{"gene":"BYSL","run_date":"2026-06-09T22:02:45","timeline":{"discoveries":[{"year":1997,"finding":"Yeast Enp1 protein (ortholog of human BYSL) is localized to the nucleus, as demonstrated by immunohistochemical studies using a c-myc-tagged fusion construct.","method":"Immunohistochemistry with epitope-tagged protein (c-myc fusion)","journal":"Gene","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — single localization experiment with tagged protein, replicated in concept by later yeast and mammalian studies","pmids":["9034325"],"is_preprint":false},{"year":2003,"finding":"Yeast Enp1 is required for early pre-rRNA processing at sites A0, A1, and A2, and for synthesis of 20S pre-rRNA and 18S rRNA, leading to reduced 40S ribosomal subunit formation. Enp1 co-precipitates with Nop1 protein and with U3 and U14 snoRNAs, placing it in the early pre-rRNA processing machinery.","method":"Northern blot analysis of rRNA precursors in temperature-sensitive enp1-1 mutant; pulse-chase analysis; co-precipitation assay","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (northern blot, pulse-chase, co-precipitation) in single study; findings mechanistically consistent with mammalian BYSL function established by later work","pmids":["12527778"],"is_preprint":false},{"year":2003,"finding":"Yeast Enp1 is concentrated in the nucleolus, consistent with its role in ribosome biogenesis.","method":"Subcellular localization by co-precipitation and inferred from nucleolar protein Nop1 association","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — localization inferred from association with nucleolar marker Nop1; single lab","pmids":["12527778"],"is_preprint":false},{"year":2006,"finding":"Targeted disruption of the mouse Bysl gene results in embryonic lethality shortly after implantation, establishing that bystin is essential for post-implantation mouse embryo survival. Bystin expression was detected in uterine epithelia at peri-implantation stages and in blastocysts.","method":"Gene knockout (targeted disruption) in mouse; immunolocalization","journal":"FEBS letters","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic knockout with defined lethal phenotype, replicated by independent siRNA study (PMID:17242206)","pmids":["17055491"],"is_preprint":false},{"year":2007,"finding":"Mammalian Bysl (bystin-like) is an integral factor for 40S ribosomal subunit biogenesis. Loss of Bysl function via siRNA or dominant-negative mutants caused defects in 40S ribosomal subunit biogenesis. Exogenously expressed Bysl is concentrated in the nucleolus with diffuse nucleoplasmic distribution.","method":"siRNA knockdown; dominant-negative mutants; fluorescent protein tagging and live-cell imaging; 40S subunit biogenesis assay","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (RNAi, dominant-negative, localization, ribosome biogenesis assay) in single study; consistent with yeast ortholog data","pmids":["17242206"],"is_preprint":false},{"year":2007,"finding":"Bysl siRNA knockdown in mouse preimplantation embryos arrests development just prior to blastocyst formation, resulting in a defect in trophectoderm differentiation, establishing Bysl as essential for this developmental transition.","method":"siRNA injection into embryos; developmental staging","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct loss-of-function with specific developmental phenotype, consistent with Bysl knockout lethality (PMID:17055491)","pmids":["17242206"],"is_preprint":false},{"year":2020,"finding":"BYSL promotes glioblastoma cell migration, invasion, and epithelial-mesenchymal transition (EMT) via the GSK-3β/β-catenin signaling pathway. BYSL overexpression increased phosphorylation of GSK-3β and nuclear distribution of β-catenin; GSK-3β inhibition partially reversed the effects of BYSL downregulation on β-catenin transcriptional activity and EMT markers.","method":"siRNA knockdown and overexpression in GBM cell lines; Western blot for EMT markers (β-catenin, N-cadherin, E-cadherin); pharmacological inhibition of GSK-3β (1-Azakenpaullone); nuclear fractionation; immunohistochemistry","journal":"Frontiers in oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KD/OE with pathway rescue experiment in single lab; pathway placement via pharmacological inhibitor","pmids":["33178594"],"is_preprint":false},{"year":2021,"finding":"BYSL forms a complex with RIOK2 and mTOR (mTORC2 complex components), and co-localizes with RIOK2 in glioma cells. Overexpression of BYSL or RIOK2 increased AKT/mTOR signaling activity, while knockdown decreased it, placing BYSL as a positive regulator of AKT/mTOR signaling through its association with RIOK2 and mTOR.","method":"Co-immunoprecipitation; double immunofluorescence co-localization; Western blot for AKT/mTOR signaling; overexpression and siRNA knockdown; orthotopic xenograft model","journal":"Cancer biology & medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP with co-localization and functional validation, single lab","pmids":["33628587"],"is_preprint":false},{"year":2022,"finding":"miR-378a-3p directly binds to the 3'-UTR of BYSL mRNA and suppresses BYSL expression, establishing BYSL as a direct target of miR-378a-3p. BYSL upregulation under hypoxia enhanced Nrf2 expression in osteosarcoma cells.","method":"Dual-luciferase reporter assay; rescue assay; Western blot","journal":"Frontiers in genetics","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — dual-luciferase reporter with rescue assay confirms direct miRNA-target relationship, single lab","pmids":["35154253"],"is_preprint":false},{"year":2026,"finding":"BYSL knockdown in AML cell lines inhibits cell proliferation, reduces colony-forming ability, and induces G0/G1 cell cycle arrest. Mechanistically, BYSL suppression decreases PI3K and AKT phosphorylation. ChIP-qPCR confirmed that c-MYC directly binds to the BYSL promoter, establishing BYSL as a transcriptional target of c-MYC.","method":"shRNA knockdown in AML cell lines; Western blot for PI3K/AKT phosphorylation; ChIP-qPCR; cell cycle analysis; colony formation assay","journal":"Clinical and experimental medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP-qPCR for transcriptional regulation plus functional KD with pathway analysis; single lab, single study","pmids":["41854887"],"is_preprint":false}],"current_model":"BYSL (bystin-like) encodes a nucleolar protein that is an essential and conserved factor for 40S ribosomal subunit biogenesis — functioning in early pre-rRNA processing (sites A0/A1/A2) in association with U3/U14 snoRNAs and Nop1 — and is required for mouse preimplantation development and trophectoderm differentiation; in cancer contexts, BYSL promotes cell proliferation and invasiveness through association with RIOK2/mTOR complexes (activating AKT/mTOR signaling) and through the GSK-3β/β-catenin pathway, and is transcriptionally regulated by c-MYC."},"narrative":{"mechanistic_narrative":"BYSL (bystin-like) is a conserved nucleolar factor for small (40S) ribosomal subunit biogenesis, acting at the earliest steps of pre-rRNA processing [PMID:12527778, PMID:17242206]. Studies of the yeast ortholog Enp1 established that the protein is required for pre-rRNA cleavage at sites A0, A1, and A2 and for production of 20S pre-rRNA and 18S rRNA, and that it co-precipitates with the nucleolar protein Nop1 and with U3 and U14 snoRNAs, embedding it in the early processing machinery [PMID:12527778]; the protein concentrates in the nucleus and nucleolus [PMID:9034325, PMID:12527778]. The mammalian protein is likewise an integral 40S biogenesis factor whose loss disrupts subunit formation, and it localizes to the nucleolus with diffuse nucleoplasmic distribution [PMID:17242206]. This essential housekeeping role is reflected developmentally: targeted disruption of mouse Bysl causes peri-implantation embryonic lethality [PMID:17055491], and Bysl knockdown arrests preimplantation embryos before blastocyst formation with defective trophectoderm differentiation [PMID:17242206]. In cancer contexts BYSL is co-opted as a pro-proliferative, pro-invasive factor: it forms a complex with RIOK2 and mTOR and positively regulates AKT/mTOR signaling [PMID:33628587], drives EMT through GSK-3β/β-catenin signaling in glioblastoma [PMID:33178594], and supports proliferation and PI3K/AKT activity in AML, where it is a direct transcriptional target of c-MYC [PMID:41854887]. BYSL expression is additionally controlled post-transcriptionally by direct binding of miR-378a-3p to its 3'-UTR [PMID:35154253].","teleology":[{"year":1997,"claim":"Establishing where the protein acts: the yeast ortholog Enp1 was localized to the nucleus, providing the first subcellular framing for its function.","evidence":"Immunohistochemistry of a c-myc-tagged Enp1 fusion in yeast","pmids":["9034325"],"confidence":"Medium","gaps":["Localization based on a tagged construct in a single study","No molecular function assigned at this stage","Nucleolar versus broader nuclear residence not resolved"]},{"year":2003,"claim":"Defining molecular function: Enp1 was shown to be required for early pre-rRNA processing and to physically associate with the snoRNP machinery, placing it directly in 40S subunit biogenesis.","evidence":"Northern blot and pulse-chase of rRNA precursors in temperature-sensitive enp1-1 mutant plus co-precipitation with Nop1 and U3/U14 snoRNAs; nucleolar localization inferred","pmids":["12527778"],"confidence":"High","gaps":["Whether the association with snoRNAs is direct or indirect not resolved","Stoichiometry and structural arrangement within the processing complex unknown","Demonstrated in yeast; conservation to mammals not yet tested"]},{"year":2006,"claim":"Testing organismal requirement: mouse Bysl knockout established that the gene is essential, with embryonic lethality shortly after implantation.","evidence":"Targeted gene disruption in mouse with immunolocalization in peri-implantation tissues","pmids":["17055491"],"confidence":"High","gaps":["Knockout phenotype not yet mechanistically tied to ribosome biogenesis defect","Cell-type-specific contributions not dissected"]},{"year":2007,"claim":"Connecting mammalian function and development: mammalian Bysl was confirmed as an integral 40S biogenesis factor, and its knockdown blocked preimplantation development at trophectoderm differentiation, linking ribosome biogenesis to a specific developmental transition.","evidence":"siRNA, dominant-negative mutants, fluorescent tagging, and 40S biogenesis assays in cells; siRNA injection and developmental staging in mouse embryos","pmids":["17242206"],"confidence":"High","gaps":["Precise biochemical step catalyzed by mammalian Bysl not defined","Whether trophectoderm defect is solely a consequence of impaired ribosome biogenesis not established"]},{"year":2020,"claim":"Identifying a disease-context signaling role: BYSL was shown to promote glioblastoma migration, invasion, and EMT via GSK-3β/β-catenin signaling.","evidence":"siRNA/overexpression in GBM cell lines, EMT-marker Western blots, pharmacological GSK-3β inhibition, nuclear fractionation, and immunohistochemistry","pmids":["33178594"],"confidence":"Medium","gaps":["Pathway placement relies on a pharmacological inhibitor","Direct molecular link between BYSL and GSK-3β not demonstrated","Single lab, single tumor type"]},{"year":2021,"claim":"Defining a physical signaling partner: BYSL was found to complex with RIOK2 and mTOR and to positively regulate AKT/mTOR signaling in glioma.","evidence":"Reciprocal Co-IP, double immunofluorescence co-localization, AKT/mTOR Western blots, overexpression/knockdown, and orthotopic xenograft","pmids":["33628587"],"confidence":"Medium","gaps":["Direct binary interactions within the BYSL–RIOK2–mTOR complex not resolved","Relationship between this signaling role and the canonical ribosome biogenesis role unclear","Single lab"]},{"year":2022,"claim":"Establishing post-transcriptional control: miR-378a-3p was shown to directly target the BYSL 3'-UTR, and BYSL was linked to Nrf2 induction under hypoxia.","evidence":"Dual-luciferase reporter and rescue assays with Western blot in osteosarcoma cells","pmids":["35154253"],"confidence":"Medium","gaps":["Mechanism linking BYSL to Nrf2 not defined","Single lab, single cancer type"]},{"year":2026,"claim":"Identifying transcriptional control and a proliferative requirement: c-MYC was shown to directly bind the BYSL promoter, and BYSL suppression caused G0/G1 arrest and reduced PI3K/AKT phosphorylation in AML.","evidence":"shRNA knockdown, ChIP-qPCR, cell cycle and colony-formation assays, and PI3K/AKT Western blots in AML cell lines","pmids":["41854887"],"confidence":"Medium","gaps":["Whether PI3K/AKT changes are direct or secondary to reduced ribosome biogenesis not resolved","Single study"]},{"year":null,"claim":"How the conserved nucleolar 40S-biogenesis function mechanistically connects to the AKT/mTOR, GSK-3β/β-catenin, and c-MYC signaling roles reported in cancer remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of BYSL within the pre-rRNA processing machinery in the corpus","Direct binding partners of mammalian BYSL during ribosome biogenesis not enumerated","Causal ordering between ribosome biogenesis defects and signaling outputs not established"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[1]}],"localization":[{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[2,4]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,4]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[1,4]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[6,7]}],"complexes":["mTORC2"],"partners":["NOP1","RIOK2","MTOR"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q13895","full_name":"Bystin","aliases":[],"length_aa":437,"mass_kda":49.6,"function":"Required for processing of 20S pre-rRNA precursor and biogenesis of 40S ribosomal subunits. May be required for trophinin-dependent regulation of cell adhesion during implantation of human embryos","subcellular_location":"Cytoplasm; Nucleus, nucleolus","url":"https://www.uniprot.org/uniprotkb/Q13895/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/BYSL","classification":"Common Essential","n_dependent_lines":1206,"n_total_lines":1208,"dependency_fraction":0.9983443708609272},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000112578","cell_line_id":"CID001082","localizations":[{"compartment":"nucleolus_gc","grade":3},{"compartment":"cytoplasmic","grade":2},{"compartment":"nucleoplasm","grade":1}],"interactors":[{"gene":"PARN","stoichiometry":10.0},{"gene":"PNO1","stoichiometry":10.0},{"gene":"RIOK2","stoichiometry":10.0},{"gene":"LTV1","stoichiometry":10.0},{"gene":"NOB1","stoichiometry":10.0},{"gene":"TSR1","stoichiometry":10.0},{"gene":"RRP12","stoichiometry":10.0},{"gene":"FAM207A","stoichiometry":4.0},{"gene":"NOP14","stoichiometry":4.0},{"gene":"FAU","stoichiometry":4.0}],"url":"https://opencell.sf.czbiohub.org/target/CID001082","total_profiled":1310},"omim":[{"mim_id":"620074","title":"LTV1 RIBOSOME BIOGENESIS FACTOR; LTV1","url":"https://www.omim.org/entry/620074"},{"mim_id":"618710","title":"PARTNER OF NOB1; PNO1","url":"https://www.omim.org/entry/618710"},{"mim_id":"617754","title":"RIO KINASE 2; RIOK2","url":"https://www.omim.org/entry/617754"},{"mim_id":"617753","title":"RIO KINASE 1; RIOK1","url":"https://www.omim.org/entry/617753"},{"mim_id":"617723","title":"RIBOSOMAL RNA-PROCESSING 12; RRP12","url":"https://www.omim.org/entry/617723"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Nucleoli","reliability":"Enhanced"},{"location":"Nucleoli rim","reliability":"Enhanced"},{"location":"Mitotic chromosome","reliability":"Enhanced"},{"location":"Nucleoplasm","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/BYSL"},"hgnc":{"alias_symbol":["Enp1"],"prev_symbol":[]},"alphafold":{"accession":"Q13895","domains":[{"cath_id":"-","chopping":"148-154_176-318","consensus_level":"medium","plddt":91.2306,"start":148,"end":318},{"cath_id":"1.25.40","chopping":"320-429","consensus_level":"medium","plddt":94.3386,"start":320,"end":429}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q13895","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q13895-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q13895-F1-predicted_aligned_error_v6.png","plddt_mean":77.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=BYSL","jax_strain_url":"https://www.jax.org/strain/search?query=BYSL"},"sequence":{"accession":"Q13895","fasta_url":"https://rest.uniprot.org/uniprotkb/Q13895.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q13895/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q13895"}},"corpus_meta":[{"pmid":"17557882","id":"PMC_17557882","title":"EnP1, a microsporidian spore wall protein that enables spores to adhere to and infect host cells in vitro.","date":"2007","source":"Eukaryotic cell","url":"https://pubmed.ncbi.nlm.nih.gov/17557882","citation_count":80,"is_preprint":false},{"pmid":"16368098","id":"PMC_16368098","title":"EnP1 and EnP2, two proteins associated with the Encephalitozoon cuniculi endospore, the chitin-rich inner layer of the microsporidian spore wall.","date":"2005","source":"International journal for parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/16368098","citation_count":54,"is_preprint":false},{"pmid":"12527778","id":"PMC_12527778","title":"Enp1, a yeast protein associated with U3 and U14 snoRNAs, is required for pre-rRNA processing and 40S subunit synthesis.","date":"2003","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/12527778","citation_count":53,"is_preprint":false},{"pmid":"16322284","id":"PMC_16322284","title":"Identification of CCND3 and BYSL as candidate targets for the 6p21 amplification in diffuse large B-cell lymphoma.","date":"2005","source":"Clinical cancer research : an official journal of the American Association for Cancer Research","url":"https://pubmed.ncbi.nlm.nih.gov/16322284","citation_count":36,"is_preprint":false},{"pmid":"17242206","id":"PMC_17242206","title":"Crucial role of Bysl in mammalian preimplantation development as an integral factor for 40S ribosome biogenesis.","date":"2007","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/17242206","citation_count":28,"is_preprint":false},{"pmid":"33178594","id":"PMC_33178594","title":"BYSL Promotes Glioblastoma Cell Migration, Invasion, and Mesenchymal Transition Through the GSK-3β/β-Catenin Signaling Pathway.","date":"2020","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/33178594","citation_count":27,"is_preprint":false},{"pmid":"33628587","id":"PMC_33628587","title":"BYSL contributes to tumor growth by cooperating with the mTORC2 complex in gliomas.","date":"2021","source":"Cancer biology & medicine","url":"https://pubmed.ncbi.nlm.nih.gov/33628587","citation_count":27,"is_preprint":false},{"pmid":"9034325","id":"PMC_9034325","title":"ENP1, an essential gene encoding a nuclear protein that is highly conserved from yeast to humans.","date":"1997","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/9034325","citation_count":24,"is_preprint":false},{"pmid":"17055491","id":"PMC_17055491","title":"The Bysl gene product, bystin, is essential for survival of mouse embryos.","date":"2006","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/17055491","citation_count":12,"is_preprint":false},{"pmid":"34797290","id":"PMC_34797290","title":"DDX10 and BYSL as the potential targets of chondrosarcoma and glioma.","date":"2021","source":"Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/34797290","citation_count":9,"is_preprint":false},{"pmid":"39141344","id":"PMC_39141344","title":"Microsporidian EnP1 alters host cell H2B monoubiquitination and prevents ferroptosis facilitating microsporidia survival.","date":"2024","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/39141344","citation_count":8,"is_preprint":false},{"pmid":"35154253","id":"PMC_35154253","title":"Hypoxia-Induced miR-378a-3p Inhibits Osteosarcoma Invasion and Epithelial-to-Mesenchymal Transition via BYSL Regulation.","date":"2022","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/35154253","citation_count":8,"is_preprint":false},{"pmid":"29349722","id":"PMC_29349722","title":"Bystin (BYSL) as a possible marker of severe hypoxic-ischemic changes in neuropathological examination of forensic cases.","date":"2018","source":"Forensic science, medicine, and pathology","url":"https://pubmed.ncbi.nlm.nih.gov/29349722","citation_count":6,"is_preprint":false},{"pmid":"36704911","id":"PMC_36704911","title":"Sarcomatoid renal cell tumor harboring a novel BYSL::TFEB fusion with concurrent TFEB amplification.","date":"2023","source":"Genes, chromosomes & cancer","url":"https://pubmed.ncbi.nlm.nih.gov/36704911","citation_count":3,"is_preprint":false},{"pmid":"41499632","id":"PMC_41499632","title":"EnP1 exploits H2Aub-dependent epigenetic reprogramming to promote microsporidia proliferation in host cells.","date":"2026","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/41499632","citation_count":1,"is_preprint":false},{"pmid":"41854887","id":"PMC_41854887","title":"Investigation of the expression and potential mechanistic role of BYSL in acute myeloid leukemia.","date":"2026","source":"Clinical and experimental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/41854887","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":9399,"output_tokens":2713,"usd":0.034446,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9525,"output_tokens":3061,"usd":0.062075,"stage2_stop_reason":"end_turn"},"total_usd":0.096521,"stage1_batch_id":"msgbatch_0179Z2pxRYBsXi2xADneafRw","stage2_batch_id":"msgbatch_01LaY9ZaVdgjWArcZo9eqQE5","note":"batch pricing = 50% of standard"},"stage1_raw":"I'll analyze each paper carefully, distinguishing between:\n1. Papers about the canonical BYSL/Bystin protein (human/mammalian or yeast ortholog Enp1)\n2. Papers about microsporidian EnP1 (a completely different protein - fungal pathogen spore wall protein, unrelated to the mammalian ribosome biogenesis factor)\n3. Papers about irrelevant topics\n\n**Classification:**\n- Papers [1], [2], [11], [15]: These describe microsporidian (Encephalitozoon cuniculi) EnP1 - a spore wall protein. This is NOT the human BYSL/bystin protein or its yeast ortholog. This is a symbol collision (microsporidian gene named EnP1). EXCLUDE.\n- Paper [3]: Yeast Enp1 (Saccharomyces cerevisiae) - consistent with the mammalian BYSL function (ribosome biogenesis). INCLUDE as ortholog.\n- Paper [8]: Yeast ENP1 - nuclear protein, ortholog. INCLUDE.\n- Papers [4], [6], [7], [9], [5], [12], [13], [14], [16]: Human/mammalian BYSL. INCLUDE mechanistic ones.\n- Paper [10]: Expression/bioinformatics study - no mechanistic findings. EXCLUDE.\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1997,\n      \"finding\": \"Yeast Enp1 protein (ortholog of human BYSL) is localized to the nucleus, as demonstrated by immunohistochemical studies using a c-myc-tagged fusion construct.\",\n      \"method\": \"Immunohistochemistry with epitope-tagged protein (c-myc fusion)\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — single localization experiment with tagged protein, replicated in concept by later yeast and mammalian studies\",\n      \"pmids\": [\"9034325\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Yeast Enp1 is required for early pre-rRNA processing at sites A0, A1, and A2, and for synthesis of 20S pre-rRNA and 18S rRNA, leading to reduced 40S ribosomal subunit formation. Enp1 co-precipitates with Nop1 protein and with U3 and U14 snoRNAs, placing it in the early pre-rRNA processing machinery.\",\n      \"method\": \"Northern blot analysis of rRNA precursors in temperature-sensitive enp1-1 mutant; pulse-chase analysis; co-precipitation assay\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (northern blot, pulse-chase, co-precipitation) in single study; findings mechanistically consistent with mammalian BYSL function established by later work\",\n      \"pmids\": [\"12527778\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Yeast Enp1 is concentrated in the nucleolus, consistent with its role in ribosome biogenesis.\",\n      \"method\": \"Subcellular localization by co-precipitation and inferred from nucleolar protein Nop1 association\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — localization inferred from association with nucleolar marker Nop1; single lab\",\n      \"pmids\": [\"12527778\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Targeted disruption of the mouse Bysl gene results in embryonic lethality shortly after implantation, establishing that bystin is essential for post-implantation mouse embryo survival. Bystin expression was detected in uterine epithelia at peri-implantation stages and in blastocysts.\",\n      \"method\": \"Gene knockout (targeted disruption) in mouse; immunolocalization\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic knockout with defined lethal phenotype, replicated by independent siRNA study (PMID:17242206)\",\n      \"pmids\": [\"17055491\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Mammalian Bysl (bystin-like) is an integral factor for 40S ribosomal subunit biogenesis. Loss of Bysl function via siRNA or dominant-negative mutants caused defects in 40S ribosomal subunit biogenesis. Exogenously expressed Bysl is concentrated in the nucleolus with diffuse nucleoplasmic distribution.\",\n      \"method\": \"siRNA knockdown; dominant-negative mutants; fluorescent protein tagging and live-cell imaging; 40S subunit biogenesis assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (RNAi, dominant-negative, localization, ribosome biogenesis assay) in single study; consistent with yeast ortholog data\",\n      \"pmids\": [\"17242206\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Bysl siRNA knockdown in mouse preimplantation embryos arrests development just prior to blastocyst formation, resulting in a defect in trophectoderm differentiation, establishing Bysl as essential for this developmental transition.\",\n      \"method\": \"siRNA injection into embryos; developmental staging\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct loss-of-function with specific developmental phenotype, consistent with Bysl knockout lethality (PMID:17055491)\",\n      \"pmids\": [\"17242206\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"BYSL promotes glioblastoma cell migration, invasion, and epithelial-mesenchymal transition (EMT) via the GSK-3β/β-catenin signaling pathway. BYSL overexpression increased phosphorylation of GSK-3β and nuclear distribution of β-catenin; GSK-3β inhibition partially reversed the effects of BYSL downregulation on β-catenin transcriptional activity and EMT markers.\",\n      \"method\": \"siRNA knockdown and overexpression in GBM cell lines; Western blot for EMT markers (β-catenin, N-cadherin, E-cadherin); pharmacological inhibition of GSK-3β (1-Azakenpaullone); nuclear fractionation; immunohistochemistry\",\n      \"journal\": \"Frontiers in oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KD/OE with pathway rescue experiment in single lab; pathway placement via pharmacological inhibitor\",\n      \"pmids\": [\"33178594\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"BYSL forms a complex with RIOK2 and mTOR (mTORC2 complex components), and co-localizes with RIOK2 in glioma cells. Overexpression of BYSL or RIOK2 increased AKT/mTOR signaling activity, while knockdown decreased it, placing BYSL as a positive regulator of AKT/mTOR signaling through its association with RIOK2 and mTOR.\",\n      \"method\": \"Co-immunoprecipitation; double immunofluorescence co-localization; Western blot for AKT/mTOR signaling; overexpression and siRNA knockdown; orthotopic xenograft model\",\n      \"journal\": \"Cancer biology & medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP with co-localization and functional validation, single lab\",\n      \"pmids\": [\"33628587\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"miR-378a-3p directly binds to the 3'-UTR of BYSL mRNA and suppresses BYSL expression, establishing BYSL as a direct target of miR-378a-3p. BYSL upregulation under hypoxia enhanced Nrf2 expression in osteosarcoma cells.\",\n      \"method\": \"Dual-luciferase reporter assay; rescue assay; Western blot\",\n      \"journal\": \"Frontiers in genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — dual-luciferase reporter with rescue assay confirms direct miRNA-target relationship, single lab\",\n      \"pmids\": [\"35154253\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"BYSL knockdown in AML cell lines inhibits cell proliferation, reduces colony-forming ability, and induces G0/G1 cell cycle arrest. Mechanistically, BYSL suppression decreases PI3K and AKT phosphorylation. ChIP-qPCR confirmed that c-MYC directly binds to the BYSL promoter, establishing BYSL as a transcriptional target of c-MYC.\",\n      \"method\": \"shRNA knockdown in AML cell lines; Western blot for PI3K/AKT phosphorylation; ChIP-qPCR; cell cycle analysis; colony formation assay\",\n      \"journal\": \"Clinical and experimental medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP-qPCR for transcriptional regulation plus functional KD with pathway analysis; single lab, single study\",\n      \"pmids\": [\"41854887\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"BYSL (bystin-like) encodes a nucleolar protein that is an essential and conserved factor for 40S ribosomal subunit biogenesis — functioning in early pre-rRNA processing (sites A0/A1/A2) in association with U3/U14 snoRNAs and Nop1 — and is required for mouse preimplantation development and trophectoderm differentiation; in cancer contexts, BYSL promotes cell proliferation and invasiveness through association with RIOK2/mTOR complexes (activating AKT/mTOR signaling) and through the GSK-3β/β-catenin pathway, and is transcriptionally regulated by c-MYC.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"BYSL (bystin-like) is a conserved nucleolar factor for small (40S) ribosomal subunit biogenesis, acting at the earliest steps of pre-rRNA processing [#1, #4]. Studies of the yeast ortholog Enp1 established that the protein is required for pre-rRNA cleavage at sites A0, A1, and A2 and for production of 20S pre-rRNA and 18S rRNA, and that it co-precipitates with the nucleolar protein Nop1 and with U3 and U14 snoRNAs, embedding it in the early processing machinery [#1]; the protein concentrates in the nucleus and nucleolus [#0, #2]. The mammalian protein is likewise an integral 40S biogenesis factor whose loss disrupts subunit formation, and it localizes to the nucleolus with diffuse nucleoplasmic distribution [#4]. This essential housekeeping role is reflected developmentally: targeted disruption of mouse Bysl causes peri-implantation embryonic lethality [#3], and Bysl knockdown arrests preimplantation embryos before blastocyst formation with defective trophectoderm differentiation [#5]. In cancer contexts BYSL is co-opted as a pro-proliferative, pro-invasive factor: it forms a complex with RIOK2 and mTOR and positively regulates AKT/mTOR signaling [#7], drives EMT through GSK-3\\u03b2/\\u03b2-catenin signaling in glioblastoma [#6], and supports proliferation and PI3K/AKT activity in AML, where it is a direct transcriptional target of c-MYC [#9]. BYSL expression is additionally controlled post-transcriptionally by direct binding of miR-378a-3p to its 3'-UTR [#8].\",\n  \"teleology\": [\n    {\n      \"year\": 1997,\n      \"claim\": \"Establishing where the protein acts: the yeast ortholog Enp1 was localized to the nucleus, providing the first subcellular framing for its function.\",\n      \"evidence\": \"Immunohistochemistry of a c-myc-tagged Enp1 fusion in yeast\",\n      \"pmids\": [\"9034325\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Localization based on a tagged construct in a single study\", \"No molecular function assigned at this stage\", \"Nucleolar versus broader nuclear residence not resolved\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Defining molecular function: Enp1 was shown to be required for early pre-rRNA processing and to physically associate with the snoRNP machinery, placing it directly in 40S subunit biogenesis.\",\n      \"evidence\": \"Northern blot and pulse-chase of rRNA precursors in temperature-sensitive enp1-1 mutant plus co-precipitation with Nop1 and U3/U14 snoRNAs; nucleolar localization inferred\",\n      \"pmids\": [\"12527778\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the association with snoRNAs is direct or indirect not resolved\", \"Stoichiometry and structural arrangement within the processing complex unknown\", \"Demonstrated in yeast; conservation to mammals not yet tested\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Testing organismal requirement: mouse Bysl knockout established that the gene is essential, with embryonic lethality shortly after implantation.\",\n      \"evidence\": \"Targeted gene disruption in mouse with immunolocalization in peri-implantation tissues\",\n      \"pmids\": [\"17055491\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Knockout phenotype not yet mechanistically tied to ribosome biogenesis defect\", \"Cell-type-specific contributions not dissected\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Connecting mammalian function and development: mammalian Bysl was confirmed as an integral 40S biogenesis factor, and its knockdown blocked preimplantation development at trophectoderm differentiation, linking ribosome biogenesis to a specific developmental transition.\",\n      \"evidence\": \"siRNA, dominant-negative mutants, fluorescent tagging, and 40S biogenesis assays in cells; siRNA injection and developmental staging in mouse embryos\",\n      \"pmids\": [\"17242206\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Precise biochemical step catalyzed by mammalian Bysl not defined\", \"Whether trophectoderm defect is solely a consequence of impaired ribosome biogenesis not established\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Identifying a disease-context signaling role: BYSL was shown to promote glioblastoma migration, invasion, and EMT via GSK-3\\u03b2/\\u03b2-catenin signaling.\",\n      \"evidence\": \"siRNA/overexpression in GBM cell lines, EMT-marker Western blots, pharmacological GSK-3\\u03b2 inhibition, nuclear fractionation, and immunohistochemistry\",\n      \"pmids\": [\"33178594\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Pathway placement relies on a pharmacological inhibitor\", \"Direct molecular link between BYSL and GSK-3\\u03b2 not demonstrated\", \"Single lab, single tumor type\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Defining a physical signaling partner: BYSL was found to complex with RIOK2 and mTOR and to positively regulate AKT/mTOR signaling in glioma.\",\n      \"evidence\": \"Reciprocal Co-IP, double immunofluorescence co-localization, AKT/mTOR Western blots, overexpression/knockdown, and orthotopic xenograft\",\n      \"pmids\": [\"33628587\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct binary interactions within the BYSL\\u2013RIOK2\\u2013mTOR complex not resolved\", \"Relationship between this signaling role and the canonical ribosome biogenesis role unclear\", \"Single lab\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Establishing post-transcriptional control: miR-378a-3p was shown to directly target the BYSL 3'-UTR, and BYSL was linked to Nrf2 induction under hypoxia.\",\n      \"evidence\": \"Dual-luciferase reporter and rescue assays with Western blot in osteosarcoma cells\",\n      \"pmids\": [\"35154253\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking BYSL to Nrf2 not defined\", \"Single lab, single cancer type\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Identifying transcriptional control and a proliferative requirement: c-MYC was shown to directly bind the BYSL promoter, and BYSL suppression caused G0/G1 arrest and reduced PI3K/AKT phosphorylation in AML.\",\n      \"evidence\": \"shRNA knockdown, ChIP-qPCR, cell cycle and colony-formation assays, and PI3K/AKT Western blots in AML cell lines\",\n      \"pmids\": [\"41854887\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether PI3K/AKT changes are direct or secondary to reduced ribosome biogenesis not resolved\", \"Single study\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the conserved nucleolar 40S-biogenesis function mechanistically connects to the AKT/mTOR, GSK-3\\u03b2/\\u03b2-catenin, and c-MYC signaling roles reported in cancer remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of BYSL within the pre-rRNA processing machinery in the corpus\", \"Direct binding partners of mammalian BYSL during ribosome biogenesis not enumerated\", \"Causal ordering between ribosome biogenesis defects and signaling outputs not established\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [2, 4]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [1, 4]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [6, 7]}\n    ],\n    \"complexes\": [\"mTORC2\"],\n    \"partners\": [\"NOP1\", \"RIOK2\", \"MTOR\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}