{"gene":"MRPL39","run_date":"2026-06-10T02:59:51","timeline":{"discoveries":[{"year":2000,"finding":"MRPL39 (MRP-L5) is a 338 amino acid mitochondrial ribosomal large subunit protein. A heart-specific splice variant (MRP-L5V1, 353 aa) was identified, generated by insertion of an 89-nucleotide exon prior to the last exon, creating a premature stop codon. Sequence analysis and 3D modeling revealed similarity to threonyl-tRNA synthetases and a likely RNA binding site, with the C-terminus in proximity to the RNA binding site; the splice variant C-terminus was predicted to gain a transmembrane domain that may interfere with RNA binding.","method":"EST database screening, cDNA library screening, sequencing, 3D structural modeling","journal":"Gene","confidence":"Low","confidence_rationale":"Tier 4 / Weak — structural similarity and functional implications based on computational modeling only; no biochemical or functional validation of RNA binding or transmembrane domain reported","pmids":["11167009"],"is_preprint":false},{"year":2013,"finding":"In Saccharomyces cerevisiae, MRPL39 (the yeast ortholog) is part of the mitochondrial large ribosomal subunit (LSU). The DEAD box protein Mrh4 is required for late-stage LSU assembly; in the absence of Mrh4, a large on-pathway assembly intermediate accumulates that is missing both Mrpl16 and Mrpl39, demonstrating that Mrpl39 incorporation occurs during a late step of mitoribosome assembly promoted by Mrh4-mediated rRNA remodeling.","method":"Genetic deletion (Mrh4 knockout), sucrose gradient sedimentation, mass spectrometry identification of subunit composition of assembly intermediates","journal":"Cell Metabolism","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KO with defined biochemical phenotype and MS-based identification of assembly intermediate composition, single lab study in yeast ortholog","pmids":["24206665"],"is_preprint":false},{"year":2023,"finding":"Biallelic pathogenic variants in MRPL39 cause mitochondrial disease in humans. Quantitative proteomics of patient fibroblasts demonstrated a specific decrease in the abundance of large mitoribosomal subunit proteins but not small subunit proteins, indicating that MRPL39 variants destabilize the large mitoribosomal subunit (LSU). This LSU instability leads to reduced synthesis of the 13 mtDNA-encoded OXPHOS subunits, causing multisystem disease ranging from lethal infantile Leigh syndrome to milder adult-onset phenotypes.","method":"Multi-omics: quantitative proteomics (Relative Complex Abundance analysis), exome/genome sequencing, transcriptomics, targeted functional studies in patient fibroblasts","journal":"Human Molecular Genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (proteomics, genomics, transcriptomics) in patient-derived cells, replicated across three unrelated individuals","pmids":["37133451"],"is_preprint":false},{"year":2024,"finding":"MRPL39 was validated as a novel mitochondrial disease gene through targeted functional studies in critically ill infants undergoing ultrarapid genomic sequencing, confirming its pathogenicity in OXPHOS-related disease.","method":"Ultrarapid genomic sequencing, targeted functional studies (details not specified in abstract)","journal":"Genetics in Medicine","confidence":"Low","confidence_rationale":"Tier 3 / Weak — functional validation mentioned but methods not detailed in abstract; single case report context","pmids":["39417332"],"is_preprint":false}],"current_model":"MRPL39 encodes a protein component of the large subunit of the mitochondrial ribosome (mitoribosome); its incorporation into the LSU occurs at a late stage of mitoribosome assembly (dependent on the RNA helicase Mrh4 in yeast), and loss-of-function variants in humans cause specific instability of the large mitoribosomal subunit—but not the small subunit—resulting in impaired synthesis of mtDNA-encoded OXPHOS subunits and multisystem mitochondrial disease."},"narrative":{"mechanistic_narrative":"MRPL39 encodes a protein component of the large subunit (LSU) of the mitochondrial ribosome [PMID:24206665, PMID:37133451]. Studies of the yeast ortholog place its incorporation at a late step of mitoribosome assembly: in the absence of the DEAD-box RNA helicase Mrh4, an on-pathway assembly intermediate accumulates that lacks both Mrpl16 and Mrpl39, indicating that Mrh4-mediated rRNA remodeling licenses Mrpl39 addition during LSU maturation [PMID:24206665]. In humans, biallelic pathogenic variants in MRPL39 cause multisystem mitochondrial disease; quantitative proteomics of patient fibroblasts shows a selective decrease in LSU proteins but not small-subunit proteins, demonstrating that loss of MRPL39 specifically destabilizes the large mitoribosomal subunit and thereby impairs synthesis of the 13 mtDNA-encoded OXPHOS subunits, with phenotypes ranging from lethal infantile Leigh syndrome to milder adult-onset disease [PMID:37133451]. Early sequence and structural modeling noted similarity to threonyl-tRNA synthetases and a candidate RNA-binding site, and identified a heart-specific splice variant predicted to alter RNA binding [PMID:11167009], but these features remain computational and uncharacterized biochemically in the available corpus.","teleology":[{"year":2000,"claim":"Established MRPL39 as a mitochondrial large-subunit ribosomal protein and raised the first structural hypotheses about its function, framing it as a potential RNA-binding component with tissue-specific isoform regulation.","evidence":"EST/cDNA library screening, sequencing, and 3D structural modeling identifying a 338-aa protein and a heart-specific 353-aa splice variant","pmids":["11167009"],"confidence":"Low","gaps":["RNA binding and the predicted threonyl-tRNA-synthetase-like fold were inferred from modeling only, not biochemically validated","Functional consequence of the heart-specific splice variant was not tested","No direct demonstration of incorporation into the mitoribosome"]},{"year":2013,"claim":"Defined when MRPL39 joins the mitoribosome by showing its incorporation is a late, helicase-dependent step of LSU assembly, distinguishing it from early-assembling components.","evidence":"Mrh4 genetic deletion in S. cerevisiae with sucrose-gradient sedimentation and mass spectrometry of accumulated assembly intermediates","pmids":["24206665"],"confidence":"Medium","gaps":["Demonstrated in the yeast ortholog; late-assembly timing not directly confirmed in human cells","Does not define the specific molecular contacts MRPL39 makes within the mature LSU","Mechanism of rRNA remodeling that permits MRPL39 addition not resolved at structural level"]},{"year":2023,"claim":"Connected MRPL39 loss-of-function to human disease and established its mechanism: specific LSU destabilization that selectively impairs mtDNA-encoded OXPHOS subunit synthesis.","evidence":"Quantitative proteomics (Relative Complex Abundance), exome/genome sequencing, and transcriptomics in patient fibroblasts across three unrelated individuals","pmids":["37133451"],"confidence":"High","gaps":["Does not establish whether destabilization reflects failed assembly versus accelerated turnover of the LSU","Genotype-phenotype basis for the broad severity spectrum not mechanistically explained","No structural model of how patient variants disrupt LSU integration"]},{"year":2024,"claim":"Reinforced MRPL39 as a bona fide OXPHOS disease gene in an independent clinical-genomic setting.","evidence":"Ultrarapid genomic sequencing with targeted functional studies in critically ill infants","pmids":["39417332"],"confidence":"Low","gaps":["Functional validation methods not detailed in the source","Single clinical context; adds confirmation rather than new mechanism","No new biochemical insight into MRPL39 function"]},{"year":null,"claim":"How MRPL39 is structurally positioned within the human LSU and the precise molecular basis by which pathogenic variants prevent its incorporation or destabilize the subunit remain unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No experimentally validated RNA-binding or catalytic activity for the human protein","No structural mapping of variant effects on LSU assembly","Functional relevance of the heart-specific splice isoform untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[1,2]}],"localization":[{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[0,1,2]}],"pathway":[{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[2]}],"complexes":["mitochondrial large ribosomal subunit (mitoribosome LSU)"],"partners":[],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9NYK5","full_name":"Large ribosomal subunit protein mL39","aliases":["39S ribosomal protein L39, mitochondrial","L39mt","MRP-L39","39S ribosomal protein L5, mitochondrial","L5mt","MRP-L5"],"length_aa":338,"mass_kda":38.7,"function":"","subcellular_location":"Mitochondrion","url":"https://www.uniprot.org/uniprotkb/Q9NYK5/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/MRPL39","classification":"Common Essential","n_dependent_lines":815,"n_total_lines":1208,"dependency_fraction":0.6746688741721855},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"EWSR1","stoichiometry":0.2},{"gene":"NPM1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/MRPL39","total_profiled":1310},"omim":[{"mim_id":"620646","title":"COMBINED OXIDATIVE PHOSPHORYLATION DEFICIENCY 59; COXPD59","url":"https://www.omim.org/entry/620646"},{"mim_id":"611845","title":"MITOCHONDRIAL RIBOSOMAL PROTEIN L39; MRPL39","url":"https://www.omim.org/entry/611845"},{"mim_id":"609060","title":"COMBINED OXIDATIVE PHOSPHORYLATION DEFICIENCY 1; COXPD1","url":"https://www.omim.org/entry/609060"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Mitochondria","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/MRPL39"},"hgnc":{"alias_symbol":["RPML5","MRP-L5","MGC104174","PRED66","PRED22","C21orf92","L39mt","MSTP003","MGC3400","FLJ20451","mL39"],"prev_symbol":[]},"alphafold":{"accession":"Q9NYK5","domains":[{"cath_id":"3.10.20.30","chopping":"65-129","consensus_level":"high","plddt":93.1455,"start":65,"end":129},{"cath_id":"3.30.980.10","chopping":"136-321","consensus_level":"high","plddt":92.2764,"start":136,"end":321}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NYK5","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NYK5-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NYK5-F1-predicted_aligned_error_v6.png","plddt_mean":84.12},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MRPL39","jax_strain_url":"https://www.jax.org/strain/search?query=MRPL39"},"sequence":{"accession":"Q9NYK5","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9NYK5.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9NYK5/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NYK5"}},"corpus_meta":[{"pmid":"17284669","id":"PMC_17284669","title":"Identification of reference genes for quantitative real-time PCR in the bovine mammary gland during the lactation cycle.","date":"2007","source":"Physiological genomics","url":"https://pubmed.ncbi.nlm.nih.gov/17284669","citation_count":250,"is_preprint":false},{"pmid":"23552195","id":"PMC_23552195","title":"Selection of reference genes for quantitative real-time PCR normalisation in adipose tissue, muscle, liver and mammary gland from ruminants.","date":"2013","source":"Animal : an international journal of animal bioscience","url":"https://pubmed.ncbi.nlm.nih.gov/23552195","citation_count":85,"is_preprint":false},{"pmid":"19389958","id":"PMC_19389958","title":"Identification of internal control genes for quantitative polymerase chain reaction in mammary tissue of lactating cows receiving lipid supplements.","date":"2009","source":"Journal of dairy science","url":"https://pubmed.ncbi.nlm.nih.gov/19389958","citation_count":74,"is_preprint":false},{"pmid":"24206665","id":"PMC_24206665","title":"The DEAD box protein Mrh4 functions in the assembly of the mitochondrial large ribosomal subunit.","date":"2013","source":"Cell metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/24206665","citation_count":44,"is_preprint":false},{"pmid":"18650282","id":"PMC_18650282","title":"Internal controls for quantitative polymerase chain reaction of swine mammary glands during pregnancy and lactation.","date":"2008","source":"Journal of dairy science","url":"https://pubmed.ncbi.nlm.nih.gov/18650282","citation_count":37,"is_preprint":false},{"pmid":"37133451","id":"PMC_37133451","title":"Multi-omics identifies large mitoribosomal subunit instability caused by pathogenic MRPL39 variants as a cause of pediatric onset mitochondrial disease.","date":"2023","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/37133451","citation_count":23,"is_preprint":false},{"pmid":"26808329","id":"PMC_26808329","title":"Evaluation of Suitable Internal Control Genes for RT-qPCR in Yak Mammary Tissue during the Lactation Cycle.","date":"2016","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/26808329","citation_count":18,"is_preprint":false},{"pmid":"11167009","id":"PMC_11167009","title":"Heart-specific splice-variant of a human mitochondrial ribosomal protein (mRNA processing; tissue specific splicing).","date":"2000","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/11167009","citation_count":17,"is_preprint":false},{"pmid":"30452299","id":"PMC_30452299","title":"Long Noncoding RNA MRPL39 Inhibits Gastric Cancer Proliferation and Progression by Directly Targeting miR-130.","date":"2018","source":"Genetic testing and molecular biomarkers","url":"https://pubmed.ncbi.nlm.nih.gov/30452299","citation_count":11,"is_preprint":false},{"pmid":"37215987","id":"PMC_37215987","title":"Upregulated Long Non-coding RNA Lnc-MRPL39-2:1 Induces the Growth and Invasion of Nasopharyngeal Carcinoma by Binding to HuR and Stabilizing β-Catenin mRNA.","date":"2023","source":"International journal of biological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37215987","citation_count":11,"is_preprint":false},{"pmid":"24893875","id":"PMC_24893875","title":"Identification of reference genes for RT-qPCR in ovine mammary tissue during late pregnancy and lactation and in response to maternal nutritional programming.","date":"2014","source":"Physiological genomics","url":"https://pubmed.ncbi.nlm.nih.gov/24893875","citation_count":9,"is_preprint":false},{"pmid":"19328224","id":"PMC_19328224","title":"Upregulation of beta-catenin expression in down syndrome model Ts65Dn mouse brain.","date":"2009","source":"Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/19328224","citation_count":6,"is_preprint":false},{"pmid":"36465357","id":"PMC_36465357","title":"Establishment of a risk model correlated with metabolism based on RNA-binding proteins associated with cell pyroptosis in acute myeloid leukemia.","date":"2022","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/36465357","citation_count":5,"is_preprint":false},{"pmid":"21943746","id":"PMC_21943746","title":"A simple analytical and experimental procedure for selection of reference genes for reverse-transcription quantitative PCR normalization data.","date":"2011","source":"Journal of dairy science","url":"https://pubmed.ncbi.nlm.nih.gov/21943746","citation_count":3,"is_preprint":false},{"pmid":"39417332","id":"PMC_39417332","title":"Critically unwell infants and children with mitochondrial disorders diagnosed by ultrarapid genomic sequencing.","date":"2024","source":"Genetics in medicine : official journal of the American College of Medical Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/39417332","citation_count":3,"is_preprint":false},{"pmid":"36899781","id":"PMC_36899781","title":"Transcriptome-Based Evaluation of Optimal Reference Genes for Quantitative Real-Time PCR in Yak Stomach throughout the Growth Cycle.","date":"2023","source":"Animals : an open access journal from MDPI","url":"https://pubmed.ncbi.nlm.nih.gov/36899781","citation_count":2,"is_preprint":false},{"pmid":"34130620","id":"PMC_34130620","title":"Comparisons among rainbow trout, Oncorhynchus mykiss, populations of maternal transcript profile associated with egg viability.","date":"2021","source":"BMC genomics","url":"https://pubmed.ncbi.nlm.nih.gov/34130620","citation_count":2,"is_preprint":false},{"pmid":"38577417","id":"PMC_38577417","title":"LncRNA MRPL39 inhibits cell proliferation and migration by regulating miR-130/TSC1 axis in non-small cell lung cancer.","date":"2024","source":"3 Biotech","url":"https://pubmed.ncbi.nlm.nih.gov/38577417","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":12040,"output_tokens":1147,"usd":0.026662,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":7809,"output_tokens":1983,"usd":0.04431,"stage2_stop_reason":"end_turn"},"total_usd":0.070972,"stage1_batch_id":"msgbatch_01BbTCMyrRPyhtEq6b1MdwCN","stage2_batch_id":"msgbatch_011dEed5bbxYvTAaQWKJevxu","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2000,\n      \"finding\": \"MRPL39 (MRP-L5) is a 338 amino acid mitochondrial ribosomal large subunit protein. A heart-specific splice variant (MRP-L5V1, 353 aa) was identified, generated by insertion of an 89-nucleotide exon prior to the last exon, creating a premature stop codon. Sequence analysis and 3D modeling revealed similarity to threonyl-tRNA synthetases and a likely RNA binding site, with the C-terminus in proximity to the RNA binding site; the splice variant C-terminus was predicted to gain a transmembrane domain that may interfere with RNA binding.\",\n      \"method\": \"EST database screening, cDNA library screening, sequencing, 3D structural modeling\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — structural similarity and functional implications based on computational modeling only; no biochemical or functional validation of RNA binding or transmembrane domain reported\",\n      \"pmids\": [\"11167009\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"In Saccharomyces cerevisiae, MRPL39 (the yeast ortholog) is part of the mitochondrial large ribosomal subunit (LSU). The DEAD box protein Mrh4 is required for late-stage LSU assembly; in the absence of Mrh4, a large on-pathway assembly intermediate accumulates that is missing both Mrpl16 and Mrpl39, demonstrating that Mrpl39 incorporation occurs during a late step of mitoribosome assembly promoted by Mrh4-mediated rRNA remodeling.\",\n      \"method\": \"Genetic deletion (Mrh4 knockout), sucrose gradient sedimentation, mass spectrometry identification of subunit composition of assembly intermediates\",\n      \"journal\": \"Cell Metabolism\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined biochemical phenotype and MS-based identification of assembly intermediate composition, single lab study in yeast ortholog\",\n      \"pmids\": [\"24206665\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Biallelic pathogenic variants in MRPL39 cause mitochondrial disease in humans. Quantitative proteomics of patient fibroblasts demonstrated a specific decrease in the abundance of large mitoribosomal subunit proteins but not small subunit proteins, indicating that MRPL39 variants destabilize the large mitoribosomal subunit (LSU). This LSU instability leads to reduced synthesis of the 13 mtDNA-encoded OXPHOS subunits, causing multisystem disease ranging from lethal infantile Leigh syndrome to milder adult-onset phenotypes.\",\n      \"method\": \"Multi-omics: quantitative proteomics (Relative Complex Abundance analysis), exome/genome sequencing, transcriptomics, targeted functional studies in patient fibroblasts\",\n      \"journal\": \"Human Molecular Genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (proteomics, genomics, transcriptomics) in patient-derived cells, replicated across three unrelated individuals\",\n      \"pmids\": [\"37133451\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"MRPL39 was validated as a novel mitochondrial disease gene through targeted functional studies in critically ill infants undergoing ultrarapid genomic sequencing, confirming its pathogenicity in OXPHOS-related disease.\",\n      \"method\": \"Ultrarapid genomic sequencing, targeted functional studies (details not specified in abstract)\",\n      \"journal\": \"Genetics in Medicine\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — functional validation mentioned but methods not detailed in abstract; single case report context\",\n      \"pmids\": [\"39417332\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MRPL39 encodes a protein component of the large subunit of the mitochondrial ribosome (mitoribosome); its incorporation into the LSU occurs at a late stage of mitoribosome assembly (dependent on the RNA helicase Mrh4 in yeast), and loss-of-function variants in humans cause specific instability of the large mitoribosomal subunit—but not the small subunit—resulting in impaired synthesis of mtDNA-encoded OXPHOS subunits and multisystem mitochondrial disease.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"MRPL39 encodes a protein component of the large subunit (LSU) of the mitochondrial ribosome [#1, #2]. Studies of the yeast ortholog place its incorporation at a late step of mitoribosome assembly: in the absence of the DEAD-box RNA helicase Mrh4, an on-pathway assembly intermediate accumulates that lacks both Mrpl16 and Mrpl39, indicating that Mrh4-mediated rRNA remodeling licenses Mrpl39 addition during LSU maturation [#1]. In humans, biallelic pathogenic variants in MRPL39 cause multisystem mitochondrial disease; quantitative proteomics of patient fibroblasts shows a selective decrease in LSU proteins but not small-subunit proteins, demonstrating that loss of MRPL39 specifically destabilizes the large mitoribosomal subunit and thereby impairs synthesis of the 13 mtDNA-encoded OXPHOS subunits, with phenotypes ranging from lethal infantile Leigh syndrome to milder adult-onset disease [#2]. Early sequence and structural modeling noted similarity to threonyl-tRNA synthetases and a candidate RNA-binding site, and identified a heart-specific splice variant predicted to alter RNA binding [#0], but these features remain computational and uncharacterized biochemically in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Established MRPL39 as a mitochondrial large-subunit ribosomal protein and raised the first structural hypotheses about its function, framing it as a potential RNA-binding component with tissue-specific isoform regulation.\",\n      \"evidence\": \"EST/cDNA library screening, sequencing, and 3D structural modeling identifying a 338-aa protein and a heart-specific 353-aa splice variant\",\n      \"pmids\": [\"11167009\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"RNA binding and the predicted threonyl-tRNA-synthetase-like fold were inferred from modeling only, not biochemically validated\",\n        \"Functional consequence of the heart-specific splice variant was not tested\",\n        \"No direct demonstration of incorporation into the mitoribosome\"\n      ]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Defined when MRPL39 joins the mitoribosome by showing its incorporation is a late, helicase-dependent step of LSU assembly, distinguishing it from early-assembling components.\",\n      \"evidence\": \"Mrh4 genetic deletion in S. cerevisiae with sucrose-gradient sedimentation and mass spectrometry of accumulated assembly intermediates\",\n      \"pmids\": [\"24206665\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Demonstrated in the yeast ortholog; late-assembly timing not directly confirmed in human cells\",\n        \"Does not define the specific molecular contacts MRPL39 makes within the mature LSU\",\n        \"Mechanism of rRNA remodeling that permits MRPL39 addition not resolved at structural level\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Connected MRPL39 loss-of-function to human disease and established its mechanism: specific LSU destabilization that selectively impairs mtDNA-encoded OXPHOS subunit synthesis.\",\n      \"evidence\": \"Quantitative proteomics (Relative Complex Abundance), exome/genome sequencing, and transcriptomics in patient fibroblasts across three unrelated individuals\",\n      \"pmids\": [\"37133451\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Does not establish whether destabilization reflects failed assembly versus accelerated turnover of the LSU\",\n        \"Genotype-phenotype basis for the broad severity spectrum not mechanistically explained\",\n        \"No structural model of how patient variants disrupt LSU integration\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Reinforced MRPL39 as a bona fide OXPHOS disease gene in an independent clinical-genomic setting.\",\n      \"evidence\": \"Ultrarapid genomic sequencing with targeted functional studies in critically ill infants\",\n      \"pmids\": [\"39417332\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Functional validation methods not detailed in the source\",\n        \"Single clinical context; adds confirmation rather than new mechanism\",\n        \"No new biochemical insight into MRPL39 function\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How MRPL39 is structurally positioned within the human LSU and the precise molecular basis by which pathogenic variants prevent its incorporation or destabilize the subunit remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No experimentally validated RNA-binding or catalytic activity for the human protein\",\n        \"No structural mapping of variant effects on LSU assembly\",\n        \"Functional relevance of the heart-specific splice isoform untested\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [1, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [0, 1, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"complexes\": [\"mitochondrial large ribosomal subunit (mitoribosome LSU)\"],\n    \"partners\": [],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"faith_supported":4,"faith_total":4,"faith_pct":100.0}}