{"gene":"RBPJL","run_date":"2026-06-10T06:43:36","timeline":{"discoveries":[{"year":1997,"finding":"RBP-L binds to a DNA sequence almost identical to that recognized by RBP-J (the mammalian Suppressor of Hairless), demonstrating sequence-specific DNA binding activity. Unlike RBP-J, RBP-L does not interact with any of the four known mouse Notch proteins in vivo or in vitro.","method":"DNA binding assays; multiple in vivo and in vitro protein-protein interaction assays","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — direct DNA binding assay and multiple interaction assays in a single focused study; negative Notch interaction result supported by several orthogonal methods","pmids":["9111338"],"is_preprint":false},{"year":1997,"finding":"RBP-L cooperates with EBNA-2 in transcriptional activation, but does not show significant direct protein-protein interaction with EBNA-2 detectable by several assays — in contrast to RBP-J, which physically associates with EBNA-2.","method":"Transcriptional activation assays; multiple in vivo and in vitro protein-protein interaction assays","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional cooperation demonstrated by transcription assay, negative physical interaction confirmed by multiple methods, single lab","pmids":["9111338"],"is_preprint":false},{"year":1999,"finding":"RBP-L protein is expressed in a cell-type-specific manner: in the brain it is detected in layer VI of the cerebral cortex, pyramidal cell layer of the hippocampus, and granule cell layer of the dentate gyrus. The upstream promoter driving neuronal expression is regulated by neuronal activity, while a distinct downstream promoter drives expression in lung.","method":"Targeted gene disruption with in-frame nlacZ reporter insertion; β-galactosidase histochemistry in knock-in mice","journal":"Journal of biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct knock-in reporter experiment in mice; localization linked to promoter activity but no functional consequence directly tested","pmids":["10502683"],"is_preprint":false},{"year":2006,"finding":"RBP-L (and RBP-J) serves as the third subunit of the trimeric PTF1 transcription factor complex, associating with P48/PTF1a via two conserved tryptophan-containing motifs on P48 that mimic the Notch intracellular domain (NotchIC) docking motif. RBP-L occupies this same docking site, rendering the PTF1 complex Notch-independent. Unlike RBP-J, RBP-L does not bind NotchIC. PTF1 in mature acinar cells exclusively contains the RBP-L isoform and is bound to promoters of acinar-specific genes.","method":"Co-immunoprecipitation; mutagenesis of tryptophan-containing motifs; chromatin immunoprecipitation (ChIP); in vitro binding assays","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — reciprocal co-IP, mutagenesis, ChIP, and in vitro binding in a single focused study with multiple orthogonal methods","pmids":["16354684"],"is_preprint":false},{"year":2006,"finding":"Mutations in P48/PTF1a that delete one or both RBP-interacting tryptophan motifs abolish RBP-L (or RBP-J) binding and are associated with a human genetic disorder (pancreatic and cerebellar agenesis), establishing that the P48–RBP-L/J interaction is required for proper embryonic development.","method":"Mutagenesis of RBP-interacting motifs; genetic analysis of human disease variants","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — mutagenesis with defined binding loss plus human genetic validation in same study","pmids":["16354684"],"is_preprint":false},{"year":2010,"finding":"Replacement of Rbpj by Rbpjl in the PTF1 complex (forming PTF1-L) drives the final maturation of pancreatic acinar cells by maximizing expression of secretory enzyme genes (up to 99% reduction in their mRNAs in Rbpjl knockout mice), stimulating mitochondrial metabolism, and completing the secretory apparatus. Loss of Rbpjl causes PTF1-J to persist and partially substitute, with gene expression levels correlated with extent of replacement.","method":"Rbpjl knockout mice; genome-wide mRNA profiling; ChIP to identify PTF1-L target genes","journal":"Gastroenterology","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean KO mouse with defined cellular phenotype, genome-wide expression profiling, and ChIP for direct targets; replicated across multiple gene classes","pmids":["20398665"],"is_preprint":false},{"year":2018,"finding":"The p.Thr280Met variant of RBPJL reduces protein stability (lower RBPJL protein levels despite comparable RNA) and impairs transactivation of RBPJL-responsive promoters including CTRB1, as shown by luciferase reporter assays. Knockdown of Rbpjl in mouse pancreatic acinar cells decreases mRNA expression of exocrine enzyme genes (e.g., Ctrb).","method":"Luciferase reporter assay; protein expression analysis of allelic variants; Rbpjl knockdown in mouse pancreatic acinar cells with mRNA quantification","journal":"European journal of human genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple in vitro functional assays and knockdown experiment in primary cells, single lab","pmids":["29302047"],"is_preprint":false},{"year":2022,"finding":"Rbpjl binds directly to the promoter region of Arid5a (as shown by ChIP, EMSA, and dual-luciferase reporter assays) and represses Arid5a expression, thereby suppressing IL-6/STAT3 signaling and reducing pancreatic acinar cell inflammation. Re-expression of Rbpjl in LPS-treated acinar cells or cerulein-induced acute pancreatitis mice alleviates cell damage and inflammation through this axis.","method":"ChIP; EMSA; dual-luciferase reporter assay; Rbpjl overexpression and knockdown in pancreatic acinar cells; in vivo mouse model of acute pancreatitis","journal":"Cell & bioscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — three orthogonal methods for promoter binding, functional validation in vitro and in vivo; single lab","pmids":["35725649"],"is_preprint":false},{"year":2025,"finding":"Fam102a interacts with Rbpjl and promotes its nuclear translocation; the Fam102a-Rbpjl axis enhances expression of Osterix (Sp7), a transcription factor essential for osteoblast differentiation. Functional mutation in Rbpjl or deletion of Fam102a leads to osteopenia with reduced osteoblastic bone formation.","method":"Co-immunoprecipitation; nuclear translocation assays; knockout mouse models (Fam102a deletion, Rbpjl functional mutation); bone formation phenotyping","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP, nuclear translocation assay, and two KO/mutant mouse models in a single study; single lab","pmids":["39747056"],"is_preprint":false}],"current_model":"RBPJL (RBP-L) is a sequence-specific DNA-binding transcription factor that functions as the tissue-restricted third subunit of the trimeric PTF1 complex in mature pancreatic acinar cells: it is recruited by P48/PTF1a via conserved tryptophan motifs, cannot bind Notch intracellular domain (rendering PTF1-L Notch-independent), drives terminal acinar differentiation by directly activating digestive enzyme genes, directly represses Arid5a to suppress IL-6/STAT3 inflammatory signaling, and in osteoblasts is translocated to the nucleus by Fam102a to activate Osterix expression during bone formation."},"narrative":{"mechanistic_narrative":"RBPJL (RBP-L) is a sequence-specific DNA-binding transcription factor that serves as the tissue-restricted subunit of the trimeric PTF1 complex, driving terminal differentiation programs in pancreatic acinar cells and contributing to osteoblast development [PMID:9111338, PMID:16354684, PMID:20398665]. It recognizes a DNA sequence almost identical to that bound by RBP-J but, unlike RBP-J, does not interact with Notch proteins [PMID:9111338]. Within PTF1, RBPJL is recruited by P48/PTF1a through two conserved tryptophan-containing motifs that mimic the Notch intracellular domain docking motif; because RBPJL occupies this site yet cannot bind NotchIC, the resulting PTF1-L complex is rendered Notch-independent [PMID:16354684]. Replacement of RBP-J by RBPJL in PTF1 drives final maturation of acinar cells by maximizing secretory digestive enzyme gene expression (e.g., CTRB1/Ctrb), stimulating mitochondrial metabolism, and completing the secretory apparatus [PMID:20398665, PMID:29302047]. RBPJL also directly binds and represses the Arid5a promoter, thereby suppressing IL-6/STAT3 inflammatory signaling and limiting acinar cell damage in pancreatitis models [PMID:35725649]. Beyond the pancreas, RBPJL is translocated to the nucleus by Fam102a to activate Osterix (Sp7), supporting osteoblastic bone formation [PMID:39747056]. The P48–RBP interaction is required for proper development, with disrupting mutations associated with human pancreatic and cerebellar agenesis [PMID:16354684].","teleology":[{"year":1997,"claim":"Established that RBP-L is a sequence-specific DNA-binding factor closely related to RBP-J in target recognition but mechanistically distinct in being unable to engage Notch, defining it as a Notch-independent counterpart.","evidence":"DNA binding assays and multiple in vivo/in vitro protein-protein interaction assays against mouse Notch proteins","pmids":["9111338"],"confidence":"High","gaps":["Did not identify physiological target genes or in vivo binding sites","Cellular and tissue context of activity not yet defined"]},{"year":1997,"claim":"Showed RBP-L can functionally cooperate with EBNA-2 in transcriptional activation without detectable direct physical interaction, distinguishing its coactivator behavior from RBP-J.","evidence":"Transcriptional activation assays plus multiple interaction assays","pmids":["9111338"],"confidence":"Medium","gaps":["Mechanism of cooperation without binding unresolved","Relevance to endogenous RBP-L function unclear"]},{"year":1999,"claim":"Mapped cell-type-specific RBP-L expression and revealed dual promoter usage, indicating tissue-restricted and activity-regulated transcriptional control of the gene.","evidence":"Knock-in nlacZ reporter and beta-galactosidase histochemistry in mice","pmids":["10502683"],"confidence":"Medium","gaps":["No functional consequence of expression pattern tested","Neuronal role of RBP-L not characterized"]},{"year":2006,"claim":"Defined RBPJL as the third subunit of the PTF1 complex recruited by P48/PTF1a via tryptophan motifs that mimic NotchIC docking, explaining how PTF1-L is rendered Notch-independent and targets acinar-specific promoters.","evidence":"Reciprocal co-IP, tryptophan-motif mutagenesis, ChIP, and in vitro binding","pmids":["16354684"],"confidence":"High","gaps":["Full set of acinar target genes not enumerated here","Structural basis of motif mimicry not resolved"]},{"year":2006,"claim":"Linked loss of the P48–RBP interaction to a human developmental disorder, establishing that this assembly is required for normal embryonic development.","evidence":"Mutagenesis of RBP-interacting motifs plus human disease variant analysis (pancreatic and cerebellar agenesis)","pmids":["16354684"],"confidence":"High","gaps":["Did not separate RBPJL-specific from RBP-J-specific contributions to the disorder"]},{"year":2010,"claim":"Demonstrated that swapping RBP-J for RBPJL in PTF1 drives the final maturation of acinar cells, directly tying RBPJL to secretory enzyme gene output, mitochondrial metabolism, and the secretory apparatus.","evidence":"Rbpjl knockout mice with genome-wide mRNA profiling and ChIP for direct targets","pmids":["20398665"],"confidence":"High","gaps":["Mechanism of partial PTF1-J substitution not fully defined","Direct vs indirect regulation of metabolic genes not separated"]},{"year":2018,"claim":"Connected a destabilizing RBPJL variant (p.Thr280Met) to reduced transactivation of acinar promoters, providing human-relevant functional evidence for RBPJL's role in exocrine enzyme gene expression.","evidence":"Luciferase reporter assays, allelic protein stability analysis, and Rbpjl knockdown in mouse acinar cells","pmids":["29302047"],"confidence":"Medium","gaps":["Disease penetrance and in vivo consequence of the variant not established","Single-lab functional assays"]},{"year":2022,"claim":"Identified Arid5a as a direct RBPJL repression target, revealing a mechanism by which RBPJL restrains IL-6/STAT3 inflammatory signaling and protects acinar cells.","evidence":"ChIP, EMSA, dual-luciferase reporter, overexpression/knockdown, and cerulein pancreatitis mouse model","pmids":["35725649"],"confidence":"Medium","gaps":["Single lab","Whether repression occurs within the PTF1 complex context not defined"]},{"year":2025,"claim":"Extended RBPJL function beyond the pancreas by showing Fam102a-mediated nuclear translocation activates Osterix to promote osteoblast bone formation.","evidence":"Co-IP, nuclear translocation assays, and Fam102a-deletion / Rbpjl-mutant knockout mouse models with bone phenotyping","pmids":["39747056"],"confidence":"Medium","gaps":["Whether PTF1-like assembly operates in osteoblasts unknown","Single lab; direct binding to Osterix promoter not established here"]},{"year":null,"claim":"How RBPJL switches between transcriptional activation (digestive enzymes, Osterix) and direct repression (Arid5a), and what determines its tissue-specific partner usage, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of RBPJL bound to distinct cofactors","Mechanism toggling activation vs repression unknown","Neuronal RBP-L function uncharacterized in the corpus"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[0,3,7]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[0,3,5,7]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[3,8]}],"pathway":[{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[3,5,7]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[4,5,8]}],"complexes":["PTF1 complex (PTF1-L)"],"partners":["PTF1A","FAM102A"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9UBG7","full_name":"Recombining binding protein suppressor of hairless-like protein","aliases":["Transcription factor RBP-L"],"length_aa":517,"mass_kda":56.8,"function":"Putative transcription factor, which cooperates with EBNA2 to activate transcription","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/Q9UBG7/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/RBPJL","classification":"Not Classified","n_dependent_lines":7,"n_total_lines":1208,"dependency_fraction":0.005794701986754967},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/RBPJL","total_profiled":1310},"omim":[{"mim_id":"616104","title":"RBPJ-LIKE PROTEIN; RBPJL","url":"https://www.omim.org/entry/616104"},{"mim_id":"607194","title":"PANCREAS TRANSCRIPTION FACTOR 1, ALPHA SUBUNIT; PTF1A","url":"https://www.omim.org/entry/607194"},{"mim_id":"260350","title":"PANCREATIC CANCER","url":"https://www.omim.org/entry/260350"},{"mim_id":"147183","title":"RECOMBINATION SIGNAL-BINDING PROTEIN FOR IMMUNOGLOBULIN KAPPA J REGION; RBPJ","url":"https://www.omim.org/entry/147183"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"pancreas","ntpm":919.9}],"url":"https://www.proteinatlas.org/search/RBPJL"},"hgnc":{"alias_symbol":["RBP-L","SUH","SUHL"],"prev_symbol":["RBPSUHL"]},"alphafold":{"accession":"Q9UBG7","domains":[{"cath_id":"2.60.40.1450","chopping":"67-102_119-193","consensus_level":"high","plddt":89.8285,"start":67,"end":193},{"cath_id":"2.80.10.50","chopping":"214-365","consensus_level":"high","plddt":88.8312,"start":214,"end":365},{"cath_id":"2.60.40.10","chopping":"380-478_507-516","consensus_level":"high","plddt":85.8494,"start":380,"end":516}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UBG7","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UBG7-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UBG7-F1-predicted_aligned_error_v6.png","plddt_mean":80.19},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RBPJL","jax_strain_url":"https://www.jax.org/strain/search?query=RBPJL"},"sequence":{"accession":"Q9UBG7","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9UBG7.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9UBG7/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UBG7"}},"corpus_meta":[{"pmid":"16354684","id":"PMC_16354684","title":"PTF1 is an organ-specific and Notch-independent basic helix-loop-helix complex containing the mammalian Suppressor of Hairless (RBP-J) or its paralogue, RBP-L.","date":"2006","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/16354684","citation_count":169,"is_preprint":false},{"pmid":"9111338","id":"PMC_9111338","title":"RBP-L, a transcription factor related to RBP-Jkappa.","date":"1997","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/9111338","citation_count":115,"is_preprint":false},{"pmid":"20398665","id":"PMC_20398665","title":"Replacement of Rbpj with Rbpjl in the PTF1 complex controls the final maturation of pancreatic acinar cells.","date":"2010","source":"Gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/20398665","citation_count":79,"is_preprint":false},{"pmid":"30659066","id":"PMC_30659066","title":"Targeted Endoplasmic Reticulum Localization of Storage Protein mRNAs Requires the RNA-Binding Protein RBP-L.","date":"2019","source":"Plant physiology","url":"https://pubmed.ncbi.nlm.nih.gov/30659066","citation_count":23,"is_preprint":false},{"pmid":"11549321","id":"PMC_11549321","title":"Characterization of the mouse matrilin-4 gene: a 5' antiparallel overlap with the gene encoding the transcription factor RBP-l.","date":"2001","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/11549321","citation_count":13,"is_preprint":false},{"pmid":"39747056","id":"PMC_39747056","title":"Fam102a translocates Runx2 and Rbpjl to facilitate Osterix expression and bone formation.","date":"2025","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/39747056","citation_count":10,"is_preprint":false},{"pmid":"35725649","id":"PMC_35725649","title":"Blockade of the Arid5a/IL-6/STAT3 axis underlies the anti-inflammatory effect of Rbpjl in acute pancreatitis.","date":"2022","source":"Cell & bioscience","url":"https://pubmed.ncbi.nlm.nih.gov/35725649","citation_count":10,"is_preprint":false},{"pmid":"29302047","id":"PMC_29302047","title":"Functional and association analysis of an Amerindian-derived population-specific p.(Thr280Met) variant in RBPJL, a component of the PTF1 complex.","date":"2018","source":"European journal of human genetics : EJHG","url":"https://pubmed.ncbi.nlm.nih.gov/29302047","citation_count":8,"is_preprint":false},{"pmid":"10502683","id":"PMC_10502683","title":"Studies on the cell-type specific expression of RBP-L, a RBP-J family member, by replacement insertion of beta-galactosidase.","date":"1999","source":"Journal of biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10502683","citation_count":8,"is_preprint":false},{"pmid":"32994998","id":"PMC_32994998","title":"p.P476S mutation of RBPJL inhibits the efficacy of anti-PD-1 therapy in oesophageal squamous cell carcinoma by blunting T-cell responses.","date":"2020","source":"Clinical & translational immunology","url":"https://pubmed.ncbi.nlm.nih.gov/32994998","citation_count":1,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.06.24.24309088","title":"Deciphering Distinct Genetic Risk Factors for FTLD-TDP Pathological Subtypes via Whole-Genome Sequencing","date":"2024-06-25","source":"bioRxiv","url":"https://doi.org/10.1101/2024.06.24.24309088","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7878,"output_tokens":2352,"usd":0.029457,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9482,"output_tokens":2974,"usd":0.06088,"stage2_stop_reason":"end_turn"},"total_usd":0.090337,"stage1_batch_id":"msgbatch_01CNoDbkChHEkgrJnL7BwtGJ","stage2_batch_id":"msgbatch_016Y4x9E9Wg5VQDANj9quSQD","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1997,\n      \"finding\": \"RBP-L binds to a DNA sequence almost identical to that recognized by RBP-J (the mammalian Suppressor of Hairless), demonstrating sequence-specific DNA binding activity. Unlike RBP-J, RBP-L does not interact with any of the four known mouse Notch proteins in vivo or in vitro.\",\n      \"method\": \"DNA binding assays; multiple in vivo and in vitro protein-protein interaction assays\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — direct DNA binding assay and multiple interaction assays in a single focused study; negative Notch interaction result supported by several orthogonal methods\",\n      \"pmids\": [\"9111338\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"RBP-L cooperates with EBNA-2 in transcriptional activation, but does not show significant direct protein-protein interaction with EBNA-2 detectable by several assays — in contrast to RBP-J, which physically associates with EBNA-2.\",\n      \"method\": \"Transcriptional activation assays; multiple in vivo and in vitro protein-protein interaction assays\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional cooperation demonstrated by transcription assay, negative physical interaction confirmed by multiple methods, single lab\",\n      \"pmids\": [\"9111338\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"RBP-L protein is expressed in a cell-type-specific manner: in the brain it is detected in layer VI of the cerebral cortex, pyramidal cell layer of the hippocampus, and granule cell layer of the dentate gyrus. The upstream promoter driving neuronal expression is regulated by neuronal activity, while a distinct downstream promoter drives expression in lung.\",\n      \"method\": \"Targeted gene disruption with in-frame nlacZ reporter insertion; β-galactosidase histochemistry in knock-in mice\",\n      \"journal\": \"Journal of biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct knock-in reporter experiment in mice; localization linked to promoter activity but no functional consequence directly tested\",\n      \"pmids\": [\"10502683\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"RBP-L (and RBP-J) serves as the third subunit of the trimeric PTF1 transcription factor complex, associating with P48/PTF1a via two conserved tryptophan-containing motifs on P48 that mimic the Notch intracellular domain (NotchIC) docking motif. RBP-L occupies this same docking site, rendering the PTF1 complex Notch-independent. Unlike RBP-J, RBP-L does not bind NotchIC. PTF1 in mature acinar cells exclusively contains the RBP-L isoform and is bound to promoters of acinar-specific genes.\",\n      \"method\": \"Co-immunoprecipitation; mutagenesis of tryptophan-containing motifs; chromatin immunoprecipitation (ChIP); in vitro binding assays\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — reciprocal co-IP, mutagenesis, ChIP, and in vitro binding in a single focused study with multiple orthogonal methods\",\n      \"pmids\": [\"16354684\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Mutations in P48/PTF1a that delete one or both RBP-interacting tryptophan motifs abolish RBP-L (or RBP-J) binding and are associated with a human genetic disorder (pancreatic and cerebellar agenesis), establishing that the P48–RBP-L/J interaction is required for proper embryonic development.\",\n      \"method\": \"Mutagenesis of RBP-interacting motifs; genetic analysis of human disease variants\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — mutagenesis with defined binding loss plus human genetic validation in same study\",\n      \"pmids\": [\"16354684\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Replacement of Rbpj by Rbpjl in the PTF1 complex (forming PTF1-L) drives the final maturation of pancreatic acinar cells by maximizing expression of secretory enzyme genes (up to 99% reduction in their mRNAs in Rbpjl knockout mice), stimulating mitochondrial metabolism, and completing the secretory apparatus. Loss of Rbpjl causes PTF1-J to persist and partially substitute, with gene expression levels correlated with extent of replacement.\",\n      \"method\": \"Rbpjl knockout mice; genome-wide mRNA profiling; ChIP to identify PTF1-L target genes\",\n      \"journal\": \"Gastroenterology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean KO mouse with defined cellular phenotype, genome-wide expression profiling, and ChIP for direct targets; replicated across multiple gene classes\",\n      \"pmids\": [\"20398665\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"The p.Thr280Met variant of RBPJL reduces protein stability (lower RBPJL protein levels despite comparable RNA) and impairs transactivation of RBPJL-responsive promoters including CTRB1, as shown by luciferase reporter assays. Knockdown of Rbpjl in mouse pancreatic acinar cells decreases mRNA expression of exocrine enzyme genes (e.g., Ctrb).\",\n      \"method\": \"Luciferase reporter assay; protein expression analysis of allelic variants; Rbpjl knockdown in mouse pancreatic acinar cells with mRNA quantification\",\n      \"journal\": \"European journal of human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple in vitro functional assays and knockdown experiment in primary cells, single lab\",\n      \"pmids\": [\"29302047\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Rbpjl binds directly to the promoter region of Arid5a (as shown by ChIP, EMSA, and dual-luciferase reporter assays) and represses Arid5a expression, thereby suppressing IL-6/STAT3 signaling and reducing pancreatic acinar cell inflammation. Re-expression of Rbpjl in LPS-treated acinar cells or cerulein-induced acute pancreatitis mice alleviates cell damage and inflammation through this axis.\",\n      \"method\": \"ChIP; EMSA; dual-luciferase reporter assay; Rbpjl overexpression and knockdown in pancreatic acinar cells; in vivo mouse model of acute pancreatitis\",\n      \"journal\": \"Cell & bioscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — three orthogonal methods for promoter binding, functional validation in vitro and in vivo; single lab\",\n      \"pmids\": [\"35725649\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Fam102a interacts with Rbpjl and promotes its nuclear translocation; the Fam102a-Rbpjl axis enhances expression of Osterix (Sp7), a transcription factor essential for osteoblast differentiation. Functional mutation in Rbpjl or deletion of Fam102a leads to osteopenia with reduced osteoblastic bone formation.\",\n      \"method\": \"Co-immunoprecipitation; nuclear translocation assays; knockout mouse models (Fam102a deletion, Rbpjl functional mutation); bone formation phenotyping\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP, nuclear translocation assay, and two KO/mutant mouse models in a single study; single lab\",\n      \"pmids\": [\"39747056\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RBPJL (RBP-L) is a sequence-specific DNA-binding transcription factor that functions as the tissue-restricted third subunit of the trimeric PTF1 complex in mature pancreatic acinar cells: it is recruited by P48/PTF1a via conserved tryptophan motifs, cannot bind Notch intracellular domain (rendering PTF1-L Notch-independent), drives terminal acinar differentiation by directly activating digestive enzyme genes, directly represses Arid5a to suppress IL-6/STAT3 inflammatory signaling, and in osteoblasts is translocated to the nucleus by Fam102a to activate Osterix expression during bone formation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RBPJL (RBP-L) is a sequence-specific DNA-binding transcription factor that serves as the tissue-restricted subunit of the trimeric PTF1 complex, driving terminal differentiation programs in pancreatic acinar cells and contributing to osteoblast development [#0, #3, #5]. It recognizes a DNA sequence almost identical to that bound by RBP-J but, unlike RBP-J, does not interact with Notch proteins [#0]. Within PTF1, RBPJL is recruited by P48/PTF1a through two conserved tryptophan-containing motifs that mimic the Notch intracellular domain docking motif; because RBPJL occupies this site yet cannot bind NotchIC, the resulting PTF1-L complex is rendered Notch-independent [#3]. Replacement of RBP-J by RBPJL in PTF1 drives final maturation of acinar cells by maximizing secretory digestive enzyme gene expression (e.g., CTRB1/Ctrb), stimulating mitochondrial metabolism, and completing the secretory apparatus [#5, #6]. RBPJL also directly binds and represses the Arid5a promoter, thereby suppressing IL-6/STAT3 inflammatory signaling and limiting acinar cell damage in pancreatitis models [#7]. Beyond the pancreas, RBPJL is translocated to the nucleus by Fam102a to activate Osterix (Sp7), supporting osteoblastic bone formation [#8]. The P48–RBP interaction is required for proper development, with disrupting mutations associated with human pancreatic and cerebellar agenesis [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 1997,\n      \"claim\": \"Established that RBP-L is a sequence-specific DNA-binding factor closely related to RBP-J in target recognition but mechanistically distinct in being unable to engage Notch, defining it as a Notch-independent counterpart.\",\n      \"evidence\": \"DNA binding assays and multiple in vivo/in vitro protein-protein interaction assays against mouse Notch proteins\",\n      \"pmids\": [\"9111338\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify physiological target genes or in vivo binding sites\", \"Cellular and tissue context of activity not yet defined\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Showed RBP-L can functionally cooperate with EBNA-2 in transcriptional activation without detectable direct physical interaction, distinguishing its coactivator behavior from RBP-J.\",\n      \"evidence\": \"Transcriptional activation assays plus multiple interaction assays\",\n      \"pmids\": [\"9111338\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of cooperation without binding unresolved\", \"Relevance to endogenous RBP-L function unclear\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Mapped cell-type-specific RBP-L expression and revealed dual promoter usage, indicating tissue-restricted and activity-regulated transcriptional control of the gene.\",\n      \"evidence\": \"Knock-in nlacZ reporter and beta-galactosidase histochemistry in mice\",\n      \"pmids\": [\"10502683\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional consequence of expression pattern tested\", \"Neuronal role of RBP-L not characterized\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Defined RBPJL as the third subunit of the PTF1 complex recruited by P48/PTF1a via tryptophan motifs that mimic NotchIC docking, explaining how PTF1-L is rendered Notch-independent and targets acinar-specific promoters.\",\n      \"evidence\": \"Reciprocal co-IP, tryptophan-motif mutagenesis, ChIP, and in vitro binding\",\n      \"pmids\": [\"16354684\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full set of acinar target genes not enumerated here\", \"Structural basis of motif mimicry not resolved\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Linked loss of the P48–RBP interaction to a human developmental disorder, establishing that this assembly is required for normal embryonic development.\",\n      \"evidence\": \"Mutagenesis of RBP-interacting motifs plus human disease variant analysis (pancreatic and cerebellar agenesis)\",\n      \"pmids\": [\"16354684\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not separate RBPJL-specific from RBP-J-specific contributions to the disorder\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Demonstrated that swapping RBP-J for RBPJL in PTF1 drives the final maturation of acinar cells, directly tying RBPJL to secretory enzyme gene output, mitochondrial metabolism, and the secretory apparatus.\",\n      \"evidence\": \"Rbpjl knockout mice with genome-wide mRNA profiling and ChIP for direct targets\",\n      \"pmids\": [\"20398665\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of partial PTF1-J substitution not fully defined\", \"Direct vs indirect regulation of metabolic genes not separated\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Connected a destabilizing RBPJL variant (p.Thr280Met) to reduced transactivation of acinar promoters, providing human-relevant functional evidence for RBPJL's role in exocrine enzyme gene expression.\",\n      \"evidence\": \"Luciferase reporter assays, allelic protein stability analysis, and Rbpjl knockdown in mouse acinar cells\",\n      \"pmids\": [\"29302047\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Disease penetrance and in vivo consequence of the variant not established\", \"Single-lab functional assays\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identified Arid5a as a direct RBPJL repression target, revealing a mechanism by which RBPJL restrains IL-6/STAT3 inflammatory signaling and protects acinar cells.\",\n      \"evidence\": \"ChIP, EMSA, dual-luciferase reporter, overexpression/knockdown, and cerulein pancreatitis mouse model\",\n      \"pmids\": [\"35725649\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Whether repression occurs within the PTF1 complex context not defined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Extended RBPJL function beyond the pancreas by showing Fam102a-mediated nuclear translocation activates Osterix to promote osteoblast bone formation.\",\n      \"evidence\": \"Co-IP, nuclear translocation assays, and Fam102a-deletion / Rbpjl-mutant knockout mouse models with bone phenotyping\",\n      \"pmids\": [\"39747056\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether PTF1-like assembly operates in osteoblasts unknown\", \"Single lab; direct binding to Osterix promoter not established here\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How RBPJL switches between transcriptional activation (digestive enzymes, Osterix) and direct repression (Arid5a), and what determines its tissue-specific partner usage, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of RBPJL bound to distinct cofactors\", \"Mechanism toggling activation vs repression unknown\", \"Neuronal RBP-L function uncharacterized in the corpus\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [0, 3, 7]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [0, 3, 5, 7]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [3, 8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [3, 5, 7]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [4, 5, 8]}\n    ],\n    \"complexes\": [\"PTF1 complex (PTF1-L)\"],\n    \"partners\": [\"PTF1A\", \"FAM102A\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":7,"faith_pct":85.71428571428571}}