{"gene":"UTP3","run_date":"2026-06-11T09:02:06","timeline":{"discoveries":[{"year":2019,"finding":"Sas10/Utp3 protects Mpp10 from Capn3-mediated cleavage by masking the Capn3-recognition site on Mpp10, thereby stabilizing Mpp10 in the nucleolus. Sas10 also determines the nucleolar localization of the Mpp10-Imp3-Imp4 complex, acting as a delivery factor for SSU processome assembly.","method":"Zebrafish genetics (loss-of-function), co-immunoprecipitation, subcellular localization experiments, protein stability/degradation assays","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, loss-of-function in zebrafish with defined molecular phenotypes, multiple orthogonal methods in a single rigorous study","pmids":["30773582"],"is_preprint":false},{"year":2024,"finding":"UTP3/SAS10 autonomously enters the nucleolus and facilitates nucleolar localization of five SSU processome components (MPP10, UTP25, EMG1, UTP12, UTP13) through its interaction with nuclear importin α ('ferrying' function). Knockdown of human UTP3 impairs A0-site cleavage in pre-rRNA 5'ETS processing, and UTP3 facilitates degradation of processed 5'ETS by recruiting RNA exosome component EXOSC10 to the nucleolus.","method":"Systematic nucleolar localization screen of 50 human SSU processome components, siRNA knockdown, interaction with importin α, EXOSC10 recruitment assay, zebrafish loss-of-function validation","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (localization screen, knockdown with functional readout, importin interaction, exosome recruitment), replicated in zebrafish","pmids":["39036955"],"is_preprint":false},{"year":2022,"finding":"E3 ligase TRIM29 mediates ubiquitination-dependent degradation of UTP3; the lncRNA HCP5 interacts with UTP3 and prevents this TRIM29-mediated ubiquitination, thereby stabilizing UTP3 protein levels.","method":"Co-immunoprecipitation, ubiquitination assay, lncRNA-protein interaction assay, RNA immunoprecipitation","journal":"Molecular therapy : the journal of the American Society of Gene Therapy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP and ubiquitination assays in a single lab with multiple methods, but no mutagenesis or structural validation","pmids":["36245126"],"is_preprint":false},{"year":2022,"finding":"UTP3 recruits c-Myc to activate VAMP3 transcription; stabilized UTP3 (via HCP5-mediated protection from TRIM29 ubiquitination) leads to VAMP3-dependent suppression of caspase-dependent apoptosis.","method":"Chromatin immunoprecipitation, co-immunoprecipitation, reporter assay, knockdown/overexpression functional assays","journal":"Molecular therapy : the journal of the American Society of Gene Therapy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and Co-IP with functional apoptosis readout, single lab, multiple methods","pmids":["36245126"],"is_preprint":false},{"year":2009,"finding":"Crlz-1 (UTP3/SAS10) mobilizes cytoplasmic CBFβ into the nucleus, where it forms a ternary complex with nuclear Runx/CBFβ heterodimer bound to its target DNA (IgJ enhancer), activating CBF-dependent transcription.","method":"Co-transfection reporter assay, co-immunoprecipitation, chromatin immunoprecipitation, fluorescence localization","journal":"Biochimica et biophysica acta","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP, ChIP, functional reporter assay, single lab","pmids":["19735751"],"is_preprint":false},{"year":2016,"finding":"Crlz-1 (UTP3) acts as a Wnt target gene in pre-B cells, relaying Wnt/β-catenin signaling to pre-B cell receptor signaling by mobilizing cytoplasmic CBFβ into the nucleus for Runx/CBFβ heterodimerization, which activates VpreB and λ5 expression and drives cyclin D2/D3 expression and proliferation.","method":"siRNA knockdown, overexpression, Wnt pathway inhibitors/activators (niclosamide, XAV939, LiCl), reporter assay, flow cytometry","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function and pharmacological intervention with defined proliferative phenotype, single lab, multiple approaches","pmids":["27226553"],"is_preprint":false},{"year":2019,"finding":"Crlz-1 (UTP3) in centroblasts relays Wnt/β-catenin signaling to Bcl-6 expression by mobilizing cytoplasmic CBFβ into the nucleus, enabling Runx/CBFβ heterodimerization and binding to the Bcl-6 promoter, thereby sustaining germinal center reaction.","method":"Crlz-1/β-catenin knockdown, Wnt inhibitor treatment in immunized mice, ChIP on Bcl-6 promoter, in vivo germinal center assay","journal":"Journal of immunology (Baltimore, Md. : 1950)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo knockdown and pharmacological experiments with defined molecular and cellular phenotype, ChIP validation, single lab","pmids":["31586036"],"is_preprint":false},{"year":2025,"finding":"The nuclear localization signal of Crlz-1 (UTP3) maps to a short KRAI sequence; peptides mimicking this sequence block Crlz-1 nuclear translocation, prevent CBFβ nuclear mobilization, abolish Runx/CBFβ binding to the Bcl-6 promoter, and decrease rRNA production in germinal center B cells.","method":"NLS mapping, peptide inhibition, reporter assay, chromatin immunoprecipitation, rRNA quantification, xenograft mouse model","journal":"Molecular therapy. Oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct NLS mapping with functional peptide inhibition, ChIP, rRNA assay, in vivo validation, single lab","pmids":["40093512"],"is_preprint":false},{"year":2010,"finding":"The Sas10/C1D domain (present in UTP3/SAS10) is predicted to be alpha-helical (~80 residues) and proposed to form a binding surface for protein-protein interactions while concomitantly interacting with RNA or DNA, facilitating docking of partner proteins onto nucleic acid substrates.","method":"Bioinformatic/structural prediction and literature synthesis (no direct experimental characterization of the domain itself reported)","journal":"Biochemical Society transactions","confidence":"Low","confidence_rationale":"Tier 4 / Weak — computational/predictive analysis only, no experimental validation of domain function described in this abstract","pmids":["20659009"],"is_preprint":false}],"current_model":"UTP3/SAS10 (CRLZ1) is a multifunctional nucleolar protein that (1) autonomously localizes to the nucleolus via importin α and ferries five SSU processome components (MPP10, UTP25, EMG1, UTP12, UTP13) to the nucleolus for ribosomal small subunit processome assembly; (2) stabilizes Mpp10 by masking its Capn3-cleavage site; (3) recruits RNA exosome component EXOSC10 to facilitate 5'ETS degradation and is required for A0-site pre-rRNA cleavage; (4) in B cells, mobilizes cytoplasmic CBFβ into the nucleus to enable Runx/CBFβ heterodimerization and transcriptional activation of target genes (VpreB, λ5, Bcl-6) downstream of Wnt/β-catenin signaling; and (5) is itself regulated by TRIM29-mediated ubiquitination and proteasomal degradation, which can be blocked by the lncRNA HCP5."},"narrative":{"mechanistic_narrative":"UTP3/SAS10 (CRLZ1) is a multifunctional nucleolar protein that acts as a delivery and assembly factor for the small subunit (SSU) processome during ribosomal biogenesis [PMID:39036955]. It autonomously enters the nucleolus through interaction with importin α and ferries multiple SSU processome components — MPP10, UTP25, EMG1, UTP12, and UTP13 — into the nucleolus, where it is required for A0-site cleavage during pre-rRNA 5'ETS processing and recruits the RNA exosome component EXOSC10 to drive degradation of the processed 5'ETS [PMID:39036955]. UTP3 specifically stabilizes Mpp10 by masking its Capn3-cleavage site and determines nucleolar localization of the Mpp10–Imp3–Imp4 complex [PMID:30773582]. A short KRAI nuclear localization signal mediates its nuclear translocation, and peptides mimicking this sequence block both its rRNA-promoting activity and its transcriptional functions [PMID:40093512]. Beyond ribosome biogenesis, UTP3 couples Wnt/β-catenin signaling to B-cell transcriptional programs: as a Wnt target gene it mobilizes cytoplasmic CBFβ into the nucleus to enable Runx/CBFβ heterodimer formation on target promoters, activating VpreB and λ5 in pre-B cells and sustaining Bcl-6 expression and the germinal center reaction in centroblasts [PMID:27226553, PMID:31586036, PMID:19735751]. UTP3 protein levels are controlled by TRIM29-mediated ubiquitination and proteasomal degradation, which the lncRNA HCP5 antagonizes by binding and stabilizing UTP3; stabilized UTP3 recruits c-Myc to activate VAMP3 transcription and suppress caspase-dependent apoptosis [PMID:36245126].","teleology":[{"year":2009,"claim":"Established that UTP3/Crlz-1 has a transcriptional role distinct from ribosome biogenesis by acting as a shuttling factor that controls CBFβ subcellular distribution.","evidence":"Co-transfection reporter assay, reciprocal Co-IP, ChIP and fluorescence localization in B-cell context","pmids":["19735751"],"confidence":"Medium","gaps":["Mechanism of CBFβ mobilization at molecular detail not resolved","Did not connect to upstream signaling inputs"]},{"year":2016,"claim":"Placed UTP3/Crlz-1 as a Wnt/β-catenin target gene that relays Wnt signaling to pre-B cell receptor gene expression and proliferation, answering how an upstream pathway engages the CBFβ-mobilization function.","evidence":"siRNA knockdown, overexpression, Wnt pharmacological modulators, reporter and flow cytometry in pre-B cells","pmids":["27226553"],"confidence":"Medium","gaps":["Direct β-catenin occupancy on the UTP3 locus not characterized in this entry","Mechanism linking CBFβ nuclear entry to cyclin D2/D3 not fully resolved"]},{"year":2019,"claim":"Defined the ribosome-biogenesis function by showing UTP3/Sas10 stabilizes Mpp10 against Capn3 cleavage and delivers the Mpp10-Imp3-Imp4 complex to the nucleolus, establishing it as an SSU processome assembly factor.","evidence":"Zebrafish loss-of-function, reciprocal Co-IP, localization and protein stability assays","pmids":["30773582"],"confidence":"High","gaps":["Did not enumerate the full set of cargo proteins delivered","Did not map the Capn3 site or the masking interface structurally"]},{"year":2019,"claim":"Extended the Wnt-CBFβ axis to germinal center centroblasts, showing UTP3 sustains Bcl-6 expression and the germinal center reaction in vivo.","evidence":"Crlz-1/β-catenin knockdown, Wnt inhibitor treatment in immunized mice, ChIP on Bcl-6 promoter, in vivo germinal center assay","pmids":["31586036"],"confidence":"Medium","gaps":["Whether ribosome-biogenesis function contributes to germinal center phenotype not separated","Direct versus indirect Bcl-6 regulation not fully dissected"]},{"year":2022,"claim":"Identified the post-translational control of UTP3 abundance, showing TRIM29 ubiquitinates UTP3 for degradation while lncRNA HCP5 binds and protects it, and linked stabilized UTP3 to c-Myc-driven VAMP3 transcription and apoptosis suppression.","evidence":"Co-IP, ubiquitination assay, lncRNA-protein and RNA immunoprecipitation, ChIP, reporter and apoptosis functional assays (single lab)","pmids":["36245126"],"confidence":"Medium","gaps":["No mutagenesis of ubiquitination sites or structural validation of HCP5-UTP3 interface","c-Myc recruitment mechanism by UTP3 not defined"]},{"year":2024,"claim":"Generalized the delivery function by demonstrating importin-α-dependent autonomous nucleolar entry and ferrying of five SSU processome components, plus a direct role in A0-site cleavage and EXOSC10-mediated 5'ETS degradation.","evidence":"Systematic nucleolar localization screen, siRNA knockdown with pre-rRNA processing readout, importin α interaction, EXOSC10 recruitment assay, zebrafish validation","pmids":["39036955"],"confidence":"High","gaps":["Structural basis of cargo selection not resolved","How A0 cleavage and exosome recruitment are mechanistically coordinated unknown"]},{"year":2025,"claim":"Mapped the nuclear localization signal to a short KRAI sequence and demonstrated that blocking it disrupts both transcriptional (CBFβ/Bcl-6) and ribosomal (rRNA production) functions, unifying the dual roles under a single trafficking determinant.","evidence":"NLS mapping, peptide inhibition, reporter assay, ChIP, rRNA quantification, xenograft mouse model","pmids":["40093512"],"confidence":"Medium","gaps":["Whether the same KRAI motif governs importin-α nucleolar entry not directly linked","Therapeutic peptide specificity not fully characterized"]},{"year":null,"claim":"How UTP3 partitions between its nucleolar ribosome-biogenesis role and its CBFβ-mobilizing transcriptional role within the same cell, and what dictates this switch, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of the Sas10/C1D domain interactions","Mechanism coordinating cargo ferrying versus CBFβ shuttling unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140098","term_label":"catalytic activity, acting on RNA","supporting_discovery_ids":[1]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[4,5,6]}],"localization":[{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[0,1]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[4,7]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[0,1]},{"term_id":"R-HSA-1852241","term_label":"Organelle biogenesis and maintenance","supporting_discovery_ids":[1]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[4,5,6]}],"complexes":["SSU processome"],"partners":["MPP10","EMG1","UTP25","UTP12","UTP13","EXOSC10","CBFB","TRIM29"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9NQZ2","full_name":"Something about silencing protein 10","aliases":["Charged amino acid-rich leucine zipper 1","CRL1","Disrupter of silencing SAS10","UTP3 homolog"],"length_aa":479,"mass_kda":54.6,"function":"Essential for gene silencing: has a role in the structure of silenced chromatin. Plays a role in the developing brain (By similarity). Part of the small subunit (SSU) processome, first precursor of the small eukaryotic ribosomal subunit. During the assembly of the SSU processome in the nucleolus, many ribosome biogenesis factors, an RNA chaperone and ribosomal proteins associate with the nascent pre-rRNA and work in concert to generate RNA folding, modifications, rearrangements and cleavage as well as targeted degradation of pre-ribosomal RNA by the RNA exosome (PubMed:34516797)","subcellular_location":"Nucleus, nucleolus","url":"https://www.uniprot.org/uniprotkb/Q9NQZ2/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/UTP3","classification":"Common Essential","n_dependent_lines":1037,"n_total_lines":1208,"dependency_fraction":0.8584437086092715},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"MPHOSPH10","stoichiometry":10.0},{"gene":"CSNK2B","stoichiometry":0.2},{"gene":"IMP3","stoichiometry":0.2},{"gene":"NPM1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/UTP3","total_profiled":1310},"omim":[{"mim_id":"611614","title":"UTP3 SMALL SUBUNIT PROCESSOME COMPONENT; UTP3","url":"https://www.omim.org/entry/611614"},{"mim_id":"147790","title":"JOINING CHAIN OF MULTIMERIC IgA AND IgM; JCHAIN","url":"https://www.omim.org/entry/147790"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoli","reliability":"Supported"},{"location":"Vesicles","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/UTP3"},"hgnc":{"alias_symbol":["FLJ23256","DKFZp761F222","SAS10","CRLZ1"],"prev_symbol":[]},"alphafold":{"accession":"Q9NQZ2","domains":[{"cath_id":"1.20.120","chopping":"225-338","consensus_level":"high","plddt":83.1016,"start":225,"end":338}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NQZ2","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NQZ2-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NQZ2-F1-predicted_aligned_error_v6.png","plddt_mean":68.12},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=UTP3","jax_strain_url":"https://www.jax.org/strain/search?query=UTP3"},"sequence":{"accession":"Q9NQZ2","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9NQZ2.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9NQZ2/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NQZ2"}},"corpus_meta":[{"pmid":"12756328","id":"PMC_12756328","title":"RNA editing and regulation of Drosophila 4f-rnp expression by sas-10 antisense readthrough mRNA transcripts.","date":"2003","source":"RNA (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/12756328","citation_count":65,"is_preprint":false},{"pmid":"36245126","id":"PMC_36245126","title":"HCP5 prevents ubiquitination-mediated UTP3 degradation to inhibit apoptosis by activating c-Myc transcriptional activity.","date":"2022","source":"Molecular therapy : the journal of the American Society of Gene Therapy","url":"https://pubmed.ncbi.nlm.nih.gov/36245126","citation_count":35,"is_preprint":false},{"pmid":"30773582","id":"PMC_30773582","title":"Sas10 controls ribosome biogenesis by stabilizing Mpp10 and delivering the Mpp10-Imp3-Imp4 complex to nucleolus.","date":"2019","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/30773582","citation_count":28,"is_preprint":false},{"pmid":"20659009","id":"PMC_20659009","title":"Rrp47 and the function of the Sas10/C1D domain.","date":"2010","source":"Biochemical Society transactions","url":"https://pubmed.ncbi.nlm.nih.gov/20659009","citation_count":18,"is_preprint":false},{"pmid":"17015728","id":"PMC_17015728","title":"Stage-specific expression of two neighboring Crlz1 and IgJ genes during B cell development is regulated by their chromatin accessibility and histone acetylation.","date":"2006","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/17015728","citation_count":15,"is_preprint":false},{"pmid":"21544627","id":"PMC_21544627","title":"A strong promoter activity of pre-B cell stage-specific Crlz1 gene is caused by one distal LEF-1 and multiple proximal Ets sites.","date":"2011","source":"Molecules and cells","url":"https://pubmed.ncbi.nlm.nih.gov/21544627","citation_count":8,"is_preprint":false},{"pmid":"19735751","id":"PMC_19735751","title":"Crlz1 activates transcription by mobilizing cytoplasmic CBFbeta into the nucleus.","date":"2009","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/19735751","citation_count":7,"is_preprint":false},{"pmid":"27226553","id":"PMC_27226553","title":"Charged Amino Acid-rich Leucine Zipper-1 (Crlz-1) as a Target of Wnt Signaling Pathway Controls Pre-B Cell Proliferation by Affecting Runx/CBFβ-targeted VpreB and λ5 Genes.","date":"2016","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/27226553","citation_count":7,"is_preprint":false},{"pmid":"16962668","id":"PMC_16962668","title":"The HSS3/4 enhancer of Crlz1-IgJ locus is another target of EBF in the pre-B cell stage of B cell development.","date":"2006","source":"Immunology letters","url":"https://pubmed.ncbi.nlm.nih.gov/16962668","citation_count":4,"is_preprint":false},{"pmid":"39036955","id":"PMC_39036955","title":"A UTP3-dependent nucleolar translocation pathway facilitates pre-rRNA 5'ETS processing.","date":"2024","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/39036955","citation_count":3,"is_preprint":false},{"pmid":"31586036","id":"PMC_31586036","title":"Crlz-1 Controls Germinal Center Reaction by Relaying a Wnt Signal to the Bcl-6 Expression in Centroblasts during Humoral Immune Responses.","date":"2019","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/31586036","citation_count":3,"is_preprint":false},{"pmid":"23525569","id":"PMC_23525569","title":"Crlz-1 is prominently expressed in spermatogonia and Sertoli cells during early testis development and in spermatids during late spermatogenesis.","date":"2013","source":"The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society","url":"https://pubmed.ncbi.nlm.nih.gov/23525569","citation_count":3,"is_preprint":false},{"pmid":"35328065","id":"PMC_35328065","title":"Crlz-1 Homozygous Null Knockout Mouse Embryos Are Lethally Stopped in Their Early Development.","date":"2022","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/35328065","citation_count":1,"is_preprint":false},{"pmid":"42157077","id":"PMC_42157077","title":"A conserved Sas10/C1D domain protein, CaLrp1, is a critical regulator of hyphal development and pathogenicity in Candida albicans.","date":"2026","source":"BMC microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/42157077","citation_count":0,"is_preprint":false},{"pmid":"41465602","id":"PMC_41465602","title":"The Nuclear Effector RIRG190 Interacts with SAS10 to Regulate Arbuscular Mycorrhizal Symbiosis.","date":"2025","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/41465602","citation_count":0,"is_preprint":false},{"pmid":"40093512","id":"PMC_40093512","title":"Anti-lymphoma peptide is inspired by mapping a sequence of four amino acids of KRAI motif as nuclear localization signal of Crlz-1.","date":"2025","source":"Molecular therapy. Oncology","url":"https://pubmed.ncbi.nlm.nih.gov/40093512","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9358,"output_tokens":2415,"usd":0.032149,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9600,"output_tokens":3035,"usd":0.061937,"stage2_stop_reason":"end_turn"},"total_usd":0.094086,"stage1_batch_id":"msgbatch_01UT1AahFPCAyn2uVweS7A9z","stage2_batch_id":"msgbatch_01HuKWtKNT4Pqj1bc8eEP5RV","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2019,\n      \"finding\": \"Sas10/Utp3 protects Mpp10 from Capn3-mediated cleavage by masking the Capn3-recognition site on Mpp10, thereby stabilizing Mpp10 in the nucleolus. Sas10 also determines the nucleolar localization of the Mpp10-Imp3-Imp4 complex, acting as a delivery factor for SSU processome assembly.\",\n      \"method\": \"Zebrafish genetics (loss-of-function), co-immunoprecipitation, subcellular localization experiments, protein stability/degradation assays\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, loss-of-function in zebrafish with defined molecular phenotypes, multiple orthogonal methods in a single rigorous study\",\n      \"pmids\": [\"30773582\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"UTP3/SAS10 autonomously enters the nucleolus and facilitates nucleolar localization of five SSU processome components (MPP10, UTP25, EMG1, UTP12, UTP13) through its interaction with nuclear importin α ('ferrying' function). Knockdown of human UTP3 impairs A0-site cleavage in pre-rRNA 5'ETS processing, and UTP3 facilitates degradation of processed 5'ETS by recruiting RNA exosome component EXOSC10 to the nucleolus.\",\n      \"method\": \"Systematic nucleolar localization screen of 50 human SSU processome components, siRNA knockdown, interaction with importin α, EXOSC10 recruitment assay, zebrafish loss-of-function validation\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (localization screen, knockdown with functional readout, importin interaction, exosome recruitment), replicated in zebrafish\",\n      \"pmids\": [\"39036955\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"E3 ligase TRIM29 mediates ubiquitination-dependent degradation of UTP3; the lncRNA HCP5 interacts with UTP3 and prevents this TRIM29-mediated ubiquitination, thereby stabilizing UTP3 protein levels.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, lncRNA-protein interaction assay, RNA immunoprecipitation\",\n      \"journal\": \"Molecular therapy : the journal of the American Society of Gene Therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP and ubiquitination assays in a single lab with multiple methods, but no mutagenesis or structural validation\",\n      \"pmids\": [\"36245126\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"UTP3 recruits c-Myc to activate VAMP3 transcription; stabilized UTP3 (via HCP5-mediated protection from TRIM29 ubiquitination) leads to VAMP3-dependent suppression of caspase-dependent apoptosis.\",\n      \"method\": \"Chromatin immunoprecipitation, co-immunoprecipitation, reporter assay, knockdown/overexpression functional assays\",\n      \"journal\": \"Molecular therapy : the journal of the American Society of Gene Therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and Co-IP with functional apoptosis readout, single lab, multiple methods\",\n      \"pmids\": [\"36245126\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Crlz-1 (UTP3/SAS10) mobilizes cytoplasmic CBFβ into the nucleus, where it forms a ternary complex with nuclear Runx/CBFβ heterodimer bound to its target DNA (IgJ enhancer), activating CBF-dependent transcription.\",\n      \"method\": \"Co-transfection reporter assay, co-immunoprecipitation, chromatin immunoprecipitation, fluorescence localization\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP, ChIP, functional reporter assay, single lab\",\n      \"pmids\": [\"19735751\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Crlz-1 (UTP3) acts as a Wnt target gene in pre-B cells, relaying Wnt/β-catenin signaling to pre-B cell receptor signaling by mobilizing cytoplasmic CBFβ into the nucleus for Runx/CBFβ heterodimerization, which activates VpreB and λ5 expression and drives cyclin D2/D3 expression and proliferation.\",\n      \"method\": \"siRNA knockdown, overexpression, Wnt pathway inhibitors/activators (niclosamide, XAV939, LiCl), reporter assay, flow cytometry\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function and pharmacological intervention with defined proliferative phenotype, single lab, multiple approaches\",\n      \"pmids\": [\"27226553\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Crlz-1 (UTP3) in centroblasts relays Wnt/β-catenin signaling to Bcl-6 expression by mobilizing cytoplasmic CBFβ into the nucleus, enabling Runx/CBFβ heterodimerization and binding to the Bcl-6 promoter, thereby sustaining germinal center reaction.\",\n      \"method\": \"Crlz-1/β-catenin knockdown, Wnt inhibitor treatment in immunized mice, ChIP on Bcl-6 promoter, in vivo germinal center assay\",\n      \"journal\": \"Journal of immunology (Baltimore, Md. : 1950)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo knockdown and pharmacological experiments with defined molecular and cellular phenotype, ChIP validation, single lab\",\n      \"pmids\": [\"31586036\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"The nuclear localization signal of Crlz-1 (UTP3) maps to a short KRAI sequence; peptides mimicking this sequence block Crlz-1 nuclear translocation, prevent CBFβ nuclear mobilization, abolish Runx/CBFβ binding to the Bcl-6 promoter, and decrease rRNA production in germinal center B cells.\",\n      \"method\": \"NLS mapping, peptide inhibition, reporter assay, chromatin immunoprecipitation, rRNA quantification, xenograft mouse model\",\n      \"journal\": \"Molecular therapy. Oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct NLS mapping with functional peptide inhibition, ChIP, rRNA assay, in vivo validation, single lab\",\n      \"pmids\": [\"40093512\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"The Sas10/C1D domain (present in UTP3/SAS10) is predicted to be alpha-helical (~80 residues) and proposed to form a binding surface for protein-protein interactions while concomitantly interacting with RNA or DNA, facilitating docking of partner proteins onto nucleic acid substrates.\",\n      \"method\": \"Bioinformatic/structural prediction and literature synthesis (no direct experimental characterization of the domain itself reported)\",\n      \"journal\": \"Biochemical Society transactions\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — computational/predictive analysis only, no experimental validation of domain function described in this abstract\",\n      \"pmids\": [\"20659009\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"UTP3/SAS10 (CRLZ1) is a multifunctional nucleolar protein that (1) autonomously localizes to the nucleolus via importin α and ferries five SSU processome components (MPP10, UTP25, EMG1, UTP12, UTP13) to the nucleolus for ribosomal small subunit processome assembly; (2) stabilizes Mpp10 by masking its Capn3-cleavage site; (3) recruits RNA exosome component EXOSC10 to facilitate 5'ETS degradation and is required for A0-site pre-rRNA cleavage; (4) in B cells, mobilizes cytoplasmic CBFβ into the nucleus to enable Runx/CBFβ heterodimerization and transcriptional activation of target genes (VpreB, λ5, Bcl-6) downstream of Wnt/β-catenin signaling; and (5) is itself regulated by TRIM29-mediated ubiquitination and proteasomal degradation, which can be blocked by the lncRNA HCP5.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"UTP3/SAS10 (CRLZ1) is a multifunctional nucleolar protein that acts as a delivery and assembly factor for the small subunit (SSU) processome during ribosomal biogenesis [#1]. It autonomously enters the nucleolus through interaction with importin α and ferries multiple SSU processome components — MPP10, UTP25, EMG1, UTP12, and UTP13 — into the nucleolus, where it is required for A0-site cleavage during pre-rRNA 5'ETS processing and recruits the RNA exosome component EXOSC10 to drive degradation of the processed 5'ETS [#1]. UTP3 specifically stabilizes Mpp10 by masking its Capn3-cleavage site and determines nucleolar localization of the Mpp10–Imp3–Imp4 complex [#0]. A short KRAI nuclear localization signal mediates its nuclear translocation, and peptides mimicking this sequence block both its rRNA-promoting activity and its transcriptional functions [#7]. Beyond ribosome biogenesis, UTP3 couples Wnt/β-catenin signaling to B-cell transcriptional programs: as a Wnt target gene it mobilizes cytoplasmic CBFβ into the nucleus to enable Runx/CBFβ heterodimer formation on target promoters, activating VpreB and λ5 in pre-B cells and sustaining Bcl-6 expression and the germinal center reaction in centroblasts [#5, #6, #4]. UTP3 protein levels are controlled by TRIM29-mediated ubiquitination and proteasomal degradation, which the lncRNA HCP5 antagonizes by binding and stabilizing UTP3; stabilized UTP3 recruits c-Myc to activate VAMP3 transcription and suppress caspase-dependent apoptosis [#2, #3].\",\n  \"teleology\": [\n    {\n      \"year\": 2009,\n      \"claim\": \"Established that UTP3/Crlz-1 has a transcriptional role distinct from ribosome biogenesis by acting as a shuttling factor that controls CBFβ subcellular distribution.\",\n      \"evidence\": \"Co-transfection reporter assay, reciprocal Co-IP, ChIP and fluorescence localization in B-cell context\",\n      \"pmids\": [\"19735751\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of CBFβ mobilization at molecular detail not resolved\", \"Did not connect to upstream signaling inputs\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Placed UTP3/Crlz-1 as a Wnt/β-catenin target gene that relays Wnt signaling to pre-B cell receptor gene expression and proliferation, answering how an upstream pathway engages the CBFβ-mobilization function.\",\n      \"evidence\": \"siRNA knockdown, overexpression, Wnt pharmacological modulators, reporter and flow cytometry in pre-B cells\",\n      \"pmids\": [\"27226553\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct β-catenin occupancy on the UTP3 locus not characterized in this entry\", \"Mechanism linking CBFβ nuclear entry to cyclin D2/D3 not fully resolved\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Defined the ribosome-biogenesis function by showing UTP3/Sas10 stabilizes Mpp10 against Capn3 cleavage and delivers the Mpp10-Imp3-Imp4 complex to the nucleolus, establishing it as an SSU processome assembly factor.\",\n      \"evidence\": \"Zebrafish loss-of-function, reciprocal Co-IP, localization and protein stability assays\",\n      \"pmids\": [\"30773582\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not enumerate the full set of cargo proteins delivered\", \"Did not map the Capn3 site or the masking interface structurally\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Extended the Wnt-CBFβ axis to germinal center centroblasts, showing UTP3 sustains Bcl-6 expression and the germinal center reaction in vivo.\",\n      \"evidence\": \"Crlz-1/β-catenin knockdown, Wnt inhibitor treatment in immunized mice, ChIP on Bcl-6 promoter, in vivo germinal center assay\",\n      \"pmids\": [\"31586036\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether ribosome-biogenesis function contributes to germinal center phenotype not separated\", \"Direct versus indirect Bcl-6 regulation not fully dissected\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identified the post-translational control of UTP3 abundance, showing TRIM29 ubiquitinates UTP3 for degradation while lncRNA HCP5 binds and protects it, and linked stabilized UTP3 to c-Myc-driven VAMP3 transcription and apoptosis suppression.\",\n      \"evidence\": \"Co-IP, ubiquitination assay, lncRNA-protein and RNA immunoprecipitation, ChIP, reporter and apoptosis functional assays (single lab)\",\n      \"pmids\": [\"36245126\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No mutagenesis of ubiquitination sites or structural validation of HCP5-UTP3 interface\", \"c-Myc recruitment mechanism by UTP3 not defined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Generalized the delivery function by demonstrating importin-α-dependent autonomous nucleolar entry and ferrying of five SSU processome components, plus a direct role in A0-site cleavage and EXOSC10-mediated 5'ETS degradation.\",\n      \"evidence\": \"Systematic nucleolar localization screen, siRNA knockdown with pre-rRNA processing readout, importin α interaction, EXOSC10 recruitment assay, zebrafish validation\",\n      \"pmids\": [\"39036955\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of cargo selection not resolved\", \"How A0 cleavage and exosome recruitment are mechanistically coordinated unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Mapped the nuclear localization signal to a short KRAI sequence and demonstrated that blocking it disrupts both transcriptional (CBFβ/Bcl-6) and ribosomal (rRNA production) functions, unifying the dual roles under a single trafficking determinant.\",\n      \"evidence\": \"NLS mapping, peptide inhibition, reporter assay, ChIP, rRNA quantification, xenograft mouse model\",\n      \"pmids\": [\"40093512\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether the same KRAI motif governs importin-α nucleolar entry not directly linked\", \"Therapeutic peptide specificity not fully characterized\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How UTP3 partitions between its nucleolar ribosome-biogenesis role and its CBFβ-mobilizing transcriptional role within the same cell, and what dictates this switch, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of the Sas10/C1D domain interactions\", \"Mechanism coordinating cargo ferrying versus CBFβ shuttling unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140098\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [4, 5, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [4, 7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [4, 5, 6]}\n    ],\n    \"complexes\": [\"SSU processome\"],\n    \"partners\": [\"MPP10\", \"EMG1\", \"UTP25\", \"UTP12\", \"UTP13\", \"EXOSC10\", \"CBFB\", \"TRIM29\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":6,"faith_pct":66.66666666666667}}