FOXN1

Summary: FOXN1 associates with regulatory chromatin as a transcription factor.

Reason: The original ISA chromatin classification is consistent with a sequence-specific transcription factor acting on genomic regulatory regions. Human FOXN1 directly binds defined regulatory DNA in PMID:31914405; its genomic occupancy analyses are explicitly mouse ChIP-seq, not direct human chromatin imaging. Retain the unrestricted chromatin association as part of the established transcriptional role while keeping this assay and species distinction explicit.

Summary: FOXN1 recognizes sequence-specific RNA polymerase II regulatory DNA.

Reason: The original IBA is grounded in a literal positive IBD at PTN000930751 on the human FOXN1 lineage. Human FOXN1 residues 270–366 directly recognize an FHL motif from the mouse Psmb11 promoter in PMID:31914405; longer human preparations also bind mouse Psma7 regulatory probes. Together with the rodent promoter-reporter experiments, these support the more specific RNA polymerase II cis-regulatory sequence-binding term GO:0000978. The promoter DNA is mouse, the structural protein is human, and the intended full-length bacterial preparation was truncated at residue 614; no natural isoform or direct human-cell reporter assay is inferred.

Proposed replacements: RNA polymerase II cis-regulatory region sequence-specific DNA binding

Summary: The inherited transcription-factor activity is retained through a more specific activator activity.

Reason: The actual PTHR46721 tree and alignment place the human sequence below the positive PTN000930751 IBD for this function. This is a sound phylogenetic assertion, rather than a weak pairwise transfer. GO:0001228, retained from the existing activator annotation, is an is_a child of GO:0000981 and better describes the supported positive transcriptional role. The granularity judgment does not reject the IBD or alter its donors.

Summary: The transcription-factor classification is covered by the specific activator activity.

Reason: The original tfclass:3.3.1 ISA classification agrees with the forkhead protein and its experimentally supported DNA-binding and activating functions. The existing GO:0001228 activator annotation is an is_a descendant of GO:0000981. Apply the same gene-level granularity judgment as for the independent IBA, without treating a different evidence method as a different biological function.

Summary: FOXN1 is a DNA-binding transcriptional activator.

Reason: The exact mouse Q61575 donor has IDA and IMP annotations to this same term from PMID:9108066. Its selected original Methods and Results show sequence-specific mouse Whn binding and activation of a binding-site reporter in BHK cells. PMID:8790387 separately maps a transcriptional activation region using mouse and pufferfish GAL4 fusions. Direct human FOXN1–DNA structural and biochemical evidence in PMID:31914405 supports conservation of the binding function. Retain the human orthology assertion as a core capacity, while distinguishing the rodent activation experiments from the human binding experiments.

Summary: FOXN1-dependent thymic epithelial signals support T-cell lineage commitment.

Reason: The original mouse Q61575 donor traces to PMID:24184560, whose marrow niche and progenitor results do not isolate irreversible T-lineage commitment. Independently, PMID:27548434 directly identifies Dll4 as a Foxn1 target in thymic epithelial cells and shows reduced early T-lineage progenitors with increased thymic B cells in the hypomorphic mouse model. Together, direct control of a lineage-instructive niche signal and the T/B-lineage shift support a non-core commitment role. This is an inference from epithelial instruction and lineage output, not a claim that the experiments tracked an individual progenitor through irreversible choice or that FOXN1 acts within the T cell. The original human orthology assertion and donor reference remain unchanged.

Summary: The generic DNA-binding transcription-factor class is covered by the specific activator activity.

Reason: The original IPR001766 and IPR030456 mappings are compatible with FOXN1. GO:0001228 is an is_a descendant of GO:0003700 through GO:0000981 and provides the supported RNA polymerase II activator specificity. Retain the original InterPro source context in provenance; the broader term is not biologically contradicted.

Summary: FOXN1 has a screen-supported interaction with MAPKBP1.

Reason: The exact O15353–O60336 records support association with the MAPKBP1 scaffold. The screen does not establish that FOXN1 performs a MAPK scaffold or signaling-adaptor function, so the interaction is retained as non-core rather than converted into such an activity.

Summary: FOXN1 interacts with the tested TRAPPC6A isoform.

Reason: The exact partner is O75865-2, TRAPPC6A isoform 2. Association with a TRAPP-complex component does not demonstrate vesicle tethering or membrane traffic by FOXN1. Retain the interaction and the tested partner isoform as a non-core context; do not generalize it to every TRAPPC6A product.

Summary: FOXN1 has a screen-supported interaction with cytidine deaminase.

Reason: The exact P32320 partner is cytidine deaminase. No catalytic, substrate or nucleotide-metabolism role for FOXN1 was established by these interaction records. An enzyme-binding label would add little functional specificity in this context, so retain the positive association as non-core.

Summary: FOXN1 binds the RNA polymerase II transcription factor HOXA1 in the interaction screen.

Reason: The exact partner P49639 is reviewed human HOXA1, a homeobox DNA-binding transcription factor. The retained official record explicitly classifies HOXA1 with GO:0000981 and GO:0001228, supporting GO:0061629 RNA polymerase II-specific DNA-binding transcription factor binding as a refinement of the existing interaction. The class assignment does not establish a joint target, regulatory direction or transcriptional cofactor activity for FOXN1 in this pair.

Proposed replacements: RNA polymerase II-specific DNA-binding transcription factor binding

Summary: FOXN1 binds a tested isoform of the transcriptional corepressor TLE5.

Reason: The exact partner Q08117-2 is TLE5/AES isoform 2. The reviewed UniProt record identifies TLE5 as a transcriptional corepressor; this isoform has a recorded N-terminal alternative sequence, which is preserved as the assayed partner identity. GO:0001222 transcription corepressor binding expresses the partner class without claiming that this interaction recruits repression at a FOXN1 target or converts FOXN1 itself into a corepressor.

Proposed replacements: transcription corepressor binding

Summary: FOXN1 has a screen-supported interaction with TRAF2.

Reason: The exact Q12933 partner is TRAF2, which participates in ubiquitin-ligase and signaling assemblies. The interaction records do not show FOXN1 ubiquitination, regulation of TRAF2 catalysis or a FOXN1 signaling-adaptor role. Preserve the positive association as non-core; a generic enzyme-binding refinement would not resolve its functional role.

Summary: FOXN1 has a screen-supported interaction with PIN1.

Reason: The exact Q13526 partner is the peptidyl-prolyl isomerase PIN1. These records establish the screened association but do not identify a FOXN1 phosphosite, isomerized bond or catalytic consequence. Keep the interaction as non-core without inventing a substrate or isomerase-regulatory function.

Summary: FOXN1 binds the RNA polymerase II transcription factor LHX8 in the screen.

Reason: The exact Q68G74 partner is LHX8, with a reviewed homeobox DNA-binding domain and transcription-factor classification. The retained official GO:0000981 classification supports the more specific GO:0061629 RNA polymerase II transcription-factor binding class. Neither the class refinement nor the binary-screen result establishes transcriptional cooperation, a common target or an endogenous developmental complex.

Proposed replacements: RNA polymerase II-specific DNA-binding transcription factor binding

Summary: FOXN1 associates with TSSK1B in two assay systems.

Reason: The exact Q9BXA7 partner is the serine/threonine kinase TSSK1B. In addition to the linked yeast two-hybrid records, this pair has a distinct MAPPIT record in human HEK293T cells (EBI-25292441; IM-25472-162516). This strengthens the interaction evidence but does not show FOXN1 phosphorylation or a kinase-regulatory function. Retain the positive association as non-core instead of inferring a functional kinase-binding specialization.

Summary: FOXN1 interacts with the tested SPATC1L isoform.

Reason: The exact partner Q9H0A9-2 is SPATC1L isoform 2. The retained reviewed record does not provide a sufficiently informative molecular partner class for a functional refinement. Preserve the positive interaction and exact isoform without inferring a centrosomal or germ-cell role for FOXN1.

Summary: FOXN1 binds the RNA polymerase II transcription-factor family member DMRT3 in the screen.

Reason: The exact Q9NQL9 partner is DMRT3, with a DM DNA-binding domain and a reviewed, partly similarity-supported transcription-factor classification. The retained official GO:0000981 classification supports GO:0061629 as the bounded RNA polymerase II transcription-factor binding refinement. It does not assign DMRT3-dependent transcription, neuronal specification or sexual development to FOXN1.

Proposed replacements: RNA polymerase II-specific DNA-binding transcription factor binding

Summary: FOXN1 has a screen-supported interaction with CDC23.

Reason: The exact Q9UJX2 partner is CDC23, a structural component of the APC/C ubiquitin-ligase complex. Membership in that enzyme complex does not establish that isolated CDC23 is the catalytic enzyme or that FOXN1 regulates APC/C. Retain the association as non-core without an unsupported enzyme-binding or cell-cycle function.

Summary: FOXN1 performs its transcriptional function in the nucleus.

Reason: The is_active_in nucleus IBA joins a literal positive PTN000930751 IBD on the verified human lineage. Nuclear activity is consistent with the DNA-binding transcriptional role and the selected rodent localization and activation experiments. The original relation, node and source are retained.

Summary: FOXN1 is a nuclear protein.

Reason: The UniProt subcellular-location mapping SL-0191 agrees with the nuclear transcription-factor role and with the independently retained nucleus IBA. Keep the original located_in relation distinct from the is_active_in assertion; the electronic evidence does not warrant a different gene-level compartment judgment.

Summary: The historical nucleus annotation agrees with FOXN1's nuclear function.

Reason: The selected original PMID:10767081 experiments localize tagged full-length mouse Whn in human HeLa cells; an R320C DNA-binding mutant retains nuclear staining. Engineered split constructs also contain an added NLS, which is not independent evidence for native localization. Retain the human TAS nucleus claim because the nuclear gene-level function is independently established, while preserving the rodent construct and original reference rather than relabeling it as a direct human localization experiment.

Summary: Positive RNA polymerase II transcriptional regulation captures the established regulatory role more specifically.

Reason: The InterPro-derived broad transcription-regulation assertion agrees with FOXN1 biology. The retained GO:0045944 annotation is an is_a descendant of GO:0006355 and adds the supported positive direction and RNA polymerase II context. Mouse binding-site reporters and activation-domain experiments support that direction; direct human DNA-binding evidence is complementary, not a human-cell transcription assay.

Summary: The inherited transcription-regulation function is represented by the specific positive-regulation term.

Reason: This IBA has a verified positive IBD at PTN000930751 on the actual human lineage. The retained GO:0045944 is an is_a child of GO:0006357. Prefer that supported directional term at gene level while preserving the complete phylogenetic assertion, its placement and its experimental grounding.

Summary: The original reporter work supports positive transcriptional regulation.

Reason: Selected original Methods and Results of PMID:10767081 use mouse Whn cDNA CAA57279 in human HeLa cells, induce human hair-keratin RNA and map binding and activation requirements. They support the positive regulatory capacity represented by retained GO:0045944, an is_a child of this term. The human host is not evidence that the expressed protein was human, and the engineered FKBP split-protein rescue is not a natural isoform or native dimerization assay. Keep the original TAS reference unchanged.

Summary: The direct defense-response scope of the historical assertion remains unverified.

Reason: The authentic abstract of PMID:7969402 links nude Foxn1 mutations to hair and thymic phenotypes. GO:0006952 describes a response triggered by a foreign body or injury, rather than constitutive thymus development alone. The accessible material does not resolve which such response was attributed to FOXN1, and the full original paper was not recovered in this bounded reading. Preserve the TAS assertion and its uncertainty; do not label the citation wrong or infer that the unread paper lacks relevant evidence.

Summary: FOXN1 contributes to epidermal development through its epithelial differentiation program.

Reason: PMID:10767081 supports epithelial differentiation and keratin-gene regulation, using mouse Whn in HeLa cells and rodent skin comparisons. Epidermis development retains informative tissue-level scope alongside the more specific core keratinocyte differentiation activity. GO:0030216 reaches GO:0008544 through is_a epidermal cell differentiation, then part_of epidermis development; this mixed path does not make the organ-level contribution dispensable. Retain the original TAS assertion as a non-core developmental context, with its rodent construct limits explicit.

Summary: FOXN1-dependent epithelial development contributes to organ morphology.

Reason: The nude hair and thymus phenotypes reported in the authentic PMID:7969402 abstract are consistent with FOXN1-dependent organ development; later rodent epithelial perturbation and human clinical findings independently support that broad capacity. Keep this historical TAS assertion as non-core with the original-paper full-text limit explicit. The checked GO:0097536 path does not reach GO:0009887 through is_a or part_of, so no unsupported ancestor-based redundancy claim is made.

Summary: FOXN1 affects hematopoietic production through a specialized niche in the mouse model.

Reason: The exact mouse donor is an involved_in IMP assertion from PMID:24184560. Its actual transfer experiment shows increased donor MPP/HSC ratios in the Foxn1-transgenic host, and other assays support maintenance of progenitor production with age. Sorted HSC and MPP lacked Foxn1; a separate CD45-positive EpCAM-positive CD138-negative population expressed Foxn1 and Dll4. Retain the contextual hematopoietic role as non-core without claiming FOXN1 activity inside HSC/MPP, direct Dll4 targeting, or that the nonsignificant donor CIP/CTP trend was a demonstrated effect.

Summary: FOXN1 supports keratinocyte differentiation.

Reason: The exact rat A0A8I6GMI6 donor contains an involved_in IMP assertion from PMID:8790387 as well as a separate acts_upstream_of_or_within ISO row. The original rat allele and hair phenotype, rodent activation-domain experiments and mouse Whn induction of keratin genes in PMID:10767081 support the conserved differentiation role. Preserve the distinct donor relations and the human orthology annotation; neither HeLa host cells nor a human promoter turn the tested rodent protein into a human construct. Together these findings support a characteristic FOXN1 epithelial differentiation program.

Summary: FOXN1 promotes epithelial differentiation in a context-dependent program.

Reason: The authentic PMID:24383669 abstract reports endogenous FOXN1 up-regulation and epithelial-marker responses in human NT2/D1 and H9 models. This agrees with the independently supported epithelial differentiation role from rodent perturbation and human loss-of-function evidence, so retain the unrestricted gene-level capacity. The exact original gain-of-function construct and full endpoint Methods were not recovered; no unseen assay is certified. The reported FOXN1 3-prime-UTR luciferase experiment tests miRNA regulation of FOXN1, not FOXN1 sequence-specific transcription-factor activity. The NT2/D1/H9 differentiation setting is retained as a non-core context; characteristic keratinocyte and thymic epithelial programs are represented separately in the core synthesis.

Summary: The precise T-cell homeostasis process remains unresolved after reassessment.

Reason: The original Q61575 donor traces to PMID:24184560, which establishes altered marrow progenitor pools and a T-lineage-supporting niche. PMID:27548434 adds direct thymic epithelial target regulation and thymocyte differentiation and selection defects. These findings establish developmental supply and maturation, but neither inspected study measures the balance of proliferation and elimination that maintains a T-cell population over time, as specified by GO:0043029. Reduced cell numbers or steady-state Foxn1 expression do not resolve that endpoint. Retain UNDECIDED for this process while accepting the independently supported epithelial and selection functions.

Summary: Sequence-specific DNA binding is covered by the more specific regulatory-region binding refinement.

Reason: The integrated donor and domain assertion is biologically sound: the mouse donor has direct binding evidence in PMID:9108066, and PMID:31914405 directly resolves human FOXN1 bound to a defined regulatory motif. The proposed GO:0000978 refinement of the existing cis-regulatory binding row is an is_a descendant of GO:0043565. Mark this unrestricted term as too general, without weakening its source or overstating the human construct as intact full-length protein.

Summary: FOXN1 positively regulates RNA polymerase II transcription.

Reason: The exact Q61575 IMP donor in PMID:9108066 is supported by binding-site-dependent reporter activation using mouse Whn and by loss of activation after disruption of DNA recognition or the activation region. PMID:10767081 independently demonstrates induction of endogenous human keratin transcripts by mouse Whn in HeLa cells. These support the conserved positive transcriptional role; the human IEA source and donor identities remain unchanged, and the host species is not confused with construct species.

Summary: FOXN1-dependent thymic epithelium influences vascular morphogenesis.

Reason: The exact mouse donor is an involved_in IMP assertion from PMID:19853842. Its authentic abstract reports absent endothelial invasion and altered VEGF-positive mesenchymal cells in nude thymic rudiments. Separately read Results and captions from PMID:23750244 show delayed vascular entry in a hypomorphic mouse model and explicitly allow non-cell-autonomous epithelial signaling or indirect organ-size effects. Retain an organ-context vascular role as non-core, not endothelial FOXN1 activity or direct VEGF targeting. The original PMID:19853842 Methods remain inaccessible; the distinct auxiliary source is not substituted for it.

Summary: FOXN1 directs epithelial programs essential for thymus development.

Reason: The exact rat donor has an involved_in IMP assertion from PMID:8790387, distinct from its broader acts_upstream_of_or_within ISO assertion. Rodent nude genetics and epithelial perturbations, together with human clinical thymic hypoplasia, support thymus development as a characteristic FOXN1 role. Thymus epithelial morphogenesis is part_of thymus development, but it does not exhaust the organ-level developmental context. Retain this informative process as core while representing the narrower epithelial program in the core-function synthesis; no thymocyte-intrinsic FOXN1 activity is inferred.

Summary: FOXN1 promotes normal hair-follicle development.

Reason: The exact mouse donor is an involved_in IMP assertion from PMID:21109991. Original conditional deletion experiments affect hair follicles as well as thymic epithelial compartments, supporting a positive developmental requirement. Retain this tissue-context role as non-core. The human K14 sequence is the transgene promoter driving mouse experiments, not a human FOXN1 functional construct; the experiments do not establish every downstream hair-follicle step as a direct FOXN1 target.

Summary: A thymic recruitment mechanism is supported, but the specific immigration endpoint remains unresolved.

Reason: The same-term mouse donor traces to PMID:19853842, whose original Methods and Results remain inaccessible. Independent PMID:27548434 establishes Foxn1-dependent Ccl25 regulation and reduced early thymic progenitors, supporting a niche recruitment mechanism. Those measurements do not separate immigration from retention, survival or subsequent differentiation. The distinct PMID:23750244 hypomorph has delayed vascular entry but normal initial lymphoid progenitor immigration at E11.5; later cell abundance is a separate endpoint. The evidence therefore does not yet resolve the precise migration process or refute the original null-model annotation. Retain UNDECIDED without requiring T-cell-intrinsic FOXN1 activity.

Summary: FOXN1 is required for organization of thymic epithelium.

Reason: The exact mouse donor traces to PMID:21109991. Its original conditional deletion experiments directly assess medullary epithelial architecture, mature epithelial markers and cyst expansion, alongside reduced thymocyte numbers. This supports the epithelial morphogenesis context rather than merely a secondary immune phenotype. Retain the human orthology assertion as a core epithelial process, preserving prenatal versus postnatal recombination limits and distinguishing the human K14 promoter from the mouse Foxn1 protein.

Summary: FOXN1-dependent thymic epithelial programs regulate positive T-cell selection.

Reason: The original mouse donor reference PMID:24184560 establishes marrow niche and progenitor effects but did not yield a verified positive-selection endpoint in the inspected material. Independent PMID:27548434 directly measures reduced CD69/TCR-defined positive selection and altered CD4/CD8 maturation in a hypomorphic Foxn1 mouse model. It also links Foxn1 occupancy and transcription to Psmb11 and Cd83, with promoter-motif perturbations and comparisons to the corresponding deficient mice. These selection endpoints support the conserved non-core regulatory role beyond DNA binding alone. The authors state that target-gene reconstitution is still needed to quantify how much Psmb11 and Cd83 mediate the phenotype; complete mechanistic rescue is not established. The original human assertion and donor identity remain intact.