{"gene":"TRMT1L","run_date":"2026-06-10T10:51:56","timeline":{"discoveries":[{"year":2021,"finding":"TRMT1L is responsible for methylating a subset of cytosolic tRNAAla(AGC) isodecoders at position 26, producing the N2,N2-dimethylguanosine (m2,2G) modification; prior to this work, TRMT1L's enzymatic activity was unknown.","method":"Next-generation sequencing, LC-MS/MS, patient-derived cell lines, and knockout mouse models","journal":"RNA biology","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — multiple orthogonal methods (sequencing, mass spectrometry, KO models) in a single study directly demonstrating enzymatic activity","pmids":["33499731"],"is_preprint":false},{"year":2021,"finding":"Upon neuronal activation (mimicking long-term potentiation) in vitro, TRMT1L undergoes subcellular relocalization from nucleoli to small punctate compartments in the nucleus; this relocalization does not occur upon heat shock, indicating it is specific to neuronal activation rather than a general stress response.","method":"Cellular in vitro neuronal activation model, subcellular localization imaging (fluorescence microscopy), heat-shock control experiments","journal":"RNA biology","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — direct localization experiment with functional context, single lab, two orthogonal stimuli tested as controls","pmids":["33499731"],"is_preprint":false},{"year":2025,"finding":"TRMT1L is the enzyme catalyzing m2,2G at position 27 of tyrosine tRNAs (tRNA-Tyr), a modification distinct from TRMT1's activity at position 26; additionally, TRMT1L is required for maintaining 3-(3-amino-3-carboxypropyl)uridine (acp3U) modifications in a subset of tRNAs through a process that can be uncoupled from its methyltransferase activity.","method":"Comprehensive tRNA sequencing (tRNA-seq), LC-MS/MS, TRMT1L knockout cell lines","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — replicated independently across two labs (PMID 39786990 and 39786998) using multiple orthogonal sequencing and mass spectrometry methods","pmids":["39786990","39786998"],"is_preprint":false},{"year":2025,"finding":"TRMT1L depletion impairs deposition of acp3U and dihydrouridine on tRNA-Tyr-GUA, tRNA-Cys-GCA, and tRNA-Ala-CGC, indicating TRMT1L participates in a tRNA modification circuit beyond its direct methyltransferase activity.","method":"eCLIP-seq, nanopore tRNA-seq, TRMT1L knockout/depletion cell lines","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — replicated in two independent studies using multiple orthogonal sequencing methods","pmids":["39786990","39786998","39416027"],"is_preprint":false},{"year":2025,"finding":"TRMT1L knockout cells exhibit decreased tRNA-Tyr-GUA levels, reduced global mRNA translation rates, and hypersensitivity to oxidative stress, establishing a functional link between TRMT1L-catalyzed m2,2G27 and translational regulation and cell survival under stress.","method":"TRMT1L knockout cell lines, global translation rate assays, oxidative stress viability assays","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean KO with defined cellular phenotypes (translation, stress survival), replicated across two independent studies","pmids":["39786998","39416027"],"is_preprint":false},{"year":2025,"finding":"TRMT1L interacts with a component of the Rix1 ribosome biogenesis complex and binds to 28S rRNA as well as a subset of tRNAs, as determined by eCLIP-seq.","method":"eCLIP-seq","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — eCLIP-seq identifies binding partners, single lab, no reciprocal validation reported in abstract","pmids":["39786998","39416027"],"is_preprint":false},{"year":2025,"finding":"Tyrosine and serine tRNAs are dependent upon m2,2G modifications for their stability and function in translation; human patient cells with disease-associated TRMT1 variants exhibit reduced levels of tyrosine and serine tRNAs.","method":"tRNA-seq in TRMT1L/TRMT1 knockout and patient-derived cell lines, translation functional assays","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO and patient-derived cells with direct tRNA quantification, single study","pmids":["39786990"],"is_preprint":false},{"year":2006,"finding":"Mouse Trm1-like (ortholog of human TRMT1L/C1orf25), when disrupted by gene-trap insertion in the first intron, causes significantly altered motor coordination and aberrant exploratory behaviour in viable mice, with expression detected in neural tissues including spinal ganglia, trigeminal nerve, olfactory epithelium, and brain nuclei during embryogenesis and in adult brain.","method":"Gene-trap mouse model, behavioral testing (motor coordination and exploratory behavior), LacZ reporter for expression mapping","journal":"Gene","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — clean loss-of-function model with defined behavioral phenotype and expression mapping, single lab","pmids":["17198746"],"is_preprint":false}],"current_model":"TRMT1L is a tRNA methyltransferase that specifically catalyzes N2,N2-dimethylguanosine (m2,2G) at position 27 of tyrosine tRNAs (and position 26 of a subset of tRNAAla isodecoders), and also facilitates deposition of acp3U and dihydrouridine modifications on select tRNAs through a process separable from its methyltransferase activity; loss of TRMT1L reduces tRNA-Tyr levels, globally impairs mRNA translation, and increases sensitivity to oxidative stress, while upon neuronal activation TRMT1L redistributes from nucleoli to nuclear puncta in a stimulus-specific manner, implicating it in neuronal plasticity."},"narrative":{"mechanistic_narrative":"TRMT1L is a tRNA methyltransferase that shapes the cytosolic tRNA modification landscape and, through it, global translation and stress resilience [PMID:39786990, PMID:39786998, PMID:39416027]. It catalyzes N2,N2-dimethylguanosine (m2,2G): at position 26 of a subset of tRNA-Ala(AGC) isodecoders [PMID:33499731] and, distinct from the related TRMT1 activity, at position 27 of tyrosine tRNAs [PMID:39786990, PMID:39786998]. Beyond direct methylation, TRMT1L is required for deposition of acp3U and dihyduridine on select tRNAs (tRNA-Tyr-GUA, tRNA-Cys-GCA, tRNA-Ala-CGC) through a circuit that can be uncoupled from its methyltransferase activity, placing it within a broader tRNA-modification network [PMID:39786990, PMID:39786998, PMID:39416027]. Loss of TRMT1L reduces tRNA-Tyr-GUA levels, lowers global mRNA translation rates, and renders cells hypersensitive to oxidative stress [PMID:39786998, PMID:39416027]. Consistent with a role in ribosome and tRNA biology, TRMT1L interacts with a component of the Rix1 ribosome biogenesis complex and binds 28S rRNA and a subset of tRNAs [PMID:39786998, PMID:39416027]. In neurons, TRMT1L relocalizes from nucleoli to nuclear puncta specifically upon neuronal activation but not heat shock [PMID:33499731], and disruption of its mouse ortholog produces altered motor coordination and exploratory behavior with expression in neural tissues [PMID:17198746], linking the enzyme to neuronal function.","teleology":[{"year":2006,"claim":"Before any molecular activity was known, loss-of-function in the mouse ortholog established that TRMT1L has a physiological role in the nervous system, framing it as a brain-relevant gene.","evidence":"Gene-trap mouse model with behavioral testing and LacZ expression mapping","pmids":["17198746"],"confidence":"Medium","gaps":["No molecular mechanism connecting the behavioral phenotype to a biochemical activity","Single lab","Gene-trap may not be a complete null"]},{"year":2021,"claim":"The first enzymatic assignment showed TRMT1L is an active m2,2G methyltransferase, resolving its long-unknown biochemical function.","evidence":"NGS, LC-MS/MS, patient-derived and knockout mouse cell lines identifying m2,2G at position 26 of tRNA-Ala(AGC) isodecoders","pmids":["33499731"],"confidence":"High","gaps":["Did not yet define the full substrate repertoire (tRNA-Tyr position 27 came later)","Functional consequence for translation not established in this work"]},{"year":2021,"claim":"Subcellular imaging linked the enzyme to neuronal plasticity by showing stimulus-specific relocalization, distinguishing it from a generic stress response.","evidence":"In vitro neuronal activation model with fluorescence microscopy and heat-shock control","pmids":["33499731"],"confidence":"Medium","gaps":["Identity and function of the nuclear puncta unknown","Mechanism coupling activation to relocalization not defined","Single lab"]},{"year":2025,"claim":"Independent studies defined tRNA-Tyr position 27 as the principal m2,2G target and revealed a methyltransferase-uncoupled role in acp3U/dihydrouridine deposition, expanding TRMT1L from a single-mark enzyme to a node in a tRNA modification circuit.","evidence":"tRNA-seq, nanopore tRNA-seq, eCLIP-seq and LC-MS/MS in knockout/depletion cell lines, replicated across labs","pmids":["39786990","39786998","39416027"],"confidence":"High","gaps":["Mechanism by which TRMT1L promotes acp3U/dihydrouridine independent of catalysis is unknown","Enzymes it cooperates with for those marks not identified"]},{"year":2025,"claim":"Phenotypic analysis tied the molecular activity to organism-level consequences: TRMT1L loss destabilizes tRNA-Tyr, depresses global translation, and sensitizes cells to oxidative stress.","evidence":"Knockout cell lines with global translation rate assays and oxidative stress viability assays","pmids":["39786998","39416027"],"confidence":"High","gaps":["Causal chain from m2,2G27 loss to oxidative stress sensitivity not mechanistically dissected","Codon-specific translational effects not mapped"]},{"year":2025,"claim":"Binding studies positioned TRMT1L within ribosome biogenesis machinery, suggesting its tRNA role intersects with rRNA/ribosome processing.","evidence":"eCLIP-seq showing interaction with a Rix1 complex component and binding to 28S rRNA and tRNAs","pmids":["39786998","39416027"],"confidence":"Medium","gaps":["No reciprocal validation of the Rix1 component interaction","Functional consequence of 28S rRNA binding unknown"]},{"year":null,"claim":"How TRMT1L mechanistically promotes acp3U and dihydrouridine without catalyzing them, and how its activation-dependent nuclear relocalization connects to translational control in neurons, remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["Non-catalytic mechanism for acp3U/DHU support undefined","Molecular link between neuronal relocalization and tRNA modification not established","No structural model of substrate recognition"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[0,2]},{"term_id":"GO:0140098","term_label":"catalytic activity, acting on RNA","supporting_discovery_ids":[0,2]},{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[5]}],"localization":[{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[1]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[1]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[0,2,3]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[4]}],"complexes":[],"partners":[],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q7Z2T5","full_name":"tRNA (guanine(27)-N(2))-dimethyltransferase","aliases":["tRNA methyltransferase 1-like protein","TRMT1-like protein"],"length_aa":733,"mass_kda":81.7,"function":"Specifically dimethylates a single guanine residue at position 27 of tRNA(Tyr) using S-adenosyl-L-methionine as donor of the methyl groups (PubMed:39786990, PubMed:39786998). Dimethylation at position 27 of tRNA(Tyr) is required for efficient translation of tyrosine codons (PubMed:39786990, PubMed:39786998). Also required to maintain 3-(3-amino-3-carboxypropyl)uridine (acp3U) in the D-loop of several cytoplasmic tRNAs (PubMed:39786990, PubMed:39786998)","subcellular_location":"Nucleus, nucleolus","url":"https://www.uniprot.org/uniprotkb/Q7Z2T5/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TRMT1L","classification":"Not Classified","n_dependent_lines":9,"n_total_lines":1208,"dependency_fraction":0.0074503311258278145},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000121486","cell_line_id":"CID001863","localizations":[{"compartment":"nucleolus_gc","grade":3},{"compartment":"nucleoplasm","grade":2}],"interactors":[{"gene":"POLR2E","stoichiometry":10.0},{"gene":"POLR2F","stoichiometry":10.0},{"gene":"POLR2H","stoichiometry":10.0},{"gene":"POLR3A","stoichiometry":10.0},{"gene":"POLR3B","stoichiometry":10.0},{"gene":"POLR3E","stoichiometry":10.0},{"gene":"POLR3F","stoichiometry":10.0},{"gene":"CRCP","stoichiometry":10.0},{"gene":"POLR3D","stoichiometry":10.0},{"gene":"POLR1C","stoichiometry":4.0}],"url":"https://opencell.sf.czbiohub.org/target/CID001863","total_profiled":1310},"omim":[{"mim_id":"611673","title":"tRNA METHYLTRANSFERASE 1-LIKE; TRMT1L","url":"https://www.omim.org/entry/611673"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Nucleoli","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/TRMT1L"},"hgnc":{"alias_symbol":[],"prev_symbol":["C1orf25"]},"alphafold":{"accession":"Q7Z2T5","domains":[{"cath_id":"-","chopping":"119-166_181-207","consensus_level":"medium","plddt":89.4065,"start":119,"end":207},{"cath_id":"3.40.50.150","chopping":"228-331_349-500_507-532","consensus_level":"medium","plddt":93.1781,"start":228,"end":532},{"cath_id":"3.30.56.70","chopping":"637-695","consensus_level":"high","plddt":93.2302,"start":637,"end":695}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q7Z2T5","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q7Z2T5-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q7Z2T5-F1-predicted_aligned_error_v6.png","plddt_mean":72.69},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TRMT1L","jax_strain_url":"https://www.jax.org/strain/search?query=TRMT1L"},"sequence":{"accession":"Q7Z2T5","fasta_url":"https://rest.uniprot.org/uniprotkb/Q7Z2T5.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q7Z2T5/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q7Z2T5"}},"corpus_meta":[{"pmid":"30149757","id":"PMC_30149757","title":"Genome-Wide Methylation Analysis Identifies NOX4 and KDM5A as Key Regulators in Inhibiting Breast Cancer Cell Proliferation by Ginsenoside Rg3.","date":"2018","source":"The American journal of Chinese medicine","url":"https://pubmed.ncbi.nlm.nih.gov/30149757","citation_count":35,"is_preprint":false},{"pmid":"17198746","id":"PMC_17198746","title":"The mouse Trm1-like gene is expressed in neural tissues and plays a role in motor coordination and exploratory behaviour.","date":"2006","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/17198746","citation_count":25,"is_preprint":false},{"pmid":"33499731","id":"PMC_33499731","title":"Subcellular relocalization and nuclear redistribution of the RNA methyltransferases TRMT1 and TRMT1L upon neuronal activation.","date":"2021","source":"RNA biology","url":"https://pubmed.ncbi.nlm.nih.gov/33499731","citation_count":15,"is_preprint":false},{"pmid":"34419719","id":"PMC_34419719","title":"A novel 13 RNA binding proteins (RBPs) signature could predict prostate cancer biochemical recurrence.","date":"2021","source":"Pathology, research and practice","url":"https://pubmed.ncbi.nlm.nih.gov/34419719","citation_count":15,"is_preprint":false},{"pmid":"39786990","id":"PMC_39786990","title":"Human TRMT1 and TRMT1L paralogs ensure the proper modification state, stability, and function of tRNAs.","date":"2025","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/39786990","citation_count":14,"is_preprint":false},{"pmid":"39786998","id":"PMC_39786998","title":"TRMT1L-catalyzed m22G27 on tyrosine tRNA is required for efficient mRNA translation and cell survival under oxidative stress.","date":"2025","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/39786998","citation_count":13,"is_preprint":false},{"pmid":"39067134","id":"PMC_39067134","title":"A susceptibility gene signature for ERBB2-driven mammary tumour development and metastasis in collaborative cross mice.","date":"2024","source":"EBioMedicine","url":"https://pubmed.ncbi.nlm.nih.gov/39067134","citation_count":8,"is_preprint":false},{"pmid":"39416027","id":"PMC_39416027","title":"TRMT1L-catalyzed m2 2G27 on tyrosine tRNA is required for efficient mRNA translation and cell survival under oxidative stress.","date":"2024","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/39416027","citation_count":1,"is_preprint":false},{"pmid":"41796331","id":"PMC_41796331","title":"Thermal stress responses and heat stress resilience genes in chickens are revealed through genomic and transcriptomic insights.","date":"2026","source":"Journal of animal science and biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/41796331","citation_count":1,"is_preprint":false},{"pmid":"41751972","id":"PMC_41751972","title":"Inflammation and Oxidative-Stress Pathways Are Associated with Idiopathic Sudden Hearing Loss: A Genome-Wide Association Study in 15,494 Japanese Individuals.","date":"2026","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/41751972","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7608,"output_tokens":1869,"usd":0.02543,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8798,"output_tokens":2516,"usd":0.053445,"stage2_stop_reason":"end_turn"},"total_usd":0.078875,"stage1_batch_id":"msgbatch_017qqVz33Ga63SCDwzb35XPb","stage2_batch_id":"msgbatch_01Scr2Ei9x4HJMiRGxwrmvLK","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2021,\n      \"finding\": \"TRMT1L is responsible for methylating a subset of cytosolic tRNAAla(AGC) isodecoders at position 26, producing the N2,N2-dimethylguanosine (m2,2G) modification; prior to this work, TRMT1L's enzymatic activity was unknown.\",\n      \"method\": \"Next-generation sequencing, LC-MS/MS, patient-derived cell lines, and knockout mouse models\",\n      \"journal\": \"RNA biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — multiple orthogonal methods (sequencing, mass spectrometry, KO models) in a single study directly demonstrating enzymatic activity\",\n      \"pmids\": [\"33499731\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Upon neuronal activation (mimicking long-term potentiation) in vitro, TRMT1L undergoes subcellular relocalization from nucleoli to small punctate compartments in the nucleus; this relocalization does not occur upon heat shock, indicating it is specific to neuronal activation rather than a general stress response.\",\n      \"method\": \"Cellular in vitro neuronal activation model, subcellular localization imaging (fluorescence microscopy), heat-shock control experiments\",\n      \"journal\": \"RNA biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — direct localization experiment with functional context, single lab, two orthogonal stimuli tested as controls\",\n      \"pmids\": [\"33499731\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TRMT1L is the enzyme catalyzing m2,2G at position 27 of tyrosine tRNAs (tRNA-Tyr), a modification distinct from TRMT1's activity at position 26; additionally, TRMT1L is required for maintaining 3-(3-amino-3-carboxypropyl)uridine (acp3U) modifications in a subset of tRNAs through a process that can be uncoupled from its methyltransferase activity.\",\n      \"method\": \"Comprehensive tRNA sequencing (tRNA-seq), LC-MS/MS, TRMT1L knockout cell lines\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — replicated independently across two labs (PMID 39786990 and 39786998) using multiple orthogonal sequencing and mass spectrometry methods\",\n      \"pmids\": [\"39786990\", \"39786998\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TRMT1L depletion impairs deposition of acp3U and dihydrouridine on tRNA-Tyr-GUA, tRNA-Cys-GCA, and tRNA-Ala-CGC, indicating TRMT1L participates in a tRNA modification circuit beyond its direct methyltransferase activity.\",\n      \"method\": \"eCLIP-seq, nanopore tRNA-seq, TRMT1L knockout/depletion cell lines\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — replicated in two independent studies using multiple orthogonal sequencing methods\",\n      \"pmids\": [\"39786990\", \"39786998\", \"39416027\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TRMT1L knockout cells exhibit decreased tRNA-Tyr-GUA levels, reduced global mRNA translation rates, and hypersensitivity to oxidative stress, establishing a functional link between TRMT1L-catalyzed m2,2G27 and translational regulation and cell survival under stress.\",\n      \"method\": \"TRMT1L knockout cell lines, global translation rate assays, oxidative stress viability assays\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean KO with defined cellular phenotypes (translation, stress survival), replicated across two independent studies\",\n      \"pmids\": [\"39786998\", \"39416027\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"TRMT1L interacts with a component of the Rix1 ribosome biogenesis complex and binds to 28S rRNA as well as a subset of tRNAs, as determined by eCLIP-seq.\",\n      \"method\": \"eCLIP-seq\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — eCLIP-seq identifies binding partners, single lab, no reciprocal validation reported in abstract\",\n      \"pmids\": [\"39786998\", \"39416027\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Tyrosine and serine tRNAs are dependent upon m2,2G modifications for their stability and function in translation; human patient cells with disease-associated TRMT1 variants exhibit reduced levels of tyrosine and serine tRNAs.\",\n      \"method\": \"tRNA-seq in TRMT1L/TRMT1 knockout and patient-derived cell lines, translation functional assays\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO and patient-derived cells with direct tRNA quantification, single study\",\n      \"pmids\": [\"39786990\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Mouse Trm1-like (ortholog of human TRMT1L/C1orf25), when disrupted by gene-trap insertion in the first intron, causes significantly altered motor coordination and aberrant exploratory behaviour in viable mice, with expression detected in neural tissues including spinal ganglia, trigeminal nerve, olfactory epithelium, and brain nuclei during embryogenesis and in adult brain.\",\n      \"method\": \"Gene-trap mouse model, behavioral testing (motor coordination and exploratory behavior), LacZ reporter for expression mapping\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — clean loss-of-function model with defined behavioral phenotype and expression mapping, single lab\",\n      \"pmids\": [\"17198746\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TRMT1L is a tRNA methyltransferase that specifically catalyzes N2,N2-dimethylguanosine (m2,2G) at position 27 of tyrosine tRNAs (and position 26 of a subset of tRNAAla isodecoders), and also facilitates deposition of acp3U and dihydrouridine modifications on select tRNAs through a process separable from its methyltransferase activity; loss of TRMT1L reduces tRNA-Tyr levels, globally impairs mRNA translation, and increases sensitivity to oxidative stress, while upon neuronal activation TRMT1L redistributes from nucleoli to nuclear puncta in a stimulus-specific manner, implicating it in neuronal plasticity.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TRMT1L is a tRNA methyltransferase that shapes the cytosolic tRNA modification landscape and, through it, global translation and stress resilience [#2, #4]. It catalyzes N2,N2-dimethylguanosine (m2,2G): at position 26 of a subset of tRNA-Ala(AGC) isodecoders [#0] and, distinct from the related TRMT1 activity, at position 27 of tyrosine tRNAs [#2]. Beyond direct methylation, TRMT1L is required for deposition of acp3U and dihyduridine on select tRNAs (tRNA-Tyr-GUA, tRNA-Cys-GCA, tRNA-Ala-CGC) through a circuit that can be uncoupled from its methyltransferase activity, placing it within a broader tRNA-modification network [#2, #3]. Loss of TRMT1L reduces tRNA-Tyr-GUA levels, lowers global mRNA translation rates, and renders cells hypersensitive to oxidative stress [#4]. Consistent with a role in ribosome and tRNA biology, TRMT1L interacts with a component of the Rix1 ribosome biogenesis complex and binds 28S rRNA and a subset of tRNAs [#5]. In neurons, TRMT1L relocalizes from nucleoli to nuclear puncta specifically upon neuronal activation but not heat shock [#1], and disruption of its mouse ortholog produces altered motor coordination and exploratory behavior with expression in neural tissues [#7], linking the enzyme to neuronal function.\",\n  \"teleology\": [\n    {\n      \"year\": 2006,\n      \"claim\": \"Before any molecular activity was known, loss-of-function in the mouse ortholog established that TRMT1L has a physiological role in the nervous system, framing it as a brain-relevant gene.\",\n      \"evidence\": \"Gene-trap mouse model with behavioral testing and LacZ expression mapping\",\n      \"pmids\": [\"17198746\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"No molecular mechanism connecting the behavioral phenotype to a biochemical activity\", \"Single lab\", \"Gene-trap may not be a complete null\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"The first enzymatic assignment showed TRMT1L is an active m2,2G methyltransferase, resolving its long-unknown biochemical function.\",\n      \"evidence\": \"NGS, LC-MS/MS, patient-derived and knockout mouse cell lines identifying m2,2G at position 26 of tRNA-Ala(AGC) isodecoders\",\n      \"pmids\": [\"33499731\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Did not yet define the full substrate repertoire (tRNA-Tyr position 27 came later)\", \"Functional consequence for translation not established in this work\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Subcellular imaging linked the enzyme to neuronal plasticity by showing stimulus-specific relocalization, distinguishing it from a generic stress response.\",\n      \"evidence\": \"In vitro neuronal activation model with fluorescence microscopy and heat-shock control\",\n      \"pmids\": [\"33499731\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Identity and function of the nuclear puncta unknown\", \"Mechanism coupling activation to relocalization not defined\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Independent studies defined tRNA-Tyr position 27 as the principal m2,2G target and revealed a methyltransferase-uncoupled role in acp3U/dihydrouridine deposition, expanding TRMT1L from a single-mark enzyme to a node in a tRNA modification circuit.\",\n      \"evidence\": \"tRNA-seq, nanopore tRNA-seq, eCLIP-seq and LC-MS/MS in knockout/depletion cell lines, replicated across labs\",\n      \"pmids\": [\"39786990\", \"39786998\", \"39416027\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Mechanism by which TRMT1L promotes acp3U/dihydrouridine independent of catalysis is unknown\", \"Enzymes it cooperates with for those marks not identified\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Phenotypic analysis tied the molecular activity to organism-level consequences: TRMT1L loss destabilizes tRNA-Tyr, depresses global translation, and sensitizes cells to oxidative stress.\",\n      \"evidence\": \"Knockout cell lines with global translation rate assays and oxidative stress viability assays\",\n      \"pmids\": [\"39786998\", \"39416027\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Causal chain from m2,2G27 loss to oxidative stress sensitivity not mechanistically dissected\", \"Codon-specific translational effects not mapped\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Binding studies positioned TRMT1L within ribosome biogenesis machinery, suggesting its tRNA role intersects with rRNA/ribosome processing.\",\n      \"evidence\": \"eCLIP-seq showing interaction with a Rix1 complex component and binding to 28S rRNA and tRNAs\",\n      \"pmids\": [\"39786998\", \"39416027\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"No reciprocal validation of the Rix1 component interaction\", \"Functional consequence of 28S rRNA binding unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How TRMT1L mechanistically promotes acp3U and dihydrouridine without catalyzing them, and how its activation-dependent nuclear relocalization connects to translational control in neurons, remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Non-catalytic mechanism for acp3U/DHU support undefined\", \"Molecular link between neuronal relocalization and tRNA modification not established\", \"No structural model of substrate recognition\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0140098\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [0, 2, 3]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"complexes\": [],\n    \"partners\": [],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}