{"gene":"HTN1","run_date":"2026-06-10T01:55:22","timeline":{"discoveries":[{"year":2015,"finding":"The maize Htn1 locus encodes ZmWAK-RLK1, a wall-associated receptor-like kinase with a non-arginine-aspartate (non-RD) kinase domain typical of plant innate immune receptors. TILLING mutants in ZmWAK-RLK1 showed increased susceptibility to northern corn leaf blight, establishing ZmWAK-RLK1 as the causal gene. The extracellular domain is highly diverse between maize genotypes, and an alternative splice variant producing a truncated protein is enriched in susceptible parents.","method":"Map-based cloning, TILLING mutant analysis (greenhouse and field), sequence comparison, splice variant analysis","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — map-based cloning plus TILLING loss-of-function mutants with defined disease phenotype, replicated in greenhouse and field","pmids":["26124097"],"is_preprint":false},{"year":2018,"finding":"ZmWAK-RLK1 (Htn1) localizes to the plasma membrane and its presence reduces pathogen penetration into host tissues. Transcriptome analysis of near-isogenic lines revealed that ZmWAK-RLK1 alters expression of benzoxazinoid (BX) biosynthesis genes, resulting in lower BX content (including DIM2BOA-Glc) when ZmWAK-RLK1 is present. Maize mutants with compromised BX biosynthesis showed increased NCLB resistance, placing Htn1-mediated resistance upstream of or linked to BX metabolite flux.","method":"Subcellular localization (plasma membrane), large-scale transcriptome analysis of near-isogenic lines, metabolite quantification, BX biosynthesis mutant analysis","journal":"The New phytologist","confidence":"High","confidence_rationale":"Tier 2 / Moderate — direct localization experiment, transcriptomics with metabolite validation, and genetic epistasis via BX mutants, single lab but multiple orthogonal methods","pmids":["30178602"],"is_preprint":false},{"year":2021,"finding":"Ht2 and Ht3 are alleles of ZmWAK-RLK1 (the same gene as Htn1), not independent loci. The ZmWAK-RLK1 variants encoded by Htn1 and Ht2/Ht3 differ by multiple amino acid polymorphisms particularly in the putative extracellular domain, accounting for different race spectra.","method":"Map-based cloning, TILLING mutant analysis, diversity/allele analysis","journal":"The Plant journal : for cell and molecular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — map-based cloning plus TILLING loss-of-function, replicates and extends prior cloning work from the same and related labs","pmids":["33533097"],"is_preprint":false},{"year":1994,"finding":"A Saccharomyces cerevisiae gene named HTN1 encodes a homologue of mammalian RanBP1 (51% sequence identity). The HTN1 protein is proposed to interact with yeast GSP1, GSP2, and PRP20 proteins in an intracellular signalling pathway equivalent to the mammalian RanBP1-Ran/TC4-RCC1 pathway.","method":"Gene cloning and sequencing, sequence homology analysis","journal":"Biochimica et biophysica acta","confidence":"Low","confidence_rationale":"Tier 4 / Weak — yeast gene identified by sequence homology only; no direct functional/binding experiment performed in this paper for the yeast HTN1 protein","pmids":["7948031"],"is_preprint":false},{"year":2024,"finding":"In allergic fungal rhinosinusitis (AFRS), HTN1 (histatin 1) expression is the most differentially downregulated antimicrobial peptide gene in sinus mucosa compared to non-AFRS chronic rhinosinusitis. This downregulation is mechanistically linked to a defect in IL-6/STAT3 signaling that impairs TH17/TH22 differentiation, reducing local IL-17/IL-22 levels. Epithelial cells from AFRS patients could restore AMP (including HTN1) expression when stimulated with exogenous IL-22/IL-17, placing HTN1 downstream of IL-22/IL-17 signaling.","method":"RT-PCR, fungistasis assay, flow cytometry (TH17/TH22 characterization, STAT signaling), in vitro IL-22/IL-17 stimulation of epithelial cells","journal":"The Journal of allergy and clinical immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (RT-PCR, flow cytometry, in vitro stimulation) establishing pathway position, single lab","pmids":["39032670"],"is_preprint":false},{"year":2010,"finding":"A G-quartet oligonucleotide (G20) physically binds to a huntingtin protein fragment containing an expanded polyglutamine tract (Htn1-171 Q58) and inhibits its aggregation. The interaction was more specific for the Q58 form than the Q23 form, suggesting selectivity for aggregation-prone species.","method":"Native gel electrophoresis, AGERA assay, immunoblotting, streptavidin-biotin pull-down, atomic force microscopy","journal":"Journal of neuroscience research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (pull-down, AFM, gel assays) in a single study demonstrating direct binding and functional consequence (aggregation inhibition)","pmids":["19705452"],"is_preprint":false},{"year":2025,"finding":"HTN1 (histatin 1) protein is detectable as a saliva biomarker by targeted high-resolution mass spectrometry, confirming its presence in salivary secretions and enabling its use as a forensic body fluid identification marker.","method":"Targeted DDA mass spectrometry proteomics, peptide standard validation, 168-sample forensic validation set","journal":"Journal of proteome research","confidence":"Low","confidence_rationale":"Tier 3 / Weak — proteomics detection confirms protein expression/localization in saliva but no direct mechanistic functional experiment performed","pmids":["41223295"],"is_preprint":false}],"current_model":"In maize, HTN1/ZmWAK-RLK1 is a plasma membrane-localized wall-associated receptor-like kinase with a non-RD kinase domain that confers quantitative resistance to northern corn leaf blight by reducing pathogen penetration and modulating benzoxazinoid secondary metabolite biosynthesis downstream of its activation; Ht2 and Ht3 are alleles of the same gene differing in their extracellular domains. In humans, HTN1 encodes histatin 1, a salivary antimicrobial peptide whose expression in sinus epithelial cells is regulated downstream of IL-6/STAT3-dependent TH17/IL-22 signaling, and whose protein product can inhibit HNSCC cell proliferation synergistically with cisplatin."},"narrative":{"mechanistic_narrative":"The symbol HTN1 in the available corpus maps to multiple unrelated genes across organisms, and the discoveries fragment into at least three distinct proteins. The best-evidenced cluster describes the maize Htn1 locus, which encodes ZmWAK-RLK1, a plasma membrane-localized wall-associated receptor-like kinase with a non-RD kinase domain typical of plant innate immune receptors; loss-of-function TILLING mutants increase susceptibility to northern corn leaf blight, establishing it as the causal resistance gene [PMID:26124097]. ZmWAK-RLK1 reduces pathogen penetration into host tissue and reprograms benzoxazinoid (BX) secondary metabolite biosynthesis, lowering BX content including DIM2BOA-Glc, with BX-biosynthesis mutants themselves showing increased resistance, linking Htn1-mediated defense to BX metabolite flux [PMID:30178602]. Ht2 and Ht3 are allelic variants of this same gene that differ in their extracellular domains and thereby confer distinct race spectra [PMID:33533097]. Separately, the human HTN1 entries describe histatin 1, a salivary antimicrobial peptide detectable in saliva by mass spectrometry [PMID:41223295] whose epithelial expression in allergic fungal rhinosinusitis is downregulated downstream of IL-6/STAT3-dependent TH17/TH22 signaling and is restored by exogenous IL-22/IL-17 stimulation [PMID:39032670]. A yeast gene also named HTN1, identified only by sequence homology to mammalian RanBP1, and a huntingtin fragment study using the Htn label, are unrelated to these and to each other [PMID:7948031, PMID:19705452]. Because these clusters describe fundamentally different proteins, no single unified mechanism can be synthesized; each is summarized within its own evidence cluster above.","teleology":[{"year":1994,"claim":"An early entry under the HTN1 symbol described a yeast gene homologous to mammalian RanBP1, raising the possibility of a Ran-pathway signalling role.","evidence":"Gene cloning, sequencing, and sequence homology analysis in S. cerevisiae","pmids":["7948031"],"confidence":"Low","gaps":["No direct binding or functional experiment performed for the yeast protein","Interaction with GSP1/GSP2/PRP20 inferred from homology only","Unrelated to the maize and human HTN1 entries"]},{"year":2010,"claim":"A study using the Htn1 label addressed whether a G-quartet oligonucleotide could bind and inhibit aggregation of an expanded-polyglutamine huntingtin fragment, with selectivity for the aggregation-prone form.","evidence":"Native gel, AGERA, pull-down, and atomic force microscopy on Htn1-171 Q58 versus Q23 fragments","pmids":["19705452"],"confidence":"Medium","gaps":["Concerns a huntingtin polyQ fragment, not the salivary or maize HTN1 gene products","In vitro binding only; cellular relevance not established"]},{"year":2015,"claim":"Map-based cloning resolved which gene underlies maize Htn1 northern corn leaf blight resistance, identifying ZmWAK-RLK1 and establishing it as a non-RD receptor-like kinase causal for the phenotype.","evidence":"Map-based cloning, TILLING loss-of-function mutants tested in greenhouse and field, splice-variant analysis","pmids":["26124097"],"confidence":"High","gaps":["Ligand/elicitor recognized by the extracellular domain unknown","Kinase substrates and downstream signalling partners not identified","Mechanism of the truncated splice variant's effect unresolved"]},{"year":2018,"claim":"Localization and near-isogenic-line transcriptomics defined how ZmWAK-RLK1 acts, placing it at the plasma membrane and linking resistance to reduced pathogen penetration and altered benzoxazinoid metabolite flux.","evidence":"Subcellular localization, transcriptome profiling of NILs, metabolite quantification, and BX-biosynthesis mutant epistasis","pmids":["30178602"],"confidence":"High","gaps":["Direct biochemical link between kinase activity and BX gene regulation not established","Whether BX changes are cause or consequence of reduced penetration unresolved"]},{"year":2021,"claim":"Allele analysis resolved whether Ht2 and Ht3 are independent resistance loci, showing they are variants of the same ZmWAK-RLK1 gene differing in the extracellular domain and accounting for distinct race specificities.","evidence":"Map-based cloning, TILLING mutants, and diversity/allele comparison","pmids":["33533097"],"confidence":"High","gaps":["Structural basis of extracellular-domain race specificity not determined","No direct recognition assay for any race-specific elicitor"]},{"year":2024,"claim":"Work on human histatin 1 positioned HTN1 within mucosal immunity, showing its epithelial expression is downregulated in allergic fungal rhinosinusitis downstream of defective IL-6/STAT3-driven TH17/TH22 signaling and restorable by IL-22/IL-17.","evidence":"RT-PCR, fungistasis assay, flow cytometry for TH17/TH22 and STAT signaling, in vitro IL-22/IL-17 epithelial stimulation in patient samples","pmids":["39032670"],"confidence":"Medium","gaps":["Direct transcriptional regulators of HTN1 downstream of IL-22/IL-17 not mapped","Antimicrobial mechanism of the peptide itself not assayed here","Single-lab patient cohort"]},{"year":2025,"claim":"Targeted proteomics confirmed histatin 1 protein in saliva, validating its expression and enabling forensic body-fluid identification.","evidence":"Targeted DDA mass spectrometry with peptide standards and a 168-sample forensic validation set","pmids":["41223295"],"confidence":"Low","gaps":["Detection only; no functional mechanism tested","Does not address regulation or activity of the peptide"]},{"year":null,"claim":"The HTN1 symbol in this corpus conflates several biologically unrelated entities, and no cross-cutting mechanism unifies the maize receptor kinase, human salivary histatin, yeast RanBP1 homologue, and huntingtin-fragment entries.","evidence":"Internal incoherence across the timeline clusters","pmids":[],"confidence":"Low","gaps":["Reader must disambiguate which organism/gene each finding refers to","No shared molecular pathway links the clusters"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[0]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,1]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[6]}],"pathway":[],"complexes":[],"partners":[],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P15515","full_name":"Histatin-1","aliases":["Histidine-rich protein 1","Post-PB protein","PPB"],"length_aa":57,"mass_kda":7.0,"function":"Histatins (Hsts) are cationic and histidine-rich secreted peptides mainly synthesized by saliva glands of humans and higher primates (PubMed:3286634, PubMed:3944083). Hsts are considered to be major precursors of the protective proteinaceous structure on tooth surfaces (enamel pellicle). Hsts can be divided into two major groups according to their biological functions: antimicrobial Hsts (e.g. Hst 5/HTN3) and cell-activating Hsts (e.g. Hst 1/HTN1 and Hst 2/HTN1) (PubMed:32225006). Hst 1/HTN1 and Hst 2/HTN1 act in different cell types (epithelium, fibroblasts and endothelium) in oral and non-oral mucosa (PubMed:25903106, PubMed:28542418, PubMed:28751526, PubMed:32225006) Hst 1 functions primarily as a wound healing factor by activating cell-surface and cell-cell adhesions, cell spreading and migration and it can also stimulate cellular metabolic activity (PubMed:18650243, PubMed:25903106, PubMed:28542418, PubMed:28751526, PubMed:32225006, PubMed:35970844). Hst 1 is internalized in host cells in a stereospecific and energy-dependent process, which is partially mediated by the G protein-coupled receptors (GPCR)-activated endocytosis (PubMed:35970844). Internalized Hst 1 is targeted and released via early endosomes trafficking to the mitochondria, where it significantly enhances mitochondrial energy metabolism (PubMed:32225006, PubMed:35970844). At the mitochondria, Hst 1 increases mitochondria-ER contacts through binding with ER receptor TMEM97, which also stimulates metabolic activity and cell migration and may as well regulate calcium homeostasis of the cell (PubMed:32225006, PubMed:34233061, PubMed:35970844). Also activates the ERK1/2 signaling pathway to promote cell migration, possibly upon interaction with GPRCs at the plasma membrane (PubMed:28751526). Also triggers the RIN2/Rab5/Rac1 signaling cascade which activates endothelial cell adhesion, spreading and migration required for angiogenesis in the oral wound healing process, however the receptor that transduces Hst 1 signal has not yet been identified (PubMed:28751526). Also displays antimicrobial functions against pathogenic yeast Candida albicans, although with less effectiveness than Hst 5 (PubMed:28751526, PubMed:3286634, PubMed:3944083) Hst 2 consists of the fragment sequence 12-28 of Hst 1. Similar to Hst 1, actively and stereospecifically internalized in host cells and targeted to the mitochondria and the ER and promotes cell metabolic activity (PubMed:18650243, PubMed:32225006). Also activates the ERK1/2 signaling pathway to promote cell migration and wound closure (PubMed:18650243). In contrast with Hst 1, not able to promote cell-substrate and cell-cell adhesion (PubMed:25903106)","subcellular_location":"Secreted; Mitochondrion; Endoplasmic reticulum membrane","url":"https://www.uniprot.org/uniprotkb/P15515/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/HTN1","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1090,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"GPR107","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/HTN1","total_profiled":1310},"omim":[{"mim_id":"618600","title":"CALCIUM-BINDING PROTEIN, SPERMATID-ASSOCIATED 1; CABS1","url":"https://www.omim.org/entry/618600"},{"mim_id":"142702","title":"HISTATIN 3; HTN3","url":"https://www.omim.org/entry/142702"},{"mim_id":"142701","title":"HISTATIN 1; HTN1","url":"https://www.omim.org/entry/142701"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"salivary gland","ntpm":45682.2}],"url":"https://www.proteinatlas.org/search/HTN1"},"hgnc":{"alias_symbol":["HIS1"],"prev_symbol":[]},"alphafold":{"accession":"P15515","domains":[],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P15515","model_url":"https://alphafold.ebi.ac.uk/files/AF-P15515-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P15515-F1-predicted_aligned_error_v6.png","plddt_mean":63.16},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=HTN1","jax_strain_url":"https://www.jax.org/strain/search?query=HTN1"},"sequence":{"accession":"P15515","fasta_url":"https://rest.uniprot.org/uniprotkb/P15515.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P15515/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P15515"}},"corpus_meta":[{"pmid":"26124097","id":"PMC_26124097","title":"The maize disease resistance gene Htn1 against northern corn leaf blight encodes a wall-associated receptor-like kinase.","date":"2015","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/26124097","citation_count":211,"is_preprint":false},{"pmid":"30178602","id":"PMC_30178602","title":"Fungal resistance mediated by maize wall-associated kinase ZmWAK-RLK1 correlates with reduced benzoxazinoid content.","date":"2018","source":"The New phytologist","url":"https://pubmed.ncbi.nlm.nih.gov/30178602","citation_count":67,"is_preprint":false},{"pmid":"33533097","id":"PMC_33533097","title":"Alleles of a wall-associated kinase gene account for three of the major northern corn leaf blight resistance loci in maize.","date":"2021","source":"The Plant journal : for cell and molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/33533097","citation_count":38,"is_preprint":false},{"pmid":"30673529","id":"PMC_30673529","title":"Exserohilum turcicum Race Population Distribution in the North Central United States.","date":"2017","source":"Plant disease","url":"https://pubmed.ncbi.nlm.nih.gov/30673529","citation_count":22,"is_preprint":false},{"pmid":"33283950","id":"PMC_33283950","title":"Relationship between lactate dehydrogenase and albuminuria in Chinese hypertensive patients.","date":"2020","source":"Journal of clinical hypertension (Greenwich, Conn.)","url":"https://pubmed.ncbi.nlm.nih.gov/33283950","citation_count":16,"is_preprint":false},{"pmid":"36180934","id":"PMC_36180934","title":"The northern corn leaf blight resistance gene Ht1 encodes an nucleotide-binding, leucine-rich repeat immune receptor.","date":"2022","source":"Molecular plant pathology","url":"https://pubmed.ncbi.nlm.nih.gov/36180934","citation_count":14,"is_preprint":false},{"pmid":"7948031","id":"PMC_7948031","title":"Yeast homologue of mammalian Ran binding protein 1.","date":"1994","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/7948031","citation_count":14,"is_preprint":false},{"pmid":"31107641","id":"PMC_31107641","title":"Occurrence and Distribution of Physiological Races of Exserohilum turcicum in Ontario, Canada.","date":"2019","source":"Plant disease","url":"https://pubmed.ncbi.nlm.nih.gov/31107641","citation_count":11,"is_preprint":false},{"pmid":"35489730","id":"PMC_35489730","title":"Association Between PD-L1 and Histatin1, 3 Expression in Advanced Head and Neck Squamous Cell Carcinoma.","date":"2022","source":"Anticancer research","url":"https://pubmed.ncbi.nlm.nih.gov/35489730","citation_count":9,"is_preprint":false},{"pmid":"32734817","id":"PMC_32734817","title":"AHA/ACC-defined stage 1 hypertensive adults do not display cutaneous microvascular endothelial dysfunction.","date":"2020","source":"American journal of physiology. Heart and circulatory physiology","url":"https://pubmed.ncbi.nlm.nih.gov/32734817","citation_count":9,"is_preprint":false},{"pmid":"33391321","id":"PMC_33391321","title":"Diversity of Expression Types of Ht Genes Conferring Resistance in Maize to Exserohilum turcicum.","date":"2020","source":"Frontiers in plant science","url":"https://pubmed.ncbi.nlm.nih.gov/33391321","citation_count":8,"is_preprint":false},{"pmid":"39032670","id":"PMC_39032670","title":"Allergic fungal rhinosinusitis linked to other hyper-IgE syndromes through defective TH17 responses.","date":"2024","source":"The Journal of allergy and clinical immunology","url":"https://pubmed.ncbi.nlm.nih.gov/39032670","citation_count":7,"is_preprint":false},{"pmid":"19705452","id":"PMC_19705452","title":"A stable G-quartet binds to a huntingtin protein fragment containing expanded polyglutamine tracks.","date":"2010","source":"Journal of neuroscience research","url":"https://pubmed.ncbi.nlm.nih.gov/19705452","citation_count":6,"is_preprint":false},{"pmid":"40507844","id":"PMC_40507844","title":"Exploring the Healing Powers of Histatins: From Oral Health to Therapeutics.","date":"2025","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/40507844","citation_count":3,"is_preprint":false},{"pmid":"39396174","id":"PMC_39396174","title":"IN VITRO ANTICANCER ACTIVITY OF HISTATIN-1 COMBINATION WITH CISPLATIN IN HEAD AND NECK CANCER CELL LINES.","date":"2024","source":"Experimental oncology","url":"https://pubmed.ncbi.nlm.nih.gov/39396174","citation_count":2,"is_preprint":false},{"pmid":"36160951","id":"PMC_36160951","title":"High-resolution mapping reveals a Ht3-like locus against northern corn leaf blight.","date":"2022","source":"Frontiers in plant science","url":"https://pubmed.ncbi.nlm.nih.gov/36160951","citation_count":2,"is_preprint":false},{"pmid":"41673772","id":"PMC_41673772","title":"Genome-Edited Maize Expressing Two Native Genes Confers Broad-Spectrum Resistance to Northern Corn Leaf Blight.","date":"2026","source":"Molecular plant pathology","url":"https://pubmed.ncbi.nlm.nih.gov/41673772","citation_count":1,"is_preprint":false},{"pmid":"41223295","id":"PMC_41223295","title":"Assessment of a Protease-Free Method for Body Fluid Identification in Sexual Assault Evidence by Targeted High-Resolution Mass Spectrometry.","date":"2025","source":"Journal of proteome research","url":"https://pubmed.ncbi.nlm.nih.gov/41223295","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":12061,"output_tokens":2023,"usd":0.033264,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8946,"output_tokens":2751,"usd":0.056752,"stage2_stop_reason":"end_turn"},"total_usd":0.090016,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2015,\n      \"finding\": \"The maize Htn1 locus encodes ZmWAK-RLK1, a wall-associated receptor-like kinase with a non-arginine-aspartate (non-RD) kinase domain typical of plant innate immune receptors. TILLING mutants in ZmWAK-RLK1 showed increased susceptibility to northern corn leaf blight, establishing ZmWAK-RLK1 as the causal gene. The extracellular domain is highly diverse between maize genotypes, and an alternative splice variant producing a truncated protein is enriched in susceptible parents.\",\n      \"method\": \"Map-based cloning, TILLING mutant analysis (greenhouse and field), sequence comparison, splice variant analysis\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — map-based cloning plus TILLING loss-of-function mutants with defined disease phenotype, replicated in greenhouse and field\",\n      \"pmids\": [\"26124097\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"ZmWAK-RLK1 (Htn1) localizes to the plasma membrane and its presence reduces pathogen penetration into host tissues. Transcriptome analysis of near-isogenic lines revealed that ZmWAK-RLK1 alters expression of benzoxazinoid (BX) biosynthesis genes, resulting in lower BX content (including DIM2BOA-Glc) when ZmWAK-RLK1 is present. Maize mutants with compromised BX biosynthesis showed increased NCLB resistance, placing Htn1-mediated resistance upstream of or linked to BX metabolite flux.\",\n      \"method\": \"Subcellular localization (plasma membrane), large-scale transcriptome analysis of near-isogenic lines, metabolite quantification, BX biosynthesis mutant analysis\",\n      \"journal\": \"The New phytologist\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization experiment, transcriptomics with metabolite validation, and genetic epistasis via BX mutants, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"30178602\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Ht2 and Ht3 are alleles of ZmWAK-RLK1 (the same gene as Htn1), not independent loci. The ZmWAK-RLK1 variants encoded by Htn1 and Ht2/Ht3 differ by multiple amino acid polymorphisms particularly in the putative extracellular domain, accounting for different race spectra.\",\n      \"method\": \"Map-based cloning, TILLING mutant analysis, diversity/allele analysis\",\n      \"journal\": \"The Plant journal : for cell and molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — map-based cloning plus TILLING loss-of-function, replicates and extends prior cloning work from the same and related labs\",\n      \"pmids\": [\"33533097\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"A Saccharomyces cerevisiae gene named HTN1 encodes a homologue of mammalian RanBP1 (51% sequence identity). The HTN1 protein is proposed to interact with yeast GSP1, GSP2, and PRP20 proteins in an intracellular signalling pathway equivalent to the mammalian RanBP1-Ran/TC4-RCC1 pathway.\",\n      \"method\": \"Gene cloning and sequencing, sequence homology analysis\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — yeast gene identified by sequence homology only; no direct functional/binding experiment performed in this paper for the yeast HTN1 protein\",\n      \"pmids\": [\"7948031\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"In allergic fungal rhinosinusitis (AFRS), HTN1 (histatin 1) expression is the most differentially downregulated antimicrobial peptide gene in sinus mucosa compared to non-AFRS chronic rhinosinusitis. This downregulation is mechanistically linked to a defect in IL-6/STAT3 signaling that impairs TH17/TH22 differentiation, reducing local IL-17/IL-22 levels. Epithelial cells from AFRS patients could restore AMP (including HTN1) expression when stimulated with exogenous IL-22/IL-17, placing HTN1 downstream of IL-22/IL-17 signaling.\",\n      \"method\": \"RT-PCR, fungistasis assay, flow cytometry (TH17/TH22 characterization, STAT signaling), in vitro IL-22/IL-17 stimulation of epithelial cells\",\n      \"journal\": \"The Journal of allergy and clinical immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (RT-PCR, flow cytometry, in vitro stimulation) establishing pathway position, single lab\",\n      \"pmids\": [\"39032670\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"A G-quartet oligonucleotide (G20) physically binds to a huntingtin protein fragment containing an expanded polyglutamine tract (Htn1-171 Q58) and inhibits its aggregation. The interaction was more specific for the Q58 form than the Q23 form, suggesting selectivity for aggregation-prone species.\",\n      \"method\": \"Native gel electrophoresis, AGERA assay, immunoblotting, streptavidin-biotin pull-down, atomic force microscopy\",\n      \"journal\": \"Journal of neuroscience research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (pull-down, AFM, gel assays) in a single study demonstrating direct binding and functional consequence (aggregation inhibition)\",\n      \"pmids\": [\"19705452\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"HTN1 (histatin 1) protein is detectable as a saliva biomarker by targeted high-resolution mass spectrometry, confirming its presence in salivary secretions and enabling its use as a forensic body fluid identification marker.\",\n      \"method\": \"Targeted DDA mass spectrometry proteomics, peptide standard validation, 168-sample forensic validation set\",\n      \"journal\": \"Journal of proteome research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — proteomics detection confirms protein expression/localization in saliva but no direct mechanistic functional experiment performed\",\n      \"pmids\": [\"41223295\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"In maize, HTN1/ZmWAK-RLK1 is a plasma membrane-localized wall-associated receptor-like kinase with a non-RD kinase domain that confers quantitative resistance to northern corn leaf blight by reducing pathogen penetration and modulating benzoxazinoid secondary metabolite biosynthesis downstream of its activation; Ht2 and Ht3 are alleles of the same gene differing in their extracellular domains. In humans, HTN1 encodes histatin 1, a salivary antimicrobial peptide whose expression in sinus epithelial cells is regulated downstream of IL-6/STAT3-dependent TH17/IL-22 signaling, and whose protein product can inhibit HNSCC cell proliferation synergistically with cisplatin.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"The symbol HTN1 in the available corpus maps to multiple unrelated genes across organisms, and the discoveries fragment into at least three distinct proteins. The best-evidenced cluster describes the maize Htn1 locus, which encodes ZmWAK-RLK1, a plasma membrane-localized wall-associated receptor-like kinase with a non-RD kinase domain typical of plant innate immune receptors; loss-of-function TILLING mutants increase susceptibility to northern corn leaf blight, establishing it as the causal resistance gene [#0]. ZmWAK-RLK1 reduces pathogen penetration into host tissue and reprograms benzoxazinoid (BX) secondary metabolite biosynthesis, lowering BX content including DIM2BOA-Glc, with BX-biosynthesis mutants themselves showing increased resistance, linking Htn1-mediated defense to BX metabolite flux [#1]. Ht2 and Ht3 are allelic variants of this same gene that differ in their extracellular domains and thereby confer distinct race spectra [#2]. Separately, the human HTN1 entries describe histatin 1, a salivary antimicrobial peptide detectable in saliva by mass spectrometry [#6] whose epithelial expression in allergic fungal rhinosinusitis is downregulated downstream of IL-6/STAT3-dependent TH17/TH22 signaling and is restored by exogenous IL-22/IL-17 stimulation [#4]. A yeast gene also named HTN1, identified only by sequence homology to mammalian RanBP1, and a huntingtin fragment study using the Htn label, are unrelated to these and to each other [#3, #5]. Because these clusters describe fundamentally different proteins, no single unified mechanism can be synthesized; each is summarized within its own evidence cluster above.\",\n  \"teleology\": [\n    {\n      \"year\": 1994,\n      \"claim\": \"An early entry under the HTN1 symbol described a yeast gene homologous to mammalian RanBP1, raising the possibility of a Ran-pathway signalling role.\",\n      \"evidence\": \"Gene cloning, sequencing, and sequence homology analysis in S. cerevisiae\",\n      \"pmids\": [\"7948031\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct binding or functional experiment performed for the yeast protein\", \"Interaction with GSP1/GSP2/PRP20 inferred from homology only\", \"Unrelated to the maize and human HTN1 entries\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"A study using the Htn1 label addressed whether a G-quartet oligonucleotide could bind and inhibit aggregation of an expanded-polyglutamine huntingtin fragment, with selectivity for the aggregation-prone form.\",\n      \"evidence\": \"Native gel, AGERA, pull-down, and atomic force microscopy on Htn1-171 Q58 versus Q23 fragments\",\n      \"pmids\": [\"19705452\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Concerns a huntingtin polyQ fragment, not the salivary or maize HTN1 gene products\", \"In vitro binding only; cellular relevance not established\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Map-based cloning resolved which gene underlies maize Htn1 northern corn leaf blight resistance, identifying ZmWAK-RLK1 and establishing it as a non-RD receptor-like kinase causal for the phenotype.\",\n      \"evidence\": \"Map-based cloning, TILLING loss-of-function mutants tested in greenhouse and field, splice-variant analysis\",\n      \"pmids\": [\"26124097\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Ligand/elicitor recognized by the extracellular domain unknown\", \"Kinase substrates and downstream signalling partners not identified\", \"Mechanism of the truncated splice variant's effect unresolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Localization and near-isogenic-line transcriptomics defined how ZmWAK-RLK1 acts, placing it at the plasma membrane and linking resistance to reduced pathogen penetration and altered benzoxazinoid metabolite flux.\",\n      \"evidence\": \"Subcellular localization, transcriptome profiling of NILs, metabolite quantification, and BX-biosynthesis mutant epistasis\",\n      \"pmids\": [\"30178602\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct biochemical link between kinase activity and BX gene regulation not established\", \"Whether BX changes are cause or consequence of reduced penetration unresolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Allele analysis resolved whether Ht2 and Ht3 are independent resistance loci, showing they are variants of the same ZmWAK-RLK1 gene differing in the extracellular domain and accounting for distinct race specificities.\",\n      \"evidence\": \"Map-based cloning, TILLING mutants, and diversity/allele comparison\",\n      \"pmids\": [\"33533097\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of extracellular-domain race specificity not determined\", \"No direct recognition assay for any race-specific elicitor\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Work on human histatin 1 positioned HTN1 within mucosal immunity, showing its epithelial expression is downregulated in allergic fungal rhinosinusitis downstream of defective IL-6/STAT3-driven TH17/TH22 signaling and restorable by IL-22/IL-17.\",\n      \"evidence\": \"RT-PCR, fungistasis assay, flow cytometry for TH17/TH22 and STAT signaling, in vitro IL-22/IL-17 epithelial stimulation in patient samples\",\n      \"pmids\": [\"39032670\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct transcriptional regulators of HTN1 downstream of IL-22/IL-17 not mapped\", \"Antimicrobial mechanism of the peptide itself not assayed here\", \"Single-lab patient cohort\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Targeted proteomics confirmed histatin 1 protein in saliva, validating its expression and enabling forensic body-fluid identification.\",\n      \"evidence\": \"Targeted DDA mass spectrometry with peptide standards and a 168-sample forensic validation set\",\n      \"pmids\": [\"41223295\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Detection only; no functional mechanism tested\", \"Does not address regulation or activity of the peptide\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The HTN1 symbol in this corpus conflates several biologically unrelated entities, and no cross-cutting mechanism unifies the maize receptor kinase, human salivary histatin, yeast RanBP1 homologue, and huntingtin-fragment entries.\",\n      \"evidence\": \"Internal incoherence across the timeline clusters\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Reader must disambiguate which organism/gene each finding refers to\", \"No shared molecular pathway links the clusters\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": []}\n    ],\n    \"complexes\": [],\n    \"partners\": [],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":4,"faith_total":5,"faith_pct":80.0}}