GO:0106143 tRNA (m7G46) methyltransferase complex: Components, Assembly and Research Methods, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0106143 describes the tRNA (m7G46) methyltransferase complex, a cellular component that catalyzes formation of 7-methylguanine at position 46 in certain tRNAs such as tRNA(Phe) and tRNA(Met).
• In yeast, the complex is a heterotetramer of two subunits: Trm8 (catalytic) and Trm82 (WD repeat).
• The catalytic subunit adopts a Rossmann-fold methyltransferase domain, while the WD-repeat subunit is required for stability and tRNA binding.
• Structural and biochemical studies show that the complex recognizes the tRNA elbow region and flips the target guanine into the active site for S-adenosylmethionine-dependent methylation.
• Loss of m7G46 methylation destabilizes tRNA and impairs translation, linking the complex to growth control and disease.
• The complex can be produced in cell-free systems and studied by structural biology, RNA modification mapping, and CRISPR-based models.
Description
GO:0106143, the tRNA (m7G46) methyltransferase complex, is a cellular component defined by its role in catalyzing the formation of 7-methylguanine at position 46 of certain tRNAs, including tRNA(Phe) and tRNA(Met). This modification is introduced post-transcriptionally and is conserved from bacteria to humans, where the homologous METTL1-WDR4 complex performs the same reaction. The complex is best characterized in yeast as a heterotetramer of Trm8 and Trm82, but structural and biochemical work has revealed a common architecture and catalytic strategy across species. Researchers study this complex because m7G46 is a key structural determinant of the tRNA elbow, and its loss affects tRNA stability, translation efficiency, and cellular growth. The complex therefore sits at the intersection of RNA modification, translation control, and disease mechanisms, making it a relevant target for functional genomics and therapeutic exploration.
tRNA (m7G46) methyltransferase complex At A Glance
| GO ID | GO:0106143 |
|---|---|
| GO term | tRNA (m7G46) methyltransferase complex |
| Ontology | cellular_component |
| Synonym | Trm8-Trm82 complex; tRNA (m7G46) methyltransferase; tRNA m7G methylation complex |
| Major function | Catalysis of 7-methylguanine formation at position 46 in certain tRNAs |
| Subunit composition | Heterotetramer of catalytic Trm8 and WD-repeat Trm82 in yeast; homologous METTL1-WDR4 in humans |
| Substrate | tRNA(Phe), tRNA(Met), and other tRNAs with a G46 in the elbow region |
| Cofactor | S-adenosylmethionine (SAM) as methyl donor |
| Conservation | Found in bacteria (TrmB), yeast (Trm8-Trm82), and humans (METTL1-WDR4) |
What Is GO:0106143?
The tRNA (m7G46) methyltransferase complex is a protein assembly that catalyzes the methylation of guanine at position 46 in specific tRNAs, producing 7-methylguanine (m7G46). In yeast, it is a heterotetramer composed of two catalytic Trm8 subunits and two WD-repeat Trm82 subunits. The complex uses S-adenosylmethionine as the methyl donor and recognizes tRNA substrates through a combination of catalytic and auxiliary subunit interactions.
Why Is tRNA (m7G46) methyltransferase complex Important in Cell Biology?
The tRNA (m7G46) methyltransferase complex is important because m7G46 is a conserved tRNA modification that stabilizes the tRNA elbow and supports efficient translation. Disruption of the complex reduces m7G46 levels, destabilizes tRNA, and impairs growth, which has been linked to cancer and other diseases. Understanding its structure and mechanism provides a basis for targeting RNA modification pathways in disease and for interpreting genetic variants in the catalytic and auxiliary subunits.
• m7G46 is a conserved tRNA modification that stabilizes tRNA structure and supports translation.
• The complex is required for normal growth in yeast and likely in higher organisms.
• Human METTL1-WDR4 is the homolog of the yeast complex and is implicated in cancer.
• Structural studies reveal a conserved Rossmann-fold methyltransferase domain and a WD-repeat scaffold.
• The complex recognizes the tRNA elbow and flips the target guanine into the active site.
• Loss of m7G46 affects tRNA stability and can trigger stress responses.
• The complex can be produced in cell-free systems for biochemical and structural studies.
• It is a model system for understanding RNA modification enzyme assembly and substrate recognition.
• Mutations in subunits may contribute to ribosomopathies or translation-related disorders.
• The complex is a potential target for RNA modification-based therapeutics.
Structure and Composition of tRNA (m7G46) methyltransferase complex
Catalytic subunit Trm8/METTL1
In simple terms: The catalytic subunit is the part that actually performs the methylation reaction.
Trm8 in yeast and METTL1 in humans contain a Rossmann-fold methyltransferase domain that binds S-adenosylmethionine and catalyzes methyl transfer to guanine 46. Structural studies show a conserved active site that accommodates the flipped guanine base.
Auxiliary subunit Trm82/WDR4
In simple terms: The auxiliary subunit helps the catalytic subunit fold, bind tRNA, and stay stable.
Trm82 in yeast and WDR4 in humans are WD-repeat proteins that form a beta-propeller scaffold. They are required for stability and activity of the catalytic subunit and contribute to tRNA binding.
Heterotetramer assembly
In simple terms: The complex is built from two copies of each subunit, forming a four-part machine.
In yeast, the complex is a heterotetramer of two Trm8 and two Trm82 subunits. Cell-free translation studies have shown that co-expression of both subunits is needed for a functional complex.
tRNA recognition interface
In simple terms: The complex grabs the tRNA at its elbow and positions the target base for modification.
The complex recognizes the tRNA elbow region, and the target guanine at position 46 is flipped into the active site. This mechanism is conserved from bacterial TrmB to eukaryotic Trm8-Trm82 and human METTL1-WDR4.
Key Genes Involved in GO:0106143 tRNA (m7G46) methyltransferase complex
The following genes and proteins are the core components and related factors of the tRNA (m7G46) methyltransferase complex across model organisms.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TRM8 (yeast) | Catalytic subunit with Rossmann-fold methyltransferase domain | Model for catalytic mechanism and substrate recognition |
| TRM82 (yeast) | WD-repeat auxiliary subunit required for stability and tRNA binding | Model for subunit assembly and regulation |
| METTL1 (human) | Catalytic subunit homolog of Trm8 | Implicated in cancer and tRNA modification |
| WDR4 (human) | WD-repeat auxiliary subunit homolog of Trm82 | Mutations linked to tRNA modification defects |
| TrmB (Bacillus subtilis) | Bacterial homolog with a single subunit | Structural model for the catalytic core |
| tRNA(Phe) | Substrate tRNA with G46 in the elbow | Model substrate for methylation assays |
| tRNA(Met) | Substrate tRNA with G46 in the elbow | Model substrate for methylation assays |
| SAM (cofactor) | Methyl donor for the reaction | Biochemical assays and inhibitor design |
| TRDMT1/DNMT2 | Related tRNA methyltransferase in moss | Comparative RNA modification studies |
| Wheat germ cell-free system | Expression platform for complex production | Biochemical and structural studies |
| Trm8-Trm82 complex | Heterotetrameric enzyme | Core research object for GO:0106143 |
| METTL1-WDR4 complex | Human heterodimeric enzyme | Disease-related research |
| m7G46 modification | Product of the reaction | Readout for complex activity |
| tRNA elbow | Structural region recognized by the complex | Substrate recognition studies |
| Rossmann-fold domain | Catalytic domain of Trm8/METTL1 | Mechanistic and structural studies |
| WD-repeat domain | Scaffold domain of Trm82/WDR4 | Assembly and interaction studies |
How Is tRNA (m7G46) methyltransferase complex Regulated?
The tRNA (m7G46) methyltransferase complex is regulated at multiple levels. Its activity depends on the availability of S-adenosylmethionine and on the expression and assembly of both subunits. In yeast, co-expression of Trm8 and Trm82 is required for a functional complex, indicating that subunit stoichiometry is a regulatory point. In humans, METTL1-WDR4 activity can be influenced by cellular growth signals and stress, although the precise upstream regulators are still being defined. tRNA substrate availability and structural features also modulate methylation efficiency.
tRNA (m7G46) methyltransferase complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| METTL1 | Cancer, translation control | Knockout and overexpression in cancer cell lines |
| WDR4 | tRNA modification defects, developmental phenotypes | Point mutation knock-in in cell lines |
| TRM8 | Growth defects in yeast | Yeast knockout and rescue |
| TRM82 | Growth defects in yeast | Yeast knockout and rescue |
| TRDMT1/DNMT2 | RNA modification network in moss | Comparative knockout in Physcomitrium patens |
Cancer
Human METTL1-WDR4, the homolog of the yeast tRNA (m7G46) methyltransferase complex, has been implicated in cancer through its role in tRNA modification and translation control. Altered m7G46 levels can affect the translation of oncogenic transcripts and contribute to tumor growth.
Ribosomopathies and translation disorders
Because m7G46 stabilizes tRNA and supports translation, defects in the complex could contribute to ribosomopathies or other translation-related disorders. Loss of m7G46 reduces tRNA stability and can impair protein synthesis.
Neurological and developmental conditions
tRNA modification defects, including those affecting m7G46, have been linked to neurological and developmental phenotypes in model systems, although direct evidence for the complex in human disease is still emerging.
From tRNA (m7G46) methyltransferase complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the catalytic mechanism of m7G46 formation? | Recombinant Trm8-Trm82 or METTL1-WDR4 with tRNA substrates |
| How does the complex assemble? | Cell-free translation of subunits and co-expression |
| What is the role of m7G46 in translation? | Yeast knockout and polysome profiling |
| How do disease variants affect activity? | Point mutation knock-in in human cell lines |
| What genes regulate the complex? | CRISPR knockout library screening |
| How does loss of the complex affect tRNA stability? | RNA-seq and tRNA modification mapping |
How to Study the tRNA (m7G46) methyltransferase complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| X-ray crystallography | Three-dimensional structure | Active site and tRNA recognition |
| Cryo-EM | Structure of large complexes | METTL1-WDR4-tRNA complex |
| Methyltransferase assay | Enzymatic activity | Kinetics and inhibitor testing |
| Mass spectrometry | RNA modification levels | Quantification of m7G46 |
| RNA-seq | Transcript abundance and modification | tRNA stability and translation |
| Polysome profiling | Translation efficiency | Effect of complex loss |
| Cell-free translation | Protein complex production | Recombinant enzyme for assays |
Structural biology
X-ray crystallography and cryo-EM have been used to determine structures of TrmB, Trm8-Trm82, and METTL1-WDR4 in complex with tRNA, revealing the catalytic mechanism and substrate recognition.
Biochemical assays
Methyltransferase activity can be measured using radioactive SAM or mass spectrometry to detect m7G46 formation on tRNA substrates.
Cell-free expression
Wheat germ cell-free translation systems have been used to produce the yeast Trm8-Trm82 complex for biochemical and structural studies.
RNA modification mapping
RNA-seq and specialized tRNA modification mapping methods can quantify m7G46 levels and assess the impact of complex loss or mutation.
How CRISPR Can Be Used to Study GO:0106143 tRNA (m7G46) methyltransferase complex
Knockout
CRISPR knockout of METTL1 or WDR4 can abolish m7G46 formation, leading to tRNA destabilization and growth defects, providing a clean loss-of-function model.
Point Mutation
Point mutation knock-in of catalytic residues or disease-associated variants can dissect the mechanism and assess pathogenicity.
Knock-in
Tagged knock-in of endogenous METTL1 or WDR4 allows localization and interaction studies in a physiological context.
Overexpression
Overexpression of the complex can test gain-of-function effects on translation and cell growth, particularly in cancer models.
How EDITGENE Supports tRNA (m7G46) methyltransferase complex Research
Researchers studying tRNA (m7G46) methyltransferase complex-related genes often need to determine whether a candidate gene is causally involved in tRNA modification, translation control, or disease. EDITGENE provides CRISPR-based cell models and screening services to enable these functional studies.
Contact EDITGENE today to design your custom CRISPR model for tRNA (m7G46) methyltransferase complex research.
Frequently Asked Questions About tRNA (m7G46) methyltransferase complex
What is GO:0106143?
GO:0106143 is the Gene Ontology term for the tRNA (m7G46) methyltransferase complex, a protein complex that catalyzes formation of 7-methylguanine at position 46 in certain tRNAs.
What genes are involved in the tRNA (m7G46) methyltransferase complex?
In yeast, the complex is composed of TRM8 (catalytic) and TRM82 (WD repeat); in humans, the homologs are METTL1 and WDR4.
What does the tRNA (m7G46) methyltransferase complex do?
It adds a methyl group to guanine 46 of specific tRNAs using S-adenosylmethionine, producing m7G46 and stabilizing tRNA structure.
Where is the tRNA (m7G46) methyltransferase complex found?
It is found in bacteria (TrmB), yeast (Trm8-Trm82), and humans (METTL1-WDR4), and is conserved across species.
How is the tRNA (m7G46) methyltransferase complex structured?
In yeast it is a heterotetramer of two Trm8 and two Trm82 subunits; the catalytic subunit has a Rossmann-fold domain and the auxiliary subunit is a WD-repeat protein.
What diseases are linked to the tRNA (m7G46) methyltransferase complex?
Human METTL1-WDR4 has been implicated in cancer and translation-related disorders, though direct disease links are still being defined.
How can I study the tRNA (m7G46) methyltransferase complex?
Common methods include structural biology, methyltransferase assays, RNA modification mapping, and CRISPR knockout models.
What is m7G46?
m7G46 is 7-methylguanine at position 46 of certain tRNAs, a conserved modification introduced by the tRNA (m7G46) methyltransferase complex.
Is the tRNA (m7G46) methyltransferase complex conserved in humans?
Yes, the human METTL1-WDR4 complex is the homolog of the yeast Trm8-Trm82 complex and performs the same reaction.
What CRISPR models are available for this complex?
Knockout, point mutation, knock-in, tagged knock-in, and overexpression models can be generated for METTL1, WDR4, and related genes.
Conclusion
The tRNA (m7G46) methyltransferase complex (GO:0106143) is a conserved cellular component that introduces the m7G46 modification in tRNA, stabilizing tRNA structure and supporting translation. Its study spans structural biology, biochemistry, and functional genomics, with growing relevance to cancer and translation-related diseases. CRISPR-based models and screening approaches provide powerful tools to dissect its mechanism and disease connections.
References
- 1. Blersch KF et al.. 2021. Structural model of the M7G46 Methyltransferase TrmB in complex with tRNA.. RNA Biol 18(12):2466-2479 PMID: 34006170
- 2. Ruiz-Arroyo VM et al.. 2023. Structures and mechanisms of tRNA methylation by METTL1-WDR4.. Nature 613(7943):383-390 PMID: 36599982
- 3. Matsumoto K et al.. 2007. RNA recognition mechanism of eukaryote tRNA (m7G46) methyltransferase (Trm8-Trm82 complex).. FEBS Lett 581(8):1599-604 PMID: 17382321
- 4. Zegers I et al.. 2006. Crystal structure of Bacillus subtilis TrmB, the tRNA (m7G46) methyltransferase.. Nucleic Acids Res 34(6):1925-34 PMID: 16600901
- 5. Muneyoshi Y et al.. 2007. Hetero subunit interaction and RNA recognition of yeast tRNA (m7G46) methyltransferase synthesized in a wheat germ cell-free translation system.. Nucleic Acids Symp Ser (Oxf) PMID: 18029735
- 6. Kanojia Y et al.. 2026. tRNA methyltransferase (TRDMT1/DNMT2) participates in network of RNA modification in the Moss Physcomitrium patens.. Biochim Biophys Acta Proteins Proteom 1874(6):141165 PMID: 42546863
- 7. Matsumoto K et al.. 2008. Production of yeast tRNA (m(7)G46) methyltransferase (Trm8-Trm82 complex) in a wheat germ cell-free translation system.. J Biotechnol 133(4):453-60 PMID: 18164779
- 8. Hori H. 2010. Synthesis of a hetero subunit RNA modification enzyme by the wheat germ cell-free translation system.. Methods Mol Biol 607:173-85 PMID: 20204857
