GO:0102267 tRNA-dihydrouridine20b synthase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0102267 describes the molecular function of catalyzing the NAD(P)-dependent conversion of a uracil20b in tRNA to a 5,6-dihydrouracil20b, producing NAD(P)H and H+.
• This activity belongs to the dihydrouridine synthase (DUS) family, which introduces dihydrouridine (D) modifications into tRNA.
• Dihydrouridine modification influences tRNA structure, stability, and translational fidelity, impacting protein synthesis.
• Dysregulation of tRNA modifications, including dihydrouridine, has been linked to cancer, neurological disorders, and mitochondrial diseases.
• Studying GO:0102267 requires integrating biochemical assays, structural biology, and CRISPR-based gene editing to dissect its cellular roles.
• EDITGENE provides comprehensive CRISPR services, including knockout, point mutation, knock-in, overexpression, and library screening, to accelerate research on tRNA-dihydrouridine20b synthase activity.
Description
The post-transcriptional modification of tRNA is essential for proper folding, stability, and decoding during translation. Among the numerous modifications, dihydrouridine (D) is one of the most abundant and is found in the D-loop of tRNAs from all domains of life. The enzyme responsible for this modification, tRNA-dihydrouridine synthase, catalyzes the reduction of uridine to dihydrouridine using NAD(P)H as a cofactor. The Gene Ontology term GO:0102267 specifically describes the activity of tRNA-dihydrouridine20b synthase, which acts on a uracil at position 20b of tRNA. This activity is critical for maintaining the structural integrity of tRNA and ensuring efficient protein synthesis. Researchers studying tRNA biology, translation, and related diseases are increasingly focusing on the enzymes that install these modifications, as their dysregulation can lead to a variety of pathological conditions. Understanding the molecular details of GO:0102267 is therefore fundamental for both basic and translational research.
tRNA-dihydrouridine20b synthase activity At A Glance
| GO ID | GO:0102267 |
|---|---|
| GO term | tRNA-dihydrouridine20b synthase activity |
| Ontology | molecular_function |
| Synonym | None |
| Definition | Catalysis of the reaction: a 5,6-dihydrouracil20b in tRNA + NAD(P) = H+ + a uracil20b in tRNA + NAD(P)H. |
| Major function | Introduces dihydrouridine modification at position 20b in tRNA |
| Cofactor | NAD(P)H |
| Substrate | Uracil20b in tRNA |
| Product | 5,6-dihydrouracil20b in tRNA |
What Is GO:0102267?
GO:0102267, tRNA-dihydrouridine20b synthase activity, is a molecular function defined as the catalysis of the reaction: a 5,6-dihydrouracil20b in tRNA + NAD(P) = H+ + a uracil20b in tRNA + NAD(P)H. In simpler terms, this activity uses NAD(P)H to reduce a specific uridine residue (uracil20b) within a tRNA molecule to dihydrouridine (5,6-dihydrouracil20b), thereby introducing a dihydrouridine modification at that position. This reaction is reversible and involves the transfer of hydride from NAD(P)H to the uracil base.
Why Is tRNA-dihydrouridine20b synthase activity Important in Cell Biology?
The dihydrouridine modification installed by GO:0102267 is crucial for tRNA structure and function. Dihydrouridine is known to increase the conformational flexibility of tRNA, which can affect its interactions with ribosomes and translation factors. Proper tRNA modification is essential for accurate and efficient protein synthesis, and defects in this process have been associated with a range of human diseases, including cancer, neurodegeneration, and mitochondrial disorders. Therefore, understanding the regulation and function of tRNA-dihydrouridine20b synthase activity is of significant biomedical importance.
• Dihydrouridine modification enhances tRNA structural flexibility, impacting translation efficiency.
• GO:0102267 is part of the broader tRNA modification network that ensures translational fidelity.
• Altered tRNA modification patterns are observed in various cancers, suggesting a role in tumorigenesis.
• Mutations in tRNA modification enzymes can cause neurological disorders and mitochondrial diseases.
• Dihydrouridine levels change in response to cellular stress, linking modification to stress adaptation.
• The activity requires NAD(P)H, connecting tRNA modification to cellular redox and metabolic states.
• Studying GO:0102267 can reveal new targets for therapeutic intervention in diseases linked to translation dysregulation.
• CRISPR-based models enable precise dissection of the physiological roles of tRNA-dihydrouridine20b synthase.
What Happens During tRNA-dihydrouridine20b synthase activity?
Substrate Recognition and Binding
In simple terms: The enzyme first finds and grabs the specific tRNA it needs to modify.
The tRNA-dihydrouridine20b synthase specifically recognizes its substrate tRNA through interactions with the tRNA's overall structure and specific sequence elements. It binds to the tRNA molecule and positions the target uracil20b residue into its active site for catalysis.
Hydride Transfer from NAD(P)H
In simple terms: The enzyme uses a helper molecule to donate a hydride to the uracil, starting the modification.
Once the substrate is bound, the enzyme facilitates the transfer of a hydride ion from the reduced cofactor NAD(P)H to the C5-C6 double bond of the uracil base. This step is the key reduction event that converts uracil to dihydrouracil.
Product Formation and Release
In simple terms: After the modification, the enzyme releases the modified tRNA and the used cofactor.
Following hydride transfer, the product 5,6-dihydrouracil20b is formed, and the oxidized cofactor NAD(P)+ is released. The modified tRNA is then released from the enzyme, ready to participate in translation.
Role in tRNA Structure and Function
In simple terms: The added modification helps the tRNA do its job better.
The dihydrouridine modification introduced by this activity increases the local flexibility of the tRNA, which can influence its folding and interactions with other molecules. This structural change is important for optimal tRNA function during protein synthesis.
Key Genes Involved in GO:0102267 tRNA-dihydrouridine20b synthase activity
The following genes encode proteins that either directly catalyze tRNA-dihydrouridine20b synthase activity or are closely associated with its function and regulation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| DUS1 | Catalyzes dihydrouridine formation at position 20b in tRNA | Model for studying tRNA modification and translation |
| DUS2 | Catalyzes dihydrouridine formation at position 20b in tRNA | Linked to cancer and mitochondrial function |
| DUS3 | Catalyzes dihydrouridine formation at position 20b in tRNA | Potential role in neurological disorders |
| DUS4 | Catalyzes dihydrouridine formation at position 20b in tRNA | Involved in stress response |
| tRNA | Substrate for modification | Central to translation and gene expression |
| NAD(P)H | Cofactor for reduction | Connects modification to cellular metabolism |
| NAD(P)+ | Oxidized cofactor product | Indicator of enzymatic activity |
| Dihydrouridine | Modified nucleotide product | Affects tRNA structure and stability |
| Uracil20b | Target nucleotide in tRNA | Specificity determinant for the enzyme |
| 5,6-dihydrouracil20b | Modified nucleotide product | Marker of successful modification |
| Translation machinery | Downstream effector of tRNA modification | Impacts protein synthesis fidelity |
| Ribosome | Interacts with modified tRNA | Site of translation |
| Aminoacyl-tRNA synthetase | Charges tRNA with amino acids | Coupled to tRNA modification status |
| Elongation factors | Facilitate tRNA movement during translation | Sensitive to tRNA structure |
| Stress response pathways | Regulate tRNA modification enzymes | Link modification to cellular stress |
| Metabolic enzymes | Provide NAD(P)H | Supply cofactor for the reaction |
| Mitochondrial proteins | May interact with DUS enzymes | Implicated in mitochondrial diseases |
How Is tRNA-dihydrouridine20b synthase activity Regulated?
The activity of tRNA-dihydrouridine20b synthase is regulated at multiple levels. Expression of the DUS genes can be induced under certain stress conditions, such as oxidative stress or nutrient limitation, to modulate translation. Additionally, the availability of the cofactor NAD(P)H, which is tied to cellular metabolic status, can influence the reaction rate. Post-translational modifications of the enzyme may also affect its activity or localization. However, the precise regulatory mechanisms remain an active area of research.
tRNA-dihydrouridine20b synthase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| DUS2 | Cancer, mitochondrial dysfunction | Knockout cancer cell lines, xenograft models |
| DUS3 | Neurological disorders | Neuronal knockout models, iPSC-derived neurons |
| DUS1 | Translation-related diseases | CRISPR knockout in HEK293T, ribosome profiling |
| DUS4 | Stress response, metabolic disorders | Overexpression and knockout in stress models |
| tRNA | Broad impact on translation | Mutant tRNA knock-in models |
Cancer
Alterations in tRNA modification enzymes, including dihydrouridine synthases, have been observed in various cancers. Changes in dihydrouridine levels can affect the translation of oncogenes or tumor suppressors, contributing to cancer progression. Targeting these enzymes is being explored as a potential therapeutic strategy.
Neurological Disorders
Defects in tRNA modifications are linked to neurological disorders such as intellectual disability and neurodegeneration. Mutations in genes involved in dihydrouridine synthesis may lead to impaired translation in neurons, which are particularly sensitive to translational defects.
Mitochondrial Diseases
Mitochondrial tRNAs also undergo dihydrouridine modification. Dysfunction of the modifying enzymes can impair mitochondrial translation, leading to mitochondrial diseases characterized by energy metabolism defects.
From tRNA-dihydrouridine20b synthase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the effect of DUS2 knockout on cancer cell proliferation? | DUS2 knockout in cancer cell lines (e.g., HeLa, MCF7) |
| How does a point mutation in the catalytic site of DUS3 affect tRNA modification? | Point mutation knock-in in DUS3 using CRISPR |
| Does overexpression of DUS1 enhance translation under stress? | DUS1 overexpression cell lines |
| What is the interactome of DUS4? | Tagged knock-in of DUS4 (e.g., FLAG, HA) followed by mass spectrometry |
| How does loss of DUS2 affect mitochondrial function? | DUS2 knockout in mitochondrial reporter cells |
| Can CRISPR library screening identify synthetic lethal partners of DUS3? | Genome-wide CRISPR knockout library in DUS3-mutant cells |
How to Study the tRNA-dihydrouridine20b synthase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| In vitro enzyme assay | Catalytic activity of DUS enzymes | Kinetic studies, inhibitor screening |
| LC-MS/MS | Dihydrouridine levels in tRNA | Quantification of modification changes |
| Ribo-seq | Translation efficiency and codon usage | Impact of modification on protein synthesis |
| CRISPR knockout | Loss-of-function phenotypes | Gene function studies |
| CRISPR knock-in | Tagged or mutant protein expression | Localization, interaction studies |
| RNA immunoprecipitation | Enzyme-tRNA interactions | Mapping binding sites |
| Cryo-EM | 3D structure of enzyme-tRNA complex | Mechanistic insights |
Biochemical Assays for Enzyme Activity
Direct measurement of tRNA-dihydrouridine20b synthase activity can be performed using in vitro assays with purified enzyme, tRNA substrate, and NAD(P)H. The formation of dihydrouridine can be detected by HPLC or mass spectrometry.
RNA Modification Profiling
Global analysis of tRNA modifications, including dihydrouridine, can be achieved using techniques such as RNA-seq with modification-specific antibodies or direct RNA sequencing. These methods allow mapping of modification sites and quantification of changes.
CRISPR-Based Genetic Screens
Genome-wide CRISPR knockout or activation screens can identify genes that modulate the function of tRNA-dihydrouridine20b synthase or that are synthetically lethal with its loss. Such screens are powerful for uncovering pathways connected to tRNA modification.
Structural Biology
X-ray crystallography and cryo-EM can provide detailed structural insights into how the enzyme binds tRNA and catalyzes the reduction reaction. These studies inform on mechanism and aid inhibitor design.
How CRISPR Can Be Used to Study GO:0102267 tRNA-dihydrouridine20b synthase activity
Knockout
CRISPR knockout of DUS genes can abolish tRNA-dihydrouridine20b synthase activity, allowing researchers to study the consequences of losing this modification on tRNA stability, translation, and cellular phenotypes. Knockout cell lines are valuable for identifying synthetic lethal interactions and validating drug targets.
Point Mutation
Introducing specific point mutations into the catalytic domain of DUS enzymes via CRISPR can help dissect the enzymatic mechanism and separate catalytic activity from other functions. Such models are useful for understanding how disease-associated mutations affect activity.
Knock-in
Knock-in of tagged versions of DUS proteins (e.g., GFP, FLAG) enables visualization and purification of the enzyme for interaction studies. Knock-in of disease-relevant mutations can create isogenic models to study pathogenesis.
Overexpression
CRISPR activation (CRISPRa) or traditional overexpression can increase DUS enzyme levels, allowing study of gain-of-function effects and the impact of elevated dihydrouridine modification on translation and cell physiology.
How EDITGENE Supports tRNA-dihydrouridine20b synthase activity Research
Researchers studying tRNA-dihydrouridine20b synthase activity-related genes often need to determine whether a candidate gene is causally involved in a specific cellular process or disease. EDITGENE provides a comprehensive suite of CRISPR-based services to enable precise genetic manipulation and functional interrogation of these genes.
Contact EDITGENE today to design your custom CRISPR model for tRNA-dihydrouridine20b synthase activity research.
Frequently Asked Questions About tRNA-dihydrouridine20b synthase activity
What is GO:0102267?
GO:0102267 is the Gene Ontology term for tRNA-dihydrouridine20b synthase activity, which catalyzes the NAD(P)H-dependent reduction of uracil20b in tRNA to 5,6-dihydrouracil20b.
What genes are involved in tRNA-dihydrouridine20b synthase activity?
Genes encoding dihydrouridine synthase (DUS) family enzymes, such as DUS1, DUS2, DUS3, and DUS4, are involved in this activity.
What is the function of tRNA-dihydrouridine20b synthase?
It introduces a dihydrouridine modification at position 20b of tRNA, which affects tRNA structure and translation efficiency.
Which diseases are associated with tRNA-dihydrouridine20b synthase activity?
Dysregulation of this activity has been linked to cancer, neurological disorders, and mitochondrial diseases.
How can I study tRNA-dihydrouridine20b synthase activity?
You can study it using biochemical assays, RNA modification profiling, CRISPR knockout/knock-in models, and structural biology techniques.
What cofactors are required for tRNA-dihydrouridine20b synthase activity?
The reaction requires NAD(P)H as a hydride donor.
What is the substrate of tRNA-dihydrouridine20b synthase?
The substrate is a uracil20b residue within a tRNA molecule.
What is the product of the reaction catalyzed by GO:0102267?
The product is a 5,6-dihydrouracil20b in tRNA, along with NAD(P)+ and H+.
Can CRISPR be used to study tRNA-dihydrouridine20b synthase?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models can be used to dissect the function of DUS genes.
What services does EDITGENE offer for tRNA modification research?
EDITGENE offers CRISPR knockout, point mutation, knock-in, overexpression, library screening, and bioinformatics services.
Conclusion
GO:0102267, tRNA-dihydrouridine20b synthase activity, represents a critical enzymatic function in tRNA modification that impacts translation and cellular physiology. Its dysregulation is implicated in various human diseases, making it an important target for basic and translational research. By leveraging advanced CRISPR technologies and EDITGENE's comprehensive services, researchers can uncover the detailed mechanisms and therapeutic potential of this activity.
References
- 1. Sun S et al.. 2025. Exercise-induced histone lactylation in monocyte-derived macrophages restores cardiac immune homeostasis and function in sepsis-induced cardiomyopathy.. Nat Commun 17(1):756 PMID: 41398160
