNA. This redox sensitivity may allow cells to rapidly adjust tRNA modification in response to changing conditions, linking translation to stress responses. In bacteria, the DusA enzyme has a distinct mechanism that optimizes tRNA for translation under specific growth conditions.
Impact on tRNA structure and translation
In simple terms: The modification changes the shape of tRNA, helping it work better in protein synthesis.
Dihydrouridine introduces a non-planar, flexible conformation into the tRNA backbone, which can affect the overall structure of the tRNA. This modification is often found in the D-loop and variable loop, where it contributes to the stabilization of the L-shaped tertiary structure. By altering tRNA flexibility, dihydrouridylation can influence codon-anticodon pairing and the rate of translation elongation. In human cells, DUS2-mediated modification of tRNA has been linked to efficient translation and cellular proliferation.
Key Genes Involved in GO:0017150 tRNA dihydrouridine synthase activity
The following genes encode enzymes with tRNA dihydrouridine synthase activity or are directly involved in the modification pathway across species.
| Gene | Major Role | Research Relevance |
|---|---|---|
| DusA (bacteria) | Introduces dihydrouridine at specific positions in tRNA | Model for studying bacterial translation and antibiotic targets |
| DusB (bacteria) | tRNA dihydrouridine synthase with distinct substrate specificity | Role in tRNA modification and stress response |
| DusC (bacteria) | tRNA dihydrouridine synthase | Potential target for antibacterial development |
| DUS1 (human) | Human tRNA dihydrouridine synthase | Implicated in mitochondrial tRNA modification |
| DUS2 (human) | Human tRNA dihydrouridine synthase | Overexpressed in lung cancer; interacts with PKR |
| DUS3 (human) | Human tRNA dihydrouridine synthase | Role in tRNA modification and translation |
| DUS4 (human) | Human tRNA dihydrouridine synthase | Potential role in mitochondrial function |
| Dus (T. thermophilus) | Thermophilic tRNA dihydrouridine synthase | Biochemical model for thermostability and catalysis |
| Dus1 (yeast) | Yeast tRNA dihydrouridine synthase | Genetic model for tRNA modification |
| Dus2 (yeast) | Yeast tRNA dihydrouridine synthase | Studies on tRNA modification and stress |
| Dus3 (yeast) | Yeast tRNA dihydrouridine synthase | Role in tRNA stability |
| Dus4 (yeast) | Yeast tRNA dihydrouridine synthase | Mitochondrial tRNA modification |
| PKR (human) | Interferon-induced protein kinase | Interacts with DUS2, linking tRNA modification to innate immunity |
| FMN1 (human) | Flavin mononucleotide cofactor biosynthesis | Provides FMN for Dus enzymes |
| NAD(P)H (metabolite) | Reducing agent for the reaction | Cofactor supply affects dihydrouridylation |
| tRNA (substrate) | Substrate for modification | Specific tRNA species are targeted by Dus enzymes |
How Is tRNA dihydrouridine synthase activity Regulated?
The activity of tRNA dihydrouridine synthases is regulated at multiple levels. The redox state of the cell directly influences enzyme activity, as the catalytic cycle involves NAD(P)H and FMN, and oxidative stress can modulate dihydrouridylation levels. In humans, DUS2 expression is induced by interferon and interacts with PKR, suggesting regulation by immune signaling pathways. Additionally, the availability of cofactors such as FMN and NAD(P)H can affect enzyme function. In bacteria, DusA activity is optimized for translation under specific growth conditions, and its expression may be controlled by global regulators.
tRNA dihydrouridine synthase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| DUS2 | Lung cancer | Knockout and overexpression in lung cancer cell lines |
| DUS2 | Innate immunity / antiviral response | PKR interaction studies in interferon-treated cells |
| DusA | Bacterial infection | Bacterial knockout models for antibiotic testing |
| DUS1/DUS4 | Mitochondrial dysfunction | Mitochondrial tRNA modification assays in patient cells |
| Dus enzymes | Oxidative stress response | Redox-sensitive reporter systems and stress models |
Cancer
Human DUS2 is overexpressed in pulmonary carcinogenesis and is considered a novel human tRNA-dihydrouridine synthase involved in lung cancer. The enzyme's interaction with PKR further links it to cancer cell signaling and immune evasion. Elevated dihydrouridylation may support the high translational demand of cancer cells, making DUS2 a potential therapeutic target.
Oxidative stress and metabolic disorders
Dihydrouridylation is sensitive to oxidative stress, and dysregulation of this modification can impair tRNA function under stress conditions. This has implications for metabolic disorders and diseases associated with oxidative damage, such as neurodegeneration and mitochondrial diseases.
Infectious diseases
Bacterial Dus enzymes are essential for optimal translation and fitness, making them attractive targets for new antibiotics. Inhibiting DusA or other bacterial dihydrouridine synthases could disrupt protein synthesis in pathogens.
From tRNA dihydrouridine synthase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the catalytic mechanism of DUS2? | Recombinant DUS2 with point mutations in catalytic residues |
| How does DUS2 overexpression affect cancer cell growth? | DUS2 overexpression in lung cancer cell lines |
| What is the role of DusA in bacterial translation? | DusA knockout in E. coli or other bacteria |
| How does redox state regulate dihydrouridylation? | Cells treated with oxidizing agents and DUS activity assays |
| What is the impact of DUS2 on PKR signaling? | DUS2 knockout or knockdown in interferon-treated cells |
| How does dihydrouridylation affect tRNA structure? | In vitro transcribed tRNA with site-specific modification |
How to Study the tRNA dihydrouridine synthase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| HPLC/MS | Dihydrouridine levels in tRNA | Quantification of modification stoichiometry |
| In vitro activity assay | Enzyme kinetics and substrate specificity | Characterization of Dus enzymes |
| X-ray crystallography | Three-dimensional structure of enzyme-tRNA complex | Mechanistic studies |
| tRNA-seq | Global mapping of tRNA modifications | Identification of dihydrouridine sites |
| Ribo-seq | Translation efficiency and codon usage | Impact of modification on protein synthesis |
| CRISPR knockout | Loss-of-function phenotypes | Gene function in cells and organisms |
| Co-immunoprecipitation | Protein-protein interactions | DUS2-PKR interaction studies |
| Redox sensitivity assays | Activity under oxidative stress | Link to stress response |
Biochemical assays for dihydrouridine synthase activity
Enzymatic activity can be measured using in vitro reactions with purified enzyme, tRNA substrate, and NAD(P)H, followed by detection of dihydrouridine by HPLC or mass spectrometry. These assays allow determination of kinetic parameters and substrate specificity.
Structural biology
X-ray crystallography and cryo-EM can reveal the atomic details of Dus enzymes bound to tRNA and cofactors, providing insights into the catalytic mechanism and substrate recognition.
RNA modification profiling
Next-generation sequencing-based methods, such as tRNA-seq and modification-specific sequencing, can map dihydrouridine sites across the transcriptome and quantify changes under different conditions.
CRISPR-based functional studies
Knockout, knockdown, and point mutation models generated by CRISPR-Cas9 allow researchers to dissect the cellular roles of DUS genes in translation, stress response, and disease.
How CRISPR Can Be Used to Study GO:0017150 tRNA dihydrouridine synthase activity
Knockout
CRISPR-Cas9 knockout of DUS genes in cell lines or model organisms can reveal their essential roles in tRNA modification and translation. For example, DUS2 knockout in lung cancer cells can test its requirement for proliferation and tumorigenicity.
Point Mutation
Introducing point mutations in catalytic residues (e.g., the conserved cysteine) of DUS enzymes via CRISPR can dissect the enzymatic mechanism and separate catalytic activity from other functions.
Knock-in
Knock-in of tagged DUS alleles (e.g., FLAG or GFP) allows for localization, interaction, and biochemical studies in a physiological context. This can be combined with endogenous promoters to study regulation.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression of DUS2 can model the overexpression observed in cancers and study its impact on translation and drug resistance.
How EDITGENE Supports tRNA dihydrouridine synthase activity Research
Researchers studying tRNA dihydrouridine synthase activity-related genes often need to determine whether a candidate gene is causally involved in tRNA modification, translation, or disease. EDITGENE provides a comprehensive suite of CRISPR-based services to accelerate this research, from gene knockout to precise point mutations and library screening.
Contact EDITGENE today to design your custom CRISPR model for tRNA dihydrouridine synthase activity research.
Frequently Asked Questions About tRNA dihydrouridine synthase activity
What is tRNA dihydrouridine synthase activity?
It is the enzymatic activity (GO:0017150) that converts uridine in tRNA to 5,6-dihydrouridine using NAD(P)H, a modification important for tRNA structure and translation.
What genes are involved in tRNA dihydrouridine synthase activity?
Key genes include DusA, DusB, DusC in bacteria and DUS1, DUS2, DUS3, DUS4 in humans, all encoding dihydrouridine synthase enzymes.
How does dihydrouridylation affect translation?
Dihydrouridine introduces flexibility into tRNA, which can influence codon-anticodon interactions and translation efficiency.
Is DUS2 linked to cancer?
Yes, DUS2 is overexpressed in lung cancer and is considered a novel human tRNA-dihydrouridine synthase involved in pulmonary carcinogenesis.
What is the role of DUS2 in immunity?
DUS2 interacts with the interferon-induced protein kinase PKR, linking tRNA modification to innate immune responses.
How is dihydrouridylation regulated by oxidative stress?
The activity of Dus enzymes is redox-sensitive, and oxidative stress can modulate dihydrouridine levels in tRNA.
What methods are used to study tRNA dihydrouridine synthase activity?
Common methods include in vitro enzyme assays, HPLC/MS, tRNA-seq, X-ray crystallography, and CRISPR-based functional studies.
Can CRISPR be used to study DUS genes?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect DUS gene function.
What diseases are associated with tRNA modification defects?
Dysregulation of tRNA modification has been linked to cancer, mitochondrial disorders, and neurodegenerative diseases.
Why is the Dus family conserved across species?
The conservation of Dus enzymes reflects the fundamental importance of dihydrouridylation for tRNA function and protein synthesis in all domains of life.
Conclusion
tRNA dihydrouridine synthase activity (GO:0017150) is a conserved molecular function that introduces a critical modification into tRNA, influencing translation and cellular stress responses. Its dysregulation is linked to cancer and other diseases, making it a promising target for therapeutic intervention. By combining biochemical, structural, and CRISPR-based approaches, researchers can uncover the detailed mechanisms and disease relevance of this important enzyme family.
References
- 1. Kilz LM et al.. 2024. Differential redox sensitivity of tRNA dihydrouridylation.. Nucleic Acids Res 52(21):12784-12797 PMID: 39460624
- 2. Kusuba H et al.. 2015. In vitro dihydrouridine formation by tRNA dihydrouridine synthase from Thermus thermophilus, an extreme-thermophilic eubacterium.. J Biochem 158(6):513-21 PMID: 26112661
- 3. Kato T et al.. 2005. A novel human tRNA-dihydrouridine synthase involved in pulmonary carcinogenesis.. Cancer Res 65(13):5638-46 PMID: 15994936
- 4. Bishop AC et al.. 2002. Identification of the tRNA-dihydrouridine synthase family.. J Biol Chem 277(28):25090-5 PMID: 11983710
- 5. Savage DF et al.. 2006. Molecular determinants of dihydrouridine synthase activity.. FEBS Lett 580(22):5198-202 PMID: 16962594
- 6. Schultz SK et al.. 2026. The tRNA dihydrouridine synthase DusA has a distinct mechanism in optimizing tRNAs for translation.. Nucleic Acids Res 54(8) PMID: 42080256
- 7. Mittelstadt M et al.. 2008. Interaction of human tRNA-dihydrouridine synthase-2 with interferon-induced protein kinase PKR.. Nucleic Acids Res 36(3):998-1008 PMID: 18096616
- 8. Fruchard L et al.. 2025. Beyond RNA modification: a novel role for tRNA modifying enzyme in oxidative stress response and metabolism.. Nucleic Acids Res 53(22) PMID: 41385321
