{"gene":"ERI1","run_date":"2026-04-28T17:46:03","timeline":{"discoveries":[{"year":2013,"finding":"Crystal structure of the ternary complex of human SLBP RNA binding domain, human 3'hExo (ERI1), and a 26-nucleotide stem-loop RNA revealed that only one base of the stem-loop is recognized specifically by SLBP, both proteins primarily recognize RNA shape, SLBP and 3'hExo have no direct protein-protein contact, and induced structural changes in the loop mediate cooperative binding; the 3' flanking sequence is positioned in the 3'hExo active site but the ternary complex limits the extent of trimming.","method":"X-ray crystallography of ternary complex","journal":"Science","confidence":"High","confidence_rationale":"Tier 1 — crystal structure at atomic resolution with functional validation of cooperative binding mechanism","pmids":["23329046"],"is_preprint":false},{"year":2004,"finding":"Crystal structure of the nuclease domain of 3'hExo (ERI1) bound to rAMP with Mg2+ showed it adopts a DEDDh family alpha/beta fold with a binuclear metal cluster coordinated by D134, E136, D234, D298, and H293 acting as general base for hydrolytic RNA cleavage in the 3'→5' direction; the 2'-OH and 3'-OH groups of the substrate are required for efficient degradation.","method":"X-ray crystallography at 1.6 Å resolution; mutagenesis and in vitro exonuclease assays","journal":"Journal of Molecular Biology","confidence":"High","confidence_rationale":"Tier 1 — atomic resolution structure with active site characterization and biochemical validation","pmids":["15451662"],"is_preprint":false},{"year":2006,"finding":"3'hExo (ERI1) specifically binds the 3' stem-loop of histone mRNA via its SAP domain and two lysines C-terminal to it; catalytic activity requires the DEDDh active site residues; 3'hExo trims 3' overhangs of siRNAs but cannot degrade double-stranded regions; it localizes predominantly to the cytoplasm and has only residual activity on DNA substrates.","method":"Site-directed mutagenesis, in vitro RNA binding and exonuclease assays, subcellular fractionation/localization","journal":"Journal of Biological Chemistry","confidence":"High","confidence_rationale":"Tier 1 — mutagenesis dissecting RNA binding vs. catalytic residues with orthogonal biochemical assays","pmids":["16912046"],"is_preprint":false},{"year":2008,"finding":"Mouse Eri1 associates with ribosomes and ribosomal RNA, and catalyzes the final 3' end trimming step of 5.8S rRNA; catalytically inactive Eri1 mutant fails to rescue aberrant 5.8S rRNA extension in Eri1-deficient cells; RNA binding via the SAP and linker domains promotes stable rRNA association and facilitates processing; Eri1 localizes to cytoplasm and nucleolus.","method":"Ribosome co-sedimentation, in vitro rRNA processing assay with wild-type vs. catalytic mutant, subcellular localization (immunofluorescence), rescue experiments in Eri1-deficient cells","journal":"Nature Structural & Molecular Biology","confidence":"High","confidence_rationale":"Tier 1-2 — multiple orthogonal methods including in vitro reconstitution, catalytic mutant, and cellular rescue","pmids":["18438418"],"is_preprint":false},{"year":2008,"finding":"ERI-1 performs 3' end processing of 5.8S rRNA in both C. elegans and S. pombe, and two protein isoforms of C. elegans ERI-1 localize to the cytoplasm with distinct functions in rRNA processing and negative regulation of RNA interference.","method":"Genetic analysis in C. elegans and S. pombe, isoform characterization, subcellular localization","journal":"Nature Structural & Molecular Biology","confidence":"High","confidence_rationale":"Tier 2 — genetic and biochemical evidence replicated across two organisms","pmids":["18438419"],"is_preprint":false},{"year":2012,"finding":"Eri1 degrades the stem-loop of oligouridylated histone mRNAs to initiate replication-dependent decay: Eri1 trims mature histone mRNAs by two unpaired nucleotides at the 3' end but stalls at the double-stranded stem; upon oligouridylation, the Lsm1-7 heteroheptamer recognizes the oligo(U) tail and interacts with Eri1, enabling Eri1's catalytic activity to degrade the stem-loop in a stepwise manner. Eri1-deficient mouse cells accumulate oligouridylated histone mRNAs with impaired degradation.","method":"Eri1-deficient mouse cell analysis, RNA sequencing, Co-IP of Lsm1-7 with Eri1, in vitro RNA degradation assays, mutagenesis","journal":"Nature Structural & Molecular Biology","confidence":"High","confidence_rationale":"Tier 1-2 — multiple orthogonal methods, KO cells with specific molecular phenotype plus biochemical reconstitution of stepwise degradation","pmids":["23202588"],"is_preprint":false},{"year":2012,"finding":"Eri1 regulates miRNA homeostasis in mouse lymphocytes; Eri1-deficient NK and T cells display a global, sequence-independent increase in miRNA abundance; ectopic Eri1 expression rescues defective miRNA expression in mature Eri1-deficient T cells. Eri1 deficiency causes cell-intrinsic defects in NK-cell development and Ly49 receptor acquisition.","method":"Eri1 knockout mouse, small RNA profiling, reconstitution by ectopic expression, flow cytometry for NK cell phenotype","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 — KO mouse with defined molecular phenotype, rescue experiment, multiple cell types","pmids":["22613798"],"is_preprint":false},{"year":2006,"finding":"Fission yeast Eri1 specifically degrades double-stranded siRNAs through two functional domains, represses accumulation of cellular siRNAs in vivo, and deletion of eri1+ increases siRNAs associated with the RITS complex, enhancing heterochromatic silencing with increased H3-K9 methylation and Swi6 protein levels.","method":"Eri1 deletion in S. pombe, siRNA quantification, ChIP for H3-K9 methylation and Swi6, in vitro dsRNA degradation assays","journal":"Current Biology","confidence":"High","confidence_rationale":"Tier 1-2 — genetic deletion with defined chromatin phenotype plus biochemical activity assay","pmids":["16797182"],"is_preprint":false},{"year":2022,"finding":"3'hExo (ERI1) is essential for initiating histone mRNA degradation on polyribosomes at the 3' side of the stem-loop; 3'hExo cooperates with TUT7 (TENT3B/ZCCHC6) to both maintain histone mRNA length during S-phase and degrade it at S-phase end; knockout of 3'hExo prevents initiation of 3'→5' degradation and stabilizes histone mRNA, while TUT7 knockout prevents uridylation of degradation intermediates slowing degradation.","method":"CRISPR knockout of TUT7 and 3'hExo in human cells, synchronized cell analysis, RNA sequencing of degradation intermediates","journal":"RNA","confidence":"High","confidence_rationale":"Tier 2 — clean KO of two factors with defined molecular phenotypes and epistatic relationship established","pmids":["36041871"],"is_preprint":false},{"year":2020,"finding":"ERI1 interacts with the PB2, PB1, and NP components of influenza A viral ribonucleoproteins in an RNA-dependent manner, and both the RNA binding and exonuclease activities of ERI1 are required to promote influenza A virus mRNA transcription; during infection, SLBP and histone mRNAs co-purify with vRNPs alongside ERI1, suggesting ERI1 is recruited as part of the histone pre-mRNA processing complex in the nucleus.","method":"Interactomics/Co-IP, siRNA silencing, viral transcription assay, ERI1 activity mutants","journal":"Nucleic Acids Research","confidence":"Medium","confidence_rationale":"Tier 2-3 — Co-IP plus functional mutagenesis showing both activities required, but single lab","pmids":["32960265"],"is_preprint":false},{"year":2023,"finding":"ERI1 missense variants identified in patients with spondyloepimetaphyseal dysplasia cause loss of exoribonuclease activity, leading to defective trimming of the 5.8S rRNA 3' end and decreased degradation of replication-dependent histone mRNAs; patient-derived iPSCs showed impaired in vitro chondrogenesis with downregulation of skeletal patterning genes.","method":"Patient-derived cells, in vitro 5.8S rRNA processing assay, histone mRNA degradation assay, iPSC chondrogenesis differentiation","journal":"American Journal of Human Genetics","confidence":"High","confidence_rationale":"Tier 1-2 — biochemical activity assays on patient variants plus iPSC differentiation model with defined molecular phenotypes","pmids":["37352860"],"is_preprint":false},{"year":2023,"finding":"Uridylation of the histone mRNA stem-loop weakens binding interactions with SLBP while maintaining interactions with 3'hExo (ERI1); uridylation allows 3'hExo to maintain contact with the stem-loop after partial degradation and disrupts key base pairs in partially degraded histone mRNA intermediates.","method":"Fluorescence polarization, EMSA, 1-µs molecular dynamics simulations","journal":"RNA Biology","confidence":"Medium","confidence_rationale":"Tier 2-3 — biophysical binding assays with computational support, single lab","pmids":["37516934"],"is_preprint":false},{"year":2017,"finding":"Drosophila Snipper (ERI1 homolog) directly interacts with histone mRNA; its depletion causes drastic reduction in histone transcript levels, suggesting Snp protects histone mRNA 3'-ends from degradation; Snp perturbation leads to larval arrest and tissue-specific developmental abnormalities.","method":"RNA immunoprecipitation, RNAi knockdown, developmental phenotype analysis in Drosophila","journal":"FEBS Letters","confidence":"Medium","confidence_rationale":"Tier 3 — direct binding shown by RIP with KD phenotype, but ortholog with distinct behavior from 3'hExo","pmids":["28626879"],"is_preprint":false}],"current_model":"ERI1 (3'hExo) is a conserved 3'-to-5' DEDDh-family exoribonuclease that: (1) catalyzes the final trimming step of 5.8S rRNA 3' ends by associating with ribosomes via its SAP and linker domains; (2) binds the conserved stem-loop of histone mRNAs through its SAP domain and cooperates with SLBP in a ternary complex to trim histone mRNA 3' ends by two nucleotides; (3) upon oligouridylation of histone mRNA by TUT7, is recruited via Lsm1-7 interaction to degrade the stem-loop in a stepwise manner, initiating replication-dependent histone mRNA decay; and (4) degrades siRNAs to negatively regulate RNAi and miRNA abundance in lymphocytes, linking it to immune cell development and antiviral function."},"narrative":{"teleology":[{"year":2004,"claim":"Determination of the catalytic mechanism: the crystal structure of the ERI1 nuclease domain revealed a DEDDh-family exoribonuclease fold with a binuclear metal active site, establishing the chemical basis for 3'-to-5' hydrolytic RNA cleavage and the requirement for 2'-OH and 3'-OH groups.","evidence":"1.6 Å X-ray crystal structure with bound rAMP and Mg²⁺, validated by mutagenesis and in vitro exonuclease assays","pmids":["15451662"],"confidence":"High","gaps":["No structural information yet on the SAP domain or full-length protein","Physiological RNA substrates not yet identified"]},{"year":2006,"claim":"Identification of substrate specificity and RNA-binding determinants: ERI1's SAP domain and C-terminal lysines mediate specific binding to the histone mRNA stem-loop, while the enzyme trims siRNA 3' overhangs but cannot degrade double-stranded RNA, defining its substrate scope.","evidence":"Site-directed mutagenesis separating RNA-binding from catalytic residues, in vitro binding and nuclease assays, subcellular fractionation","pmids":["16912046"],"confidence":"High","gaps":["How ERI1 is recruited to substrates in vivo remained unknown","No in vivo demonstration of siRNA degradation in mammalian cells"]},{"year":2006,"claim":"Discovery of ERI1 as a negative regulator of RNAi and heterochromatic silencing: fission yeast Eri1 degrades double-stranded siRNAs, and its deletion enhances siRNA accumulation, RITS complex loading, H3-K9 methylation, and heterochromatic gene silencing.","evidence":"S. pombe eri1Δ, siRNA quantification, ChIP for H3-K9me and Swi6, in vitro dsRNA degradation","pmids":["16797182"],"confidence":"High","gaps":["Whether mammalian ERI1 similarly regulates heterochromatic siRNA pathways was untested","Mechanism of dsRNA access by ERI1 in vivo unclear"]},{"year":2008,"claim":"Establishing ERI1 as the terminal 5.8S rRNA processing enzyme: mouse and C. elegans/S. pombe studies converged to show ERI1 catalyzes the final 3' trimming of 5.8S rRNA on ribosomes, with the SAP/linker domains mediating ribosome association, revealing a conserved housekeeping function.","evidence":"Ribosome co-sedimentation, in vitro rRNA processing with catalytic mutants, rescue in Eri1-deficient cells, cross-species genetics","pmids":["18438418","18438419"],"confidence":"High","gaps":["Structural basis of ERI1–ribosome interaction not resolved","Whether 5.8S rRNA processing defects have physiological consequences in mammals was unclear"]},{"year":2012,"claim":"Mechanistic dissection of histone mRNA decay initiation: ERI1 trims two nucleotides from mature histone mRNA but stalls at the stem; upon oligouridylation, Lsm1-7 recognizes the oligo(U) tail and facilitates ERI1's stepwise degradation of the stem-loop, establishing ERI1 as the enzyme that initiates 3'-to-5' histone mRNA degradation.","evidence":"Eri1-deficient mouse cells accumulating oligouridylated histone mRNAs, Co-IP of Lsm1-7 with Eri1, in vitro reconstitution of stepwise degradation","pmids":["23202588"],"confidence":"High","gaps":["How Lsm1-7 activates ERI1 catalytically on the stem-loop was structurally unresolved","Downstream 3'-to-5' degradation machinery after stem-loop removal not identified"]},{"year":2012,"claim":"Demonstrating ERI1's role in miRNA homeostasis and immune cell development: Eri1-deficient mouse NK and T cells show global miRNA upregulation, and Eri1 deficiency causes cell-intrinsic NK cell developmental defects, linking ERI1's exonuclease activity to immune regulation.","evidence":"Eri1 knockout mouse, small RNA profiling, ectopic expression rescue, flow cytometry for NK cell phenotyping","pmids":["22613798"],"confidence":"High","gaps":["Whether ERI1 directly degrades mature miRNAs or acts on precursors was not resolved","Mechanism of sequence-independent miRNA regulation unclear"]},{"year":2013,"claim":"Structural basis of cooperative ternary complex formation: the crystal structure of SLBP–ERI1–stem-loop RNA showed that SLBP and ERI1 lack direct protein-protein contact and instead cooperate through induced RNA conformational changes, explaining how the complex limits trimming to two nucleotides.","evidence":"X-ray crystallography of the ternary complex with functional validation","pmids":["23329046"],"confidence":"High","gaps":["How uridylation disrupts this cooperative complex to permit further degradation was not structurally captured","No dynamic or kinetic data on complex assembly/disassembly"]},{"year":2022,"claim":"Epistatic relationship between ERI1 and TUT7 in histone mRNA turnover: CRISPR knockouts showed ERI1 is essential for initiating 3'-side degradation on polyribosomes, while TUT7 uridylates intermediates to sustain degradation, establishing the ordered enzymatic logic of histone mRNA decay.","evidence":"CRISPR KO of ERI1 and TUT7 in human cells, synchronized cell cycle analysis, sequencing of degradation intermediates","pmids":["36041871"],"confidence":"High","gaps":["Whether additional nucleases act redundantly with ERI1 in histone mRNA decay was not fully excluded","Polyribosome context of decay not structurally resolved"]},{"year":2023,"claim":"Uridylation differentially modulates SLBP and ERI1 binding: uridylation of histone mRNA weakens SLBP binding while maintaining ERI1 contact, providing a biophysical mechanism for the switch from steady-state trimming to processive degradation.","evidence":"Fluorescence polarization, EMSA, and molecular dynamics simulations","pmids":["37516934"],"confidence":"Medium","gaps":["Computational predictions not yet validated by structural experiments","Single-lab study without independent replication"]},{"year":2023,"claim":"Human disease causation established: loss-of-function ERI1 missense variants cause spondyloepimetaphyseal dysplasia through impaired 5.8S rRNA trimming and histone mRNA degradation, with defective chondrogenesis in patient-derived iPSCs.","evidence":"Patient-derived cells, in vitro 5.8S rRNA and histone mRNA processing assays, iPSC chondrogenesis differentiation","pmids":["37352860"],"confidence":"High","gaps":["Whether the skeletal phenotype is driven primarily by rRNA or histone mRNA defects is unresolved","No animal model recapitulating the human skeletal phenotype reported"]},{"year":null,"claim":"Key unresolved questions include: the structural basis of ERI1's interaction with ribosomes during 5.8S rRNA processing, the mechanism by which Lsm1-7 activates ERI1 to degrade the stem-loop, whether ERI1 directly degrades mature miRNAs or acts on precursor forms, and the relative contributions of impaired rRNA versus histone mRNA processing to the skeletal dysplasia phenotype.","evidence":"","pmids":[],"confidence":"Low","gaps":["No full-length ERI1 structure on the ribosome","Lsm1-7 activation mechanism structurally unresolved","Direct vs. indirect miRNA regulation not distinguished"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140098","term_label":"catalytic activity, acting on RNA","supporting_discovery_ids":[1,2,3,5,8,10]},{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[0,2,3,9]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[2,3,4]},{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[3]},{"term_id":"GO:0005840","term_label":"ribosome","supporting_discovery_ids":[3,8]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[3,4,5,8,10]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[5,8]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[6]}],"complexes":["SLBP-ERI1-stem-loop RNA ternary complex","Lsm1-7-ERI1 complex"],"partners":["SLBP","LSM1","TUT7","PB2","PB1","NP"],"other_free_text":[]},"mechanistic_narrative":"ERI1 (3'hExo) is a conserved 3'-to-5' DEDDh-family exoribonuclease that plays dual housekeeping roles in ribosomal RNA maturation and replication-dependent histone mRNA metabolism, while also modulating small RNA abundance in immune cells. Its nuclease domain employs a binuclear metal cluster (D134, E136, D234, D298, H293) for hydrolytic 3'-to-5' RNA cleavage, while its SAP domain and flanking residues mediate RNA stem-loop recognition and cooperative ternary complex formation with SLBP on histone mRNA, limiting trimming to two unpaired nucleotides under steady-state conditions [PMID:15451662, PMID:23329046]. ERI1 catalyzes the final 3' trimming step of 5.8S rRNA on ribosomes across species, and upon oligouridylation of histone mRNAs by TUT7, ERI1 is recruited via Lsm1-7 to degrade the stem-loop in a stepwise manner, initiating replication-dependent histone mRNA decay [PMID:18438418, PMID:23202588, PMID:36041871]. Loss-of-function ERI1 missense variants cause spondyloepimetaphyseal dysplasia through defective 5.8S rRNA trimming and impaired histone mRNA degradation, with consequent failure of chondrogenic differentiation [PMID:37352860]."},"prefetch_data":{"uniprot":{"accession":"Q8IV48","full_name":"3'-5' exoribonuclease 1","aliases":["3'-5' exonuclease ERI1","Eri-1 homolog","Histone mRNA 3'-end-specific exoribonuclease","Histone mRNA 3'-exonuclease 1","Protein 3'hExo","HEXO"],"length_aa":349,"mass_kda":40.1,"function":"RNA exonuclease that binds to the 3'-end of histone mRNAs and degrades them, suggesting that it plays an essential role in histone mRNA decay after replication (PubMed:14536070, PubMed:16912046, PubMed:17135487, PubMed:37352860). A 2' and 3'-hydroxyl groups at the last nucleotide of the histone 3'-end is required for efficient 3'-end histone mRNA exonuclease activity and degradation of RNA substrates (PubMed:14536070, PubMed:16912046, PubMed:17135487). Also able to degrade the 3'-overhangs of short interfering RNAs (siRNAs) in vitro, suggesting a possible role as regulator of RNA interference (RNAi) (PubMed:14961122). Required for binding the 5'-ACCCA-3' sequence present in stem-loop structure (PubMed:14536070, PubMed:16912046). Able to bind other mRNAs (PubMed:14536070, PubMed:16912046). Required for 5.8S rRNA 3'-end processing (PubMed:37352860). Also binds to 5.8s ribosomal RNA (By similarity). Binds with high affinity to the stem-loop structure of replication-dependent histone pre-mRNAs (PubMed:14536070, PubMed:16912046, PubMed:17135487). In vitro, does not have sequence specificity (PubMed:17135487). In vitro, has weak DNA exonuclease activity (PubMed:17135487). In vitro, shows biphasic kinetics such that there is rapid hydrolysis of the last three unpaired RNA nucleotides in the 39 flanking sequence followed by a much slower cleavage through the stem that occurs over a longer incubation period in the order of hours (PubMed:17135487). ERI1-mediated RNA metabolism plays a key role in chondrogenesis (PubMed:37352860)","subcellular_location":"Cytoplasm; Nucleus; Nucleus, nucleolus","url":"https://www.uniprot.org/uniprotkb/Q8IV48/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ERI1","classification":"Not Classified","n_dependent_lines":22,"n_total_lines":1208,"dependency_fraction":0.018211920529801324},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"DRG1","stoichiometry":0.2},{"gene":"EIF3G","stoichiometry":0.2},{"gene":"RACK1","stoichiometry":0.2},{"gene":"RPS16","stoichiometry":0.2},{"gene":"SRP68","stoichiometry":0.2},{"gene":"SSB","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/ERI1","total_profiled":1310},"omim":[{"mim_id":"620663","title":"SPONDYLOEPIMETAPHYSEAL DYSPLASIA, GUO-CAMPEAU TYPE; SEMDGC","url":"https://www.omim.org/entry/620663"},{"mim_id":"620662","title":"HOXHA-ALIU SYNDROME; HXAL","url":"https://www.omim.org/entry/620662"},{"mim_id":"609917","title":"ERI1 EXORIBONUCLEASE FAMILY MEMBER 3; ERI3","url":"https://www.omim.org/entry/609917"},{"mim_id":"608739","title":"EXORIBONUCLEASE 1; ERI1","url":"https://www.omim.org/entry/608739"},{"mim_id":"602422","title":"STEM-LOOP BINDING PROTEIN; SLBP","url":"https://www.omim.org/entry/602422"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Microtubules","reliability":"Approved"},{"location":"Vesicles","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/ERI1"},"hgnc":{"alias_symbol":["3'HEXO"],"prev_symbol":["THEX1"]},"alphafold":{"accession":"Q8IV48","domains":[{"cath_id":"1.10.720.30","chopping":"63-116","consensus_level":"high","plddt":95.1144,"start":63,"end":116},{"cath_id":"3.30.420.10","chopping":"128-328","consensus_level":"high","plddt":98.205,"start":128,"end":328}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8IV48","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8IV48-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8IV48-F1-predicted_aligned_error_v6.png","plddt_mean":85.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ERI1","jax_strain_url":"https://www.jax.org/strain/search?query=ERI1"},"sequence":{"accession":"Q8IV48","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8IV48.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8IV48/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8IV48"}},"corpus_meta":[{"pmid":"23329046","id":"PMC_23329046","title":"Structure of histone mRNA stem-loop, human stem-loop binding protein, and 3'hExo ternary complex.","date":"2013","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/23329046","citation_count":102,"is_preprint":false},{"pmid":"23202588","id":"PMC_23202588","title":"Eri1 degrades the stem-loop of oligouridylated histone mRNAs to induce replication-dependent decay.","date":"2012","source":"Nature structural & molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/23202588","citation_count":65,"is_preprint":false},{"pmid":"18438419","id":"PMC_18438419","title":"The exonuclease ERI-1 has a conserved dual role in 5.8S rRNA processing and RNAi.","date":"2008","source":"Nature structural & molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/18438419","citation_count":59,"is_preprint":false},{"pmid":"22613798","id":"PMC_22613798","title":"Eri1 regulates microRNA homeostasis and mouse lymphocyte development and antiviral 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Part A","url":"https://pubmed.ncbi.nlm.nih.gov/28488351","citation_count":10,"is_preprint":false},{"pmid":"32960265","id":"PMC_32960265","title":"Influenza A virus co-opts ERI1 exonuclease bound to histone mRNA to promote viral transcription.","date":"2020","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/32960265","citation_count":7,"is_preprint":false},{"pmid":"27966489","id":"PMC_27966489","title":"Reserpine requires the D2-type receptor, dop-3, and the exoribonuclease, eri-1, to extend the lifespan in C. elegans.","date":"2016","source":"Journal of biosciences","url":"https://pubmed.ncbi.nlm.nih.gov/27966489","citation_count":6,"is_preprint":false},{"pmid":"17658462","id":"PMC_17658462","title":"esiRNA to eri-1 and adar-1 genes improving high doses of c-myc-directed esiRNA effect on mouse melanoma growth inhibition.","date":"2007","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/17658462","citation_count":6,"is_preprint":false},{"pmid":"27531275","id":"PMC_27531275","title":"ERIL1, the plant homologue of ERI-1, is involved in the processing of chloroplastic rRNAs.","date":"2016","source":"The Plant journal : for cell and molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/27531275","citation_count":5,"is_preprint":false},{"pmid":"24475317","id":"PMC_24475317","title":"A pre- and co-knockdown of RNAseT enzyme, Eri-1, enhances the efficiency of RNAi induced gene silencing in Caenorhabditis elegans.","date":"2014","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/24475317","citation_count":4,"is_preprint":false},{"pmid":"27617966","id":"PMC_27617966","title":"Anti-Ephrin Type-B Receptor 2 (EphB2) and Anti-Three Prime Histone mRNA EXonuclease 1 (THEX1) Autoantibodies in Scleroderma and Lupus.","date":"2016","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/27617966","citation_count":4,"is_preprint":false},{"pmid":"37352860","id":"PMC_37352860","title":"Null and missense mutations of ERI1 cause a recessive phenotypic dichotomy in humans.","date":"2023","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/37352860","citation_count":3,"is_preprint":false},{"pmid":"36041871","id":"PMC_36041871","title":"Knockouts of TUT7 and 3'hExo show that they cooperate in histone mRNA maintenance and degradation.","date":"2022","source":"RNA (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/36041871","citation_count":3,"is_preprint":false},{"pmid":"36208065","id":"PMC_36208065","title":"ERI1: A case report of an autosomal recessive syndrome associated with developmental delay and distal limb abnormalities.","date":"2022","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/36208065","citation_count":3,"is_preprint":false},{"pmid":"28626879","id":"PMC_28626879","title":"Snipper, an Eri1 homologue, affects histone mRNA abundance and is crucial for normal Drosophila melanogaster development.","date":"2017","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/28626879","citation_count":2,"is_preprint":false},{"pmid":"39119676","id":"PMC_39119676","title":"The ER-Resident Ras Inhibitor 1 (Eri1) of Candida albicans Inhibits Hyphal Morphogenesis via the Ras-Independent cAMP-PKA Pathway.","date":"2024","source":"ACS infectious diseases","url":"https://pubmed.ncbi.nlm.nih.gov/39119676","citation_count":1,"is_preprint":false},{"pmid":"39945916","id":"PMC_39945916","title":"Congenital Bone Disorders Associated with ERI1-Mediated RNA Metabolism Dysfunction: Spondylo-Epi-Metaphyseal Dysplasia Guo-Campeau Type and Beyond.","date":"2025","source":"Current osteoporosis reports","url":"https://pubmed.ncbi.nlm.nih.gov/39945916","citation_count":0,"is_preprint":false},{"pmid":"37516934","id":"PMC_37516934","title":"Uridylation of the histone mRNA stem-loop weakens binding interactions with SLBP while maintaining interactions with 3'hExo.","date":"2023","source":"RNA biology","url":"https://pubmed.ncbi.nlm.nih.gov/37516934","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.11.29.24318222","title":"Genetic Evidence for Soluble VEGFR2 as a Protective Factor Against Macular Pucker","date":"2024-11-30","source":"bioRxiv","url":"https://doi.org/10.1101/2024.11.29.24318222","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.04.11.25325582","title":"Genome-wide association study and multi-ancestry meta-analysis identify common variants associated with carotid artery intima-media thickness","date":"2025-04-14","source":"bioRxiv","url":"https://doi.org/10.1101/2025.04.11.25325582","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":13899,"output_tokens":3351,"usd":0.045981},"stage2":{"model":"claude-opus-4-6","input_tokens":6721,"output_tokens":2974,"usd":0.161933},"total_usd":0.207914,"stage1_batch_id":"msgbatch_0118RScg3WGaGkaZRtWZbtce","stage2_batch_id":"msgbatch_01Cpfzvtbj42aqp5oYZ5Te2s","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2013,\n      \"finding\": \"Crystal structure of the ternary complex of human SLBP RNA binding domain, human 3'hExo (ERI1), and a 26-nucleotide stem-loop RNA revealed that only one base of the stem-loop is recognized specifically by SLBP, both proteins primarily recognize RNA shape, SLBP and 3'hExo have no direct protein-protein contact, and induced structural changes in the loop mediate cooperative binding; the 3' flanking sequence is positioned in the 3'hExo active site but the ternary complex limits the extent of trimming.\",\n      \"method\": \"X-ray crystallography of ternary complex\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure at atomic resolution with functional validation of cooperative binding mechanism\",\n      \"pmids\": [\"23329046\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Crystal structure of the nuclease domain of 3'hExo (ERI1) bound to rAMP with Mg2+ showed it adopts a DEDDh family alpha/beta fold with a binuclear metal cluster coordinated by D134, E136, D234, D298, and H293 acting as general base for hydrolytic RNA cleavage in the 3'→5' direction; the 2'-OH and 3'-OH groups of the substrate are required for efficient degradation.\",\n      \"method\": \"X-ray crystallography at 1.6 Å resolution; mutagenesis and in vitro exonuclease assays\",\n      \"journal\": \"Journal of Molecular Biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — atomic resolution structure with active site characterization and biochemical validation\",\n      \"pmids\": [\"15451662\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"3'hExo (ERI1) specifically binds the 3' stem-loop of histone mRNA via its SAP domain and two lysines C-terminal to it; catalytic activity requires the DEDDh active site residues; 3'hExo trims 3' overhangs of siRNAs but cannot degrade double-stranded regions; it localizes predominantly to the cytoplasm and has only residual activity on DNA substrates.\",\n      \"method\": \"Site-directed mutagenesis, in vitro RNA binding and exonuclease assays, subcellular fractionation/localization\",\n      \"journal\": \"Journal of Biological Chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — mutagenesis dissecting RNA binding vs. catalytic residues with orthogonal biochemical assays\",\n      \"pmids\": [\"16912046\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Mouse Eri1 associates with ribosomes and ribosomal RNA, and catalyzes the final 3' end trimming step of 5.8S rRNA; catalytically inactive Eri1 mutant fails to rescue aberrant 5.8S rRNA extension in Eri1-deficient cells; RNA binding via the SAP and linker domains promotes stable rRNA association and facilitates processing; Eri1 localizes to cytoplasm and nucleolus.\",\n      \"method\": \"Ribosome co-sedimentation, in vitro rRNA processing assay with wild-type vs. catalytic mutant, subcellular localization (immunofluorescence), rescue experiments in Eri1-deficient cells\",\n      \"journal\": \"Nature Structural & Molecular Biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal methods including in vitro reconstitution, catalytic mutant, and cellular rescue\",\n      \"pmids\": [\"18438418\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"ERI-1 performs 3' end processing of 5.8S rRNA in both C. elegans and S. pombe, and two protein isoforms of C. elegans ERI-1 localize to the cytoplasm with distinct functions in rRNA processing and negative regulation of RNA interference.\",\n      \"method\": \"Genetic analysis in C. elegans and S. pombe, isoform characterization, subcellular localization\",\n      \"journal\": \"Nature Structural & Molecular Biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic and biochemical evidence replicated across two organisms\",\n      \"pmids\": [\"18438419\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Eri1 degrades the stem-loop of oligouridylated histone mRNAs to initiate replication-dependent decay: Eri1 trims mature histone mRNAs by two unpaired nucleotides at the 3' end but stalls at the double-stranded stem; upon oligouridylation, the Lsm1-7 heteroheptamer recognizes the oligo(U) tail and interacts with Eri1, enabling Eri1's catalytic activity to degrade the stem-loop in a stepwise manner. Eri1-deficient mouse cells accumulate oligouridylated histone mRNAs with impaired degradation.\",\n      \"method\": \"Eri1-deficient mouse cell analysis, RNA sequencing, Co-IP of Lsm1-7 with Eri1, in vitro RNA degradation assays, mutagenesis\",\n      \"journal\": \"Nature Structural & Molecular Biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal methods, KO cells with specific molecular phenotype plus biochemical reconstitution of stepwise degradation\",\n      \"pmids\": [\"23202588\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Eri1 regulates miRNA homeostasis in mouse lymphocytes; Eri1-deficient NK and T cells display a global, sequence-independent increase in miRNA abundance; ectopic Eri1 expression rescues defective miRNA expression in mature Eri1-deficient T cells. Eri1 deficiency causes cell-intrinsic defects in NK-cell development and Ly49 receptor acquisition.\",\n      \"method\": \"Eri1 knockout mouse, small RNA profiling, reconstitution by ectopic expression, flow cytometry for NK cell phenotype\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — KO mouse with defined molecular phenotype, rescue experiment, multiple cell types\",\n      \"pmids\": [\"22613798\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Fission yeast Eri1 specifically degrades double-stranded siRNAs through two functional domains, represses accumulation of cellular siRNAs in vivo, and deletion of eri1+ increases siRNAs associated with the RITS complex, enhancing heterochromatic silencing with increased H3-K9 methylation and Swi6 protein levels.\",\n      \"method\": \"Eri1 deletion in S. pombe, siRNA quantification, ChIP for H3-K9 methylation and Swi6, in vitro dsRNA degradation assays\",\n      \"journal\": \"Current Biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — genetic deletion with defined chromatin phenotype plus biochemical activity assay\",\n      \"pmids\": [\"16797182\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"3'hExo (ERI1) is essential for initiating histone mRNA degradation on polyribosomes at the 3' side of the stem-loop; 3'hExo cooperates with TUT7 (TENT3B/ZCCHC6) to both maintain histone mRNA length during S-phase and degrade it at S-phase end; knockout of 3'hExo prevents initiation of 3'→5' degradation and stabilizes histone mRNA, while TUT7 knockout prevents uridylation of degradation intermediates slowing degradation.\",\n      \"method\": \"CRISPR knockout of TUT7 and 3'hExo in human cells, synchronized cell analysis, RNA sequencing of degradation intermediates\",\n      \"journal\": \"RNA\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO of two factors with defined molecular phenotypes and epistatic relationship established\",\n      \"pmids\": [\"36041871\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"ERI1 interacts with the PB2, PB1, and NP components of influenza A viral ribonucleoproteins in an RNA-dependent manner, and both the RNA binding and exonuclease activities of ERI1 are required to promote influenza A virus mRNA transcription; during infection, SLBP and histone mRNAs co-purify with vRNPs alongside ERI1, suggesting ERI1 is recruited as part of the histone pre-mRNA processing complex in the nucleus.\",\n      \"method\": \"Interactomics/Co-IP, siRNA silencing, viral transcription assay, ERI1 activity mutants\",\n      \"journal\": \"Nucleic Acids Research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — Co-IP plus functional mutagenesis showing both activities required, but single lab\",\n      \"pmids\": [\"32960265\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"ERI1 missense variants identified in patients with spondyloepimetaphyseal dysplasia cause loss of exoribonuclease activity, leading to defective trimming of the 5.8S rRNA 3' end and decreased degradation of replication-dependent histone mRNAs; patient-derived iPSCs showed impaired in vitro chondrogenesis with downregulation of skeletal patterning genes.\",\n      \"method\": \"Patient-derived cells, in vitro 5.8S rRNA processing assay, histone mRNA degradation assay, iPSC chondrogenesis differentiation\",\n      \"journal\": \"American Journal of Human Genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — biochemical activity assays on patient variants plus iPSC differentiation model with defined molecular phenotypes\",\n      \"pmids\": [\"37352860\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Uridylation of the histone mRNA stem-loop weakens binding interactions with SLBP while maintaining interactions with 3'hExo (ERI1); uridylation allows 3'hExo to maintain contact with the stem-loop after partial degradation and disrupts key base pairs in partially degraded histone mRNA intermediates.\",\n      \"method\": \"Fluorescence polarization, EMSA, 1-µs molecular dynamics simulations\",\n      \"journal\": \"RNA Biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — biophysical binding assays with computational support, single lab\",\n      \"pmids\": [\"37516934\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Drosophila Snipper (ERI1 homolog) directly interacts with histone mRNA; its depletion causes drastic reduction in histone transcript levels, suggesting Snp protects histone mRNA 3'-ends from degradation; Snp perturbation leads to larval arrest and tissue-specific developmental abnormalities.\",\n      \"method\": \"RNA immunoprecipitation, RNAi knockdown, developmental phenotype analysis in Drosophila\",\n      \"journal\": \"FEBS Letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — direct binding shown by RIP with KD phenotype, but ortholog with distinct behavior from 3'hExo\",\n      \"pmids\": [\"28626879\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ERI1 (3'hExo) is a conserved 3'-to-5' DEDDh-family exoribonuclease that: (1) catalyzes the final trimming step of 5.8S rRNA 3' ends by associating with ribosomes via its SAP and linker domains; (2) binds the conserved stem-loop of histone mRNAs through its SAP domain and cooperates with SLBP in a ternary complex to trim histone mRNA 3' ends by two nucleotides; (3) upon oligouridylation of histone mRNA by TUT7, is recruited via Lsm1-7 interaction to degrade the stem-loop in a stepwise manner, initiating replication-dependent histone mRNA decay; and (4) degrades siRNAs to negatively regulate RNAi and miRNA abundance in lymphocytes, linking it to immune cell development and antiviral function.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ERI1 (3'hExo) is a conserved 3'-to-5' DEDDh-family exoribonuclease that plays dual housekeeping roles in ribosomal RNA maturation and replication-dependent histone mRNA metabolism, while also modulating small RNA abundance in immune cells. Its nuclease domain employs a binuclear metal cluster (D134, E136, D234, D298, H293) for hydrolytic 3'-to-5' RNA cleavage, while its SAP domain and flanking residues mediate RNA stem-loop recognition and cooperative ternary complex formation with SLBP on histone mRNA, limiting trimming to two unpaired nucleotides under steady-state conditions [PMID:15451662, PMID:23329046]. ERI1 catalyzes the final 3' trimming step of 5.8S rRNA on ribosomes across species, and upon oligouridylation of histone mRNAs by TUT7, ERI1 is recruited via Lsm1-7 to degrade the stem-loop in a stepwise manner, initiating replication-dependent histone mRNA decay [PMID:18438418, PMID:23202588, PMID:36041871]. Loss-of-function ERI1 missense variants cause spondyloepimetaphyseal dysplasia through defective 5.8S rRNA trimming and impaired histone mRNA degradation, with consequent failure of chondrogenic differentiation [PMID:37352860].\",\n  \"teleology\": [\n    {\n      \"year\": 2004,\n      \"claim\": \"Determination of the catalytic mechanism: the crystal structure of the ERI1 nuclease domain revealed a DEDDh-family exoribonuclease fold with a binuclear metal active site, establishing the chemical basis for 3'-to-5' hydrolytic RNA cleavage and the requirement for 2'-OH and 3'-OH groups.\",\n      \"evidence\": \"1.6 Å X-ray crystal structure with bound rAMP and Mg²⁺, validated by mutagenesis and in vitro exonuclease assays\",\n      \"pmids\": [\"15451662\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structural information yet on the SAP domain or full-length protein\", \"Physiological RNA substrates not yet identified\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Identification of substrate specificity and RNA-binding determinants: ERI1's SAP domain and C-terminal lysines mediate specific binding to the histone mRNA stem-loop, while the enzyme trims siRNA 3' overhangs but cannot degrade double-stranded RNA, defining its substrate scope.\",\n      \"evidence\": \"Site-directed mutagenesis separating RNA-binding from catalytic residues, in vitro binding and nuclease assays, subcellular fractionation\",\n      \"pmids\": [\"16912046\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How ERI1 is recruited to substrates in vivo remained unknown\", \"No in vivo demonstration of siRNA degradation in mammalian cells\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Discovery of ERI1 as a negative regulator of RNAi and heterochromatic silencing: fission yeast Eri1 degrades double-stranded siRNAs, and its deletion enhances siRNA accumulation, RITS complex loading, H3-K9 methylation, and heterochromatic gene silencing.\",\n      \"evidence\": \"S. pombe eri1Δ, siRNA quantification, ChIP for H3-K9me and Swi6, in vitro dsRNA degradation\",\n      \"pmids\": [\"16797182\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether mammalian ERI1 similarly regulates heterochromatic siRNA pathways was untested\", \"Mechanism of dsRNA access by ERI1 in vivo unclear\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Establishing ERI1 as the terminal 5.8S rRNA processing enzyme: mouse and C. elegans/S. pombe studies converged to show ERI1 catalyzes the final 3' trimming of 5.8S rRNA on ribosomes, with the SAP/linker domains mediating ribosome association, revealing a conserved housekeeping function.\",\n      \"evidence\": \"Ribosome co-sedimentation, in vitro rRNA processing with catalytic mutants, rescue in Eri1-deficient cells, cross-species genetics\",\n      \"pmids\": [\"18438418\", \"18438419\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of ERI1–ribosome interaction not resolved\", \"Whether 5.8S rRNA processing defects have physiological consequences in mammals was unclear\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Mechanistic dissection of histone mRNA decay initiation: ERI1 trims two nucleotides from mature histone mRNA but stalls at the stem; upon oligouridylation, Lsm1-7 recognizes the oligo(U) tail and facilitates ERI1's stepwise degradation of the stem-loop, establishing ERI1 as the enzyme that initiates 3'-to-5' histone mRNA degradation.\",\n      \"evidence\": \"Eri1-deficient mouse cells accumulating oligouridylated histone mRNAs, Co-IP of Lsm1-7 with Eri1, in vitro reconstitution of stepwise degradation\",\n      \"pmids\": [\"23202588\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How Lsm1-7 activates ERI1 catalytically on the stem-loop was structurally unresolved\", \"Downstream 3'-to-5' degradation machinery after stem-loop removal not identified\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Demonstrating ERI1's role in miRNA homeostasis and immune cell development: Eri1-deficient mouse NK and T cells show global miRNA upregulation, and Eri1 deficiency causes cell-intrinsic NK cell developmental defects, linking ERI1's exonuclease activity to immune regulation.\",\n      \"evidence\": \"Eri1 knockout mouse, small RNA profiling, ectopic expression rescue, flow cytometry for NK cell phenotyping\",\n      \"pmids\": [\"22613798\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether ERI1 directly degrades mature miRNAs or acts on precursors was not resolved\", \"Mechanism of sequence-independent miRNA regulation unclear\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Structural basis of cooperative ternary complex formation: the crystal structure of SLBP–ERI1–stem-loop RNA showed that SLBP and ERI1 lack direct protein-protein contact and instead cooperate through induced RNA conformational changes, explaining how the complex limits trimming to two nucleotides.\",\n      \"evidence\": \"X-ray crystallography of the ternary complex with functional validation\",\n      \"pmids\": [\"23329046\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How uridylation disrupts this cooperative complex to permit further degradation was not structurally captured\", \"No dynamic or kinetic data on complex assembly/disassembly\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Epistatic relationship between ERI1 and TUT7 in histone mRNA turnover: CRISPR knockouts showed ERI1 is essential for initiating 3'-side degradation on polyribosomes, while TUT7 uridylates intermediates to sustain degradation, establishing the ordered enzymatic logic of histone mRNA decay.\",\n      \"evidence\": \"CRISPR KO of ERI1 and TUT7 in human cells, synchronized cell cycle analysis, sequencing of degradation intermediates\",\n      \"pmids\": [\"36041871\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether additional nucleases act redundantly with ERI1 in histone mRNA decay was not fully excluded\", \"Polyribosome context of decay not structurally resolved\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Uridylation differentially modulates SLBP and ERI1 binding: uridylation of histone mRNA weakens SLBP binding while maintaining ERI1 contact, providing a biophysical mechanism for the switch from steady-state trimming to processive degradation.\",\n      \"evidence\": \"Fluorescence polarization, EMSA, and molecular dynamics simulations\",\n      \"pmids\": [\"37516934\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Computational predictions not yet validated by structural experiments\", \"Single-lab study without independent replication\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Human disease causation established: loss-of-function ERI1 missense variants cause spondyloepimetaphyseal dysplasia through impaired 5.8S rRNA trimming and histone mRNA degradation, with defective chondrogenesis in patient-derived iPSCs.\",\n      \"evidence\": \"Patient-derived cells, in vitro 5.8S rRNA and histone mRNA processing assays, iPSC chondrogenesis differentiation\",\n      \"pmids\": [\"37352860\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the skeletal phenotype is driven primarily by rRNA or histone mRNA defects is unresolved\", \"No animal model recapitulating the human skeletal phenotype reported\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include: the structural basis of ERI1's interaction with ribosomes during 5.8S rRNA processing, the mechanism by which Lsm1-7 activates ERI1 to degrade the stem-loop, whether ERI1 directly degrades mature miRNAs or acts on precursor forms, and the relative contributions of impaired rRNA versus histone mRNA processing to the skeletal dysplasia phenotype.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No full-length ERI1 structure on the ribosome\", \"Lsm1-7 activation mechanism structurally unresolved\", \"Direct vs. indirect miRNA regulation not distinguished\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140098\", \"supporting_discovery_ids\": [1, 2, 3, 5, 8, 10]},\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [0, 2, 3, 9]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [2, 3, 4]},\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"GO:0005840\", \"supporting_discovery_ids\": [3, 8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [3, 4, 5, 8, 10]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [5, 8]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"complexes\": [\n      \"SLBP-ERI1-stem-loop RNA ternary complex\",\n      \"Lsm1-7-ERI1 complex\"\n    ],\n    \"partners\": [\n      \"SLBP\",\n      \"LSM1\",\n      \"TUT7\",\n      \"PB2\",\n      \"PB1\",\n      \"NP\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}