{"gene":"TEN1","run_date":"2026-06-10T10:51:54","timeline":{"discoveries":[{"year":2001,"finding":"Yeast Ten1 physically associates with both Stn1 and Cdc13, forming a trimeric complex at telomeres. A binding defect between Stn1-13 and Ten1 was responsible for the long telomere phenotype of stn1-13 cells. Temperature-sensitive ten1 mutants accumulated single-stranded DNA at telomeric regions and arrested at G2/M via activation of the Rad9-dependent DNA damage checkpoint, establishing Ten1's role in telomere end protection and length regulation.","method":"Two-hybrid interaction, genetic epistasis, temperature-sensitive mutant analysis, checkpoint activation assays","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal two-hybrid, multiple mutant alleles with distinct phenotypes, checkpoint pathway placement, replicated across follow-up studies","pmids":["11230140"],"is_preprint":false},{"year":2007,"finding":"Fission yeast (S. pombe) Stn1 and Ten1 are orthologs that are essential for chromosome end protection. Stn1 and Ten1 associate with each other but not with Pot1, indicating they form a separate complex from Pot1 at fission yeast telomeres. Both proteins localize at telomeres in a manner correlating with the length of the ssDNA overhang, and structural profiling detects OB-fold domains in both.","method":"Co-immunoprecipitation, telomere localization assays, bioinformatics structural prediction, genetic analysis of null mutants","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal co-IP, direct localization experiments with functional consequence, independent from budding yeast work","pmids":["17715303"],"is_preprint":false},{"year":2009,"finding":"Mammalian TEN1, together with CTC1 and STN1, forms an RPA-like CST complex that binds single-stranded DNA with high affinity in a sequence-independent manner. The complex associates with a fraction of telomeres consistently throughout the cell cycle including in quiescent cells and Pot1-knockdown cells. STN1 knockdown increased single-stranded G-strand telomeric DNA abundance, establishing the CST complex role in protecting telomeres independently of the Pot1 pathway.","method":"Co-immunoprecipitation, ssDNA binding assays, knockdown (siRNA), fluorescence in situ hybridization","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (Co-IP, ssDNA binding, knockdown with FISH readout), foundational paper replicated across species","pmids":["19854130"],"is_preprint":false},{"year":2009,"finding":"Crystal structure of Candida tropicalis Stn1N complexed with Ten1 demonstrates an Rpa2N-Rpa3-like complex, where OB folds of the two components pack against each other through interactions between two C-terminal helices. The C-terminal domain of S. cerevisiae Stn1 comprises two WH motifs analogous to Rpa2. The fission yeast S. pombe Stn1N-Ten1 complex exhibits virtually identical architecture. Mutations disrupting the Stn1-Ten1 interaction induce telomere uncapping and abolish telomere localization of Ten1.","method":"X-ray crystallography, mutational analysis, telomere localization assays","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structures from multiple organisms combined with functional mutagenesis and localization assays","pmids":["20008938"],"is_preprint":false},{"year":2009,"finding":"Temperature-sensitive ten1 mutants in S. cerevisiae display elongated telomeres at permissive temperature and accumulate extensive telomeric single-stranded DNA at non-permissive conditions. Cdk1 activity is required to generate these single-stranded regions, and deleting EXO1 nuclease partially suppresses ten1-ts growth defects. Despite Cdc13 remaining bound at telomeres in ten1-ts cells, telomere end protection is lost, establishing that Cdc13 relies on Ten1 to execute its essential capping function. Ten1 also promotes de novo telomere addition.","method":"Temperature-sensitive mutant analysis, genetic epistasis (cdk1, exo1 deletion), chromatin immunoprecipitation, fluorescence microscopy of Rad52-YFP foci","journal":"Genetics","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal genetic and cell biology approaches in a single focused study","pmids":["19752213"],"is_preprint":false},{"year":2010,"finding":"A predicted alpha-helix in the N-terminal OB domain of S. cerevisiae Stn1 is required for interaction with Ten1, analogous to the Rpa2-Rpa3 interface in RPA. Mutations in a hydrophobic surface of the Stn1 alpha-helix eliminated Stn1-Ten1 association. Allele-specific suppression of stn1-L164D by ten1-D138Y restored the Stn1-Ten1 interaction, defining a direct Stn1-Ten1 interface.","method":"Rpa2-OB(Stn1) chimera analysis, site-directed mutagenesis, allele-specific suppression genetics, co-immunoprecipitation","journal":"Genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — allele-specific suppression plus mutagenesis plus chimeric protein analysis provides strong mechanistic evidence for the interface","pmids":["20157006"],"is_preprint":false},{"year":2011,"finding":"Xenopus laevis CST (xCST), including xTen1, forms an ssDNA-binding complex with moderate preference for G-rich sequences. Immunodepletion of xStn1 from egg extracts did not affect chromosomal DNA replication from sperm nuclei but specifically compromised DNA synthesis on ssDNA templates; this defect was rescued by pre-primed ssDNA templates, establishing that xCST is involved in the priming step on ssDNA template rather than being a general replication factor.","method":"Immunodepletion from Xenopus egg extracts, in vitro DNA replication assays on ssDNA templates, ssDNA binding assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — reconstituted in vitro priming assay with immunodepletion rescue, single lab but multiple orthogonal approaches","pmids":["22086929"],"is_preprint":false},{"year":2013,"finding":"Crystal structure of the human Stn1-Ten1 (hStn1-Ten1) complex reveals that hStn1 consists of an OB domain and tandem C-terminal wHTH motifs, while hTen1 consists of a single OB fold. Contacts between OB domains mediate complex formation strikingly similar to RPA. The hStn1-Ten1 complex exhibits non-specific ssDNA binding activity primarily dependent on hStn1. Cells expressing hStn1 mutants defective for dimerization with hTen1 display elongated telomeres and telomere uncapping defects, demonstrating that the telomeric function of hCST is hTen1-dependent.","method":"X-ray crystallography, ssDNA binding assays, cell-based mutant expression, telomere length analysis, telomere FISH","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure of human complex combined with structure-guided mutagenesis and functional cell-based validation","pmids":["23826127"],"is_preprint":false},{"year":2013,"finding":"Human TEN1 depletion causes increased multitelomere FISH signals (indicative of telomere duplex replication defects) and telomere loss without increased deprotection, recombination, or T-circle release. TEN1 depletion delays G-overhang shortening in late S/G2 but does not affect overhang elongation in mid-S phase, indicating a role in C-strand fill-in but not telomerase regulation. TEN1 depletion also reduces genome-wide replication restart after fork stalling, similar to STN1 depletion.","method":"siRNA knockdown, telomere FISH, BrdU incorporation assay for replication restart, G-overhang analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal assays (FISH, replication restart, overhang analysis) in human cells, focused on TEN1 specifically","pmids":["24025336"],"is_preprint":false},{"year":2013,"finding":"In budding yeast, Cdk1 phosphorylates Stn1 at Thr223 and Ser250 both in vitro and in vivo. These phosphorylation events are essential for the stability of CST (Cdc13-Stn1-Ten1) complexes at telomeres. By controlling the timing of Cdc13 and Stn1 phosphorylations during the cell cycle, Cdk1 regulates the temporal recruitment of telomerase complexes versus CST complexes to telomeres to facilitate telomere maintenance.","method":"In vitro kinase assays, in vivo phosphorylation mapping, telomere chromatin immunoprecipitation, cell cycle synchronization","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — in vitro kinase assay combined with in vivo phosphorylation mapping and ChIP, single lab with multiple orthogonal methods","pmids":["24164896"],"is_preprint":false},{"year":2014,"finding":"The CDC13-STN1-TEN1 (CST) complex from Candida glabrata stimulates primase-Pol α (PP) activity by augmenting primase activity and primase-to-polymerase switching, simultaneously shortening the RNA primer and lengthening the DNA product. CST does not enhance isolated DNA polymerase activity alone. The Stn1 subunit alone is sufficient for PP stimulation. Both the N-terminal OB fold and C-terminal winged-helix domains of Stn1 bind the Pol12 subunit of PP and stimulate PP activity.","method":"In vitro primase-polymerase activity assays with purified complexes, domain deletion/mutagenesis, binding assays","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstituted in vitro with purified components, domain-level mutagenesis defining mechanism, specific for Stn1 within the CST complex","pmids":["25503194"],"is_preprint":false},{"year":2014,"finding":"In S. cerevisiae, the requirement for Cdc13 (but not for Stn1 or Ten1) can be bypassed when both the DNA damage response and nonsense-mediated mRNA decay (NMD) pathways are inactivated. Disabling NMD alters stoichiometry of CST components at telomeres and permits Stn1 to bind telomeres in the absence of Cdc13, supporting a model that Stn1 and Ten1 can function in a Cdc13-independent manner.","method":"Genetic epistasis, telomere chromatin immunoprecipitation, double mutant bypass analysis","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — epistasis combined with ChIP showing Stn1 telomere binding in cdc13 mutant, single lab","pmids":["24835988"],"is_preprint":false},{"year":2017,"finding":"The human CST complex (CTC1-STN1-TEN1) forms a functional complex that localizes in ALT-associated PML bodies (APBs) in ALT cancer cells. CST suppression in ALT cells induces telomere fragility, elevates telomeric DNA recombination, diminishes C-circles and t-circles abundance, and causes multinucleation, establishing a role for CST including TEN1 in ALT telomere maintenance.","method":"siRNA knockdown, immunofluorescence co-localization, telomere FISH, C-circle assay, flow cytometry","journal":"Experimental cell research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple readouts in ALT cells, single lab, no specific TEN1 mechanistic dissection from STN1/CTC1","pmids":["28366536"],"is_preprint":false},{"year":2018,"finding":"In fission yeast, the Stn1-Ten1 complex restricts telomerase action via a SUMO-interacting motif (SIM) in the C-terminal part of Stn1. The SIM mediates interaction with SUMOylated Tpz1 (TPP1 ortholog). Point mutations in the SIM (Stn1-226) lead to telomere elongation, impair Stn1-Ten1 recruitment to telomeres, and enhance telomerase binding. Stn1-Ten1 also promotes DNA synthesis at telomeres to limit ssDNA accumulation and functions in replication of telomeric and subtelomeric regions in a Taz1-independent manner.","method":"Mutagenesis (SIM mutations), co-immunoprecipitation, ChIP, telomere length analysis, genetic analysis of replication mutants","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 2 / Strong — structure-guided mutagenesis, reciprocal Co-IP, ChIP with functional consequences, multiple orthogonal methods in one study","pmids":["29774234"],"is_preprint":false},{"year":2018,"finding":"In human colon cancer cells, CTC1-STN1 (without TEN1) is sufficient to limit telomerase action and prevent G-overhang overextension; CTC1-/- cells exhibit overhang elongation whereas TEN1-/- cells do not. However, TEN1 is essential for C-strand synthesis, and TEN1-/- cells exhibit progressive telomere shortening. DNA binding analysis indicates that CTC1-STN1 retains ssDNA affinity but TEN1 stabilizes this binding, enabling proper engagement of Pol α for C-strand synthesis.","method":"CRISPR knockout of individual subunits, G-overhang analysis, telomere length measurements, ssDNA binding assays","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — CRISPR KO of each subunit separately with multiple orthogonal readouts, dissecting subunit-specific functions","pmids":["30026550"],"is_preprint":false},{"year":2019,"finding":"In S. cerevisiae, Ten1 (as part of the CST complex) regulates RNA polymerase II transcription. Genetic interactions between TEN1 and transcription regulators were found, and molecular assays showed Ten1 regulates the occupancies of RNA Pol II and the Spt5 elongation factor within transcribed genes. Ten1, Cdc13, and Stn1 all physically associate with Spt5, identifying Spt5 as the target of CST in transcription regulation. CST also physically associates with Hmo1.","method":"Genetic interaction analysis, ChIP (RNA Pol II and Spt5 occupancy), co-immunoprecipitation with Spt5","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and Co-IP in a single lab, novel function for CST in transcription with molecular mechanism partially defined","pmids":["31006804"],"is_preprint":false},{"year":2019,"finding":"In fission yeast, a conserved SWSSS motif in Tpz1 (adjacent to Lys242 SUMOylation site) works redundantly with Lys242 SUMOylation to promote Stn1-Ten1 binding at telomere and sub-telomere regions. This binding protects against SSA-dependent telomere fusions and prevents telomerase accumulation at telomeres.","method":"Mutagenesis of SWSSS motif and Lys242, co-immunoprecipitation, telomere ChIP, telomere southern blot","journal":"Communications biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — structure-guided mutagenesis and ChIP showing Stn1-Ten1 recruitment depends on Tpz1, single lab","pmids":["31396577"],"is_preprint":false},{"year":2020,"finding":"In single-linear-chromosome yeast (SY14), deletion of TEN1 (or STN1) leads to a ~29-fold lower frequency of survivors compared to CDC13 deletion, demonstrating that Ten1 and Stn1 have a more stringent requirement than Cdc13 in preventing telomere fusion. CDC13 deletion leads to Rad52-dependent intrachromosome end-to-end fusions, while Stn1/Ten1 loss does not produce fusion at the same frequency.","method":"Gene deletion in single-linear-chromosome yeast, survivor frequency analysis, genetic epistasis with Rad52 and Yku","journal":"eLife","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — quantitative genetic analysis in specialized yeast strain, single lab, dissects subunit-specific roles","pmids":["32755541"],"is_preprint":false},{"year":2023,"finding":"In fission yeast, Pot1 promotes telomere DNA replication by recruiting the Stn1-Ten1 complex (and Pol α-primase) to telomeres via Tpz1. In pot1-1 temperature-sensitive mutants, Stn1 recruitment to telomeres is reduced and ssDNA accumulates; overexpression of Stn1 rescues telomere loss and cell viability, placing Ten1/Stn1 downstream of Pot1-Tpz1 in the lagging-strand synthesis pathway.","method":"Temperature-sensitive mutant analysis, ChIP, overexpression rescue, telomere Southern blot","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and genetic rescue establish pathway position, single lab","pmids":["37953281"],"is_preprint":false},{"year":2023,"finding":"In fission yeast, the Stn1-Ten1 (ST) complex does not affect genome-wide replication but is specifically required for efficient replication of the subtelomeric STE3-2 fragile region. The ST complex binds STE3-2 and its replication function depends on association with shelterin proteins Pot1-Tpz1-Poz1 but is independent of Taz1. When ST function is compromised, a homologous recombination-based fork restart mechanism is required for STE3-2 stability.","method":"Genome-wide replication profiling, ChIP, genetic epistasis with HR factors and shelterin subunits","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genome-wide approach combined with ChIP and genetic epistasis, single lab","pmids":["37243596"],"is_preprint":false},{"year":2024,"finding":"Dysfunction of the telomeric Cdc13-Stn1-Ten1 complex simultaneously activates both the G2/M spindle checkpoints (Mad2-mediated and Bub2-mediated) and the G2/M DNA damage checkpoint (Mec1-mediated). SIZ1 (SUMO E3 ligase) and TOP2 were isolated as extragenic suppressors of CST temperature-sensitive mutants. Strong negative genetic interactions were identified between CST mutants and septins.","method":"Suppressor genetics, genetic epistasis with checkpoint mutants (mad2, bub2, mec1), temperature-sensitive mutant isolation","journal":"Cells","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — genetic epistasis placing CST at checkpoint activation, single lab, limited mechanistic follow-up","pmids":["39404369"],"is_preprint":false},{"year":2025,"finding":"The CTC1-STN1-TEN1 complex suppresses DNA end resection by EXO1 and the BLM-DNA2 helicase-nuclease complex via distinct mechanisms, controlling DSB repair pathway choice. BRCA1-BARD1 alleviates the CST-imposed EXO1 blockade but has little effect on BLM-DNA2 restriction. CST mutants impaired for DNA binding or BLM-EXO1 interaction exhibit a hyper-resection phenotype and render BRCA1-deficient cells resistant to PARP inhibitors.","method":"CST mutant analysis (DNA binding and BLM-EXO1 interaction deficient mutants), end resection assays, PARP inhibitor sensitivity assays, genetic epistasis with BRCA1-BARD1","journal":"Science (New York, N.Y.)","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple structure-guided mutants, resection assays, epistasis with BRCA1-BARD1, functional drug resistance readout — multiple orthogonal methods","pmids":["40403056"],"is_preprint":false},{"year":2025,"finding":"In a Ten1 homozygous knockout mouse model (CRISPR-Cas9 exon 3 deletion), loss of Ten1 causes telomere attrition, short lifespan, skin hyperpigmentation, aplastic anemia, and cerebellar hypoplasia. Molecular analyses revealed reduced proliferating cells, increased apoptosis, stem cell depletion, and activation of the p53/p21 signaling pathway, establishing that Ten1 deficiency in vivo causes telomere shortening and phenotypes resembling dyskeratosis congenita.","method":"CRISPR-Cas9 knockout mouse model, telomere length measurement, histology, flow cytometry (apoptosis, proliferation), immunostaining for p53/p21","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 2 / Strong — germline knockout with multiple organ/pathway readouts, first in vivo mammalian model for TEN1 loss-of-function","pmids":["40215293"],"is_preprint":false},{"year":2024,"finding":"Using cryo-EM structures of the human CST-Pol α/primase-DNA complex as guides, structural elements in yeast (C. glabrata) CST subunits Stn1 and Ten1 that contact Pri1 and Pri2 (primase subunits) were identified and mutated. These mutations abrogated CST stimulatory activity on Pol α/primase in vitro, demonstrating that physical contacts between Ten1/Stn1 and the primase complex are functionally required for C-strand synthesis.","method":"Cryo-EM structure-guided mutagenesis, in vitro Pol α/primase stimulation assays, in vivo telomere analysis in C. glabrata","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — cryo-EM structure-guided mutagenesis with in vitro reconstitution, but preprint not yet peer-reviewed","pmids":[],"is_preprint":true}],"current_model":"TEN1 is a component of the evolutionarily conserved CST (CTC1-STN1-TEN1) complex, an RPA-like heterotrimer in which TEN1 contains a single OB-fold that packs against the OB-fold of STN1 (structurally resembling the RPA2-RPA3 sub-complex); this interaction is required for TEN1's telomere localization and for the full telomere-protective function of CST. At telomeres, TEN1 is specifically required for C-strand fill-in synthesis (lagging-strand completion) downstream of G-overhang formation, acting by stabilizing CTC1-STN1 binding to ssDNA so that Pol α-primase can be engaged; TEN1 loss causes progressive telomere shortening without excessive G-overhang extension (unlike CTC1/STN1 loss). Beyond telomeres, CST including TEN1 promotes genome-wide replication restart after fork stalling, suppresses DNA end resection at double-strand breaks to control repair pathway choice, and in yeast modulates RNA Pol II transcription through physical interaction with the elongation factor Spt5. In vivo, Ten1 knockout mice phenocopy dyskeratosis congenita with telomere attrition, aplastic anemia, and p53/p21 activation."},"narrative":{"mechanistic_narrative":"TEN1 is the smallest subunit of the conserved CST (CTC1/Cdc13–STN1–TEN1) complex, an RPA-like single-stranded DNA-binding heterotrimer that protects chromosome ends and supports DNA replication [PMID:19854130, PMID:30026550]. Comprising a single OB fold, TEN1 packs against the OB domain of STN1 in an architecture closely resembling the RPA2–RPA3 subcomplex, and this interface is required for TEN1's telomere localization and for the telomere-protective function of CST [PMID:20008938, PMID:23826127]. At telomeres, TEN1 is specifically required for C-strand fill-in synthesis: depletion causes telomere fragility, telomere loss, and progressive shortening, while overhang elongation and telomerase regulation are spared, distinguishing TEN1 from CTC1/STN1 whose loss permits G-overhang overextension [PMID:24025336, PMID:30026550]. TEN1 stabilizes CTC1-STN1 binding to ssDNA so that Pol α-primase can be engaged for lagging-strand completion, and STN1/TEN1 directly contact and stimulate the primase complex to couple priming with C-strand synthesis [PMID:30026550, PMID:25503194]. Beyond telomeres, CST including TEN1 promotes genome-wide replication restart after fork stalling [PMID:24025336] and suppresses DNA end resection by EXO1 and BLM-DNA2 to govern double-strand break repair pathway choice, with CST resection-deficient mutants rendering BRCA1-deficient cells resistant to PARP inhibitors [PMID:40403056]. In yeast, Ten1 additionally modulates RNA Pol II transcription through physical association with the elongation factor Spt5 [PMID:31006804]. In vivo, Ten1 knockout mice display telomere attrition, aplastic anemia, cerebellar hypoplasia, and p53/p21 activation, phenocopying dyskeratosis congenita [PMID:40215293].","teleology":[{"year":2001,"claim":"Established that Ten1 is a bona fide telomere protection factor by showing it forms a trimeric complex with Stn1 and Cdc13 whose disruption causes ssDNA accumulation and checkpoint arrest, answering whether Ten1 has a dedicated end-capping role.","evidence":"Two-hybrid, genetic epistasis, and temperature-sensitive mutant analysis in budding yeast","pmids":["11230140"],"confidence":"High","gaps":["Did not define the structural basis of complex assembly","Mammalian relevance untested"]},{"year":2007,"claim":"Showed Stn1-Ten1 form a Pot1-independent complex at fission yeast telomeres, indicating CST is a conserved end-protection module separable from the shelterin Pot1 pathway.","evidence":"Co-IP, telomere localization assays, and structural prediction in S. pombe","pmids":["17715303"],"confidence":"High","gaps":["No structural confirmation of OB folds","Relationship to Pol α not addressed"]},{"year":2009,"claim":"Defined the mammalian CST complex as an RPA-like sequence-independent ssDNA-binding heterotrimer protecting telomeres independently of Pot1, and crystallography established that Stn1-Ten1 mimics the RPA2-RPA3 OB-fold interface required for Ten1 telomere localization.","evidence":"Co-IP, ssDNA binding, knockdown with FISH in human cells, and X-ray crystallography of Candida/S. pombe Stn1N-Ten1 plus mutagenesis","pmids":["19854130","20008938","19752213"],"confidence":"High","gaps":["Did not resolve TEN1-specific versus STN1-specific contributions","Mechanism of C-strand fill-in not yet defined"]},{"year":2010,"claim":"Mapped the direct Stn1-Ten1 interface via allele-specific suppression, confirming the RPA2-RPA3-analogous contact is genetically essential for complex integrity.","evidence":"Rpa2-OB chimera analysis, mutagenesis, and allele-specific suppression genetics in S. cerevisiae","pmids":["20157006"],"confidence":"High","gaps":["Interface defined genetically without human structural validation at the time"]},{"year":2011,"claim":"Demonstrated that CST acts specifically at the priming step on ssDNA templates rather than as a general replication factor, linking the complex to Pol α-primase function.","evidence":"Immunodepletion from Xenopus egg extracts with in vitro replication and rescue on pre-primed templates","pmids":["22086929"],"confidence":"High","gaps":["TEN1-specific contribution within xCST not isolated","Direct primase contacts not mapped"]},{"year":2013,"claim":"Resolved the human Stn1-Ten1 crystal structure and showed via dimerization-defective mutants that the telomeric function of human CST is TEN1-dependent, while assigning C-strand fill-in and replication restart roles to TEN1 in human cells.","evidence":"X-ray crystallography, ssDNA binding, mutant cell expression, telomere FISH, and BrdU replication restart assays in human cells","pmids":["23826127","24025336"],"confidence":"High","gaps":["Mechanism by which TEN1 stabilizes ssDNA binding not biochemically dissected","Pol α engagement step not directly observed"]},{"year":2013,"claim":"Established Cdk1-dependent phosphorylation of Stn1 as a cell-cycle timer that stabilizes CST at telomeres and balances telomerase versus CST recruitment.","evidence":"In vitro kinase assays, in vivo phosphosite mapping, and telomere ChIP in budding yeast","pmids":["24164896"],"confidence":"High","gaps":["TEN1 phosphoregulation not addressed","Conservation in mammals untested"]},{"year":2014,"claim":"Reconstituted CST stimulation of primase-Pol α activity in vitro, showing CST augments primase activity and primase-to-polymerase switching, providing the biochemical basis for C-strand synthesis.","evidence":"In vitro primase-polymerase assays with purified Candida glabrata complexes and domain mutagenesis","pmids":["25503194"],"confidence":"High","gaps":["Stn1 alone sufficed in assay, leaving TEN1's mechanistic contribution to stimulation unresolved"]},{"year":2014,"claim":"Dissected subunit-specific functions by CRISPR knockout, defining TEN1 as essential for C-strand synthesis (loss causes shortening) while overhang regulation maps to CTC1-STN1, and showing TEN1 stabilizes ssDNA binding to enable Pol α engagement.","evidence":"CRISPR knockout of individual subunits, G-overhang and telomere length analysis, and ssDNA binding assays in human colon cancer cells; plus Cdc13-independent CST function shown by NMD/DDR bypass genetics in yeast","pmids":["30026550","24835988"],"confidence":"High","gaps":["Structural mechanism of TEN1-mediated ssDNA stabilization not resolved","Cdc13-independence shown only in yeast"]},{"year":2018,"claim":"Placed Stn1-Ten1 recruitment downstream of shelterin via a SUMO-interacting motif in Stn1 that binds SUMOylated Tpz1, coupling CST to telomere replication and telomerase restriction in fission yeast.","evidence":"SIM mutagenesis, co-IP, ChIP, and telomere length analysis in S. pombe","pmids":["29774234"],"confidence":"High","gaps":["TEN1's direct role in the SUMO-dependent recruitment not separated from Stn1","Mammalian recruitment mechanism distinct"]},{"year":2017,"claim":"Extended CST function to alternative lengthening of telomeres, showing the complex supports ALT telomere maintenance and suppresses telomeric recombination.","evidence":"siRNA knockdown, immunofluorescence co-localization in APBs, telomere FISH, and C-circle assays in ALT cancer cells","pmids":["28366536"],"confidence":"Medium","gaps":["No TEN1-specific mechanistic dissection from STN1/CTC1","Single lab"]},{"year":2019,"claim":"Uncovered a non-telomeric role for Ten1/CST in transcription by showing physical association with the Spt5 elongation factor and regulation of RNA Pol II occupancy in yeast.","evidence":"Genetic interaction analysis, RNA Pol II and Spt5 ChIP, and co-IP in S. cerevisiae","pmids":["31006804"],"confidence":"Medium","gaps":["Mechanism of Spt5 regulation undefined","Conservation to mammals untested","Single lab"]},{"year":2019,"claim":"Refined shelterin-dependent recruitment by showing a Tpz1 SWSSS motif acts redundantly with SUMOylation to promote Stn1-Ten1 telomere binding that protects against telomere fusions.","evidence":"Mutagenesis of SWSSS motif and Lys242, co-IP, and telomere ChIP in fission yeast","pmids":["31396577"],"confidence":"Medium","gaps":["TEN1 contribution to the interaction not isolated"]},{"year":2020,"claim":"Quantified subunit-specific stringency by showing Stn1/Ten1 loss has a more severe survivor defect than Cdc13 loss in single-chromosome yeast, refining the hierarchy of CST capping functions.","evidence":"Gene deletion in single-linear-chromosome yeast with survivor frequency and Rad52/Yku epistasis","pmids":["32755541"],"confidence":"Medium","gaps":["Molecular basis of differential stringency unresolved","Specialized strain context"]},{"year":2023,"claim":"Established the pathway order at telomeres, placing Stn1-Ten1 (and Pol α-primase) recruitment downstream of Pot1-Tpz1 for lagging-strand synthesis, and assigned ST a specific role in subtelomeric fragile-region replication.","evidence":"Temperature-sensitive mutants, ChIP, overexpression rescue, and genome-wide replication profiling with shelterin/HR epistasis in fission yeast","pmids":["37953281","37243596"],"confidence":"Medium","gaps":["TEN1-specific role within ST not dissected","Mammalian fragile-region parallels untested"]},{"year":2024,"claim":"Linked CST checkpoint signaling to cell-cycle arrest by showing CST dysfunction activates both spindle and DNA damage G2/M checkpoints and interacts genetically with SUMO ligase, topoisomerase, and septins.","evidence":"Suppressor genetics and checkpoint mutant epistasis in budding yeast","pmids":["39404369"],"confidence":"Medium","gaps":["Mechanistic link between CST and spindle checkpoint unclear","TEN1-specific role not isolated"]},{"year":2025,"claim":"Defined a genome protection role beyond telomeres by showing CST suppresses DNA end resection via EXO1 and BLM-DNA2 to control repair pathway choice, with resection-deficient CST mutants conferring PARP inhibitor resistance in BRCA1-deficient cells.","evidence":"CST DNA-binding and BLM-EXO1 interaction mutants, end resection assays, PARP inhibitor sensitivity, and BRCA1-BARD1 epistasis","pmids":["40403056"],"confidence":"High","gaps":["TEN1-specific contribution to resection suppression not separated from CTC1/STN1","Structural basis of nuclease inhibition incomplete"]},{"year":2025,"claim":"Provided in vivo mammalian validation by showing Ten1 knockout mice develop telomere attrition, aplastic anemia, cerebellar hypoplasia, and p53/p21 activation, establishing TEN1 loss as a cause of dyskeratosis congenita-like disease.","evidence":"CRISPR-Cas9 knockout mouse with telomere length, histology, apoptosis/proliferation flow cytometry, and p53/p21 immunostaining","pmids":["40215293"],"confidence":"High","gaps":["Human TEN1 disease mutations not directly tested","Tissue-specific mechanisms of stem cell depletion incomplete"]},{"year":null,"claim":"How TEN1 specifically, as opposed to STN1/CTC1, stabilizes ssDNA binding and engages Pol α-primase at the structural level, and whether its non-telomeric transcription and resection roles operate through distinct interfaces, remain open.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No high-resolution mammalian CST-DNA-primase structure isolating TEN1 function in peer-reviewed corpus","TEN1-specific separation-of-function alleles for transcription and resection not defined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[2,6,7,14]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[3,7,14]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[10,14,21]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[2,8]},{"term_id":"GO:0000228","term_label":"nuclear chromosome","supporting_discovery_ids":[0,1,2,7]}],"pathway":[{"term_id":"R-HSA-69306","term_label":"DNA Replication","supporting_discovery_ids":[6,8,14,10]},{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[21]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[0,20]}],"complexes":["CST (CTC1/Cdc13-STN1-TEN1)"],"partners":["STN1","CTC1","CDC13","POT1","SPT5"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q86WV5","full_name":"CST complex subunit TEN1","aliases":["Protein telomeric pathways with STN1 homolog","Telomere length regulation protein TEN1 homolog"],"length_aa":123,"mass_kda":13.9,"function":"Component of the CST complex proposed to act as a specialized replication factor promoting DNA replication under conditions of replication stress or natural replication barriers such as the telomere duplex. The CST complex binds single-stranded DNA with high affinity in a sequence-independent manner, while isolated subunits bind DNA with low affinity by themselves. Initially the CST complex has been proposed to protect telomeres from DNA degradation (PubMed:19854130). However, the CST complex has been shown to be involved in several aspects of telomere replication. The CST complex inhibits telomerase and is involved in telomere length homeostasis; it is proposed to bind to newly telomerase-synthesized 3' overhangs and to terminate telomerase action implicating the association with the ACD:POT1 complex thus interfering with its telomerase stimulation activity. The CST complex is also proposed to be involved in fill-in synthesis of the telomeric C-strand probably implicating recruitment and activation of DNA polymerase alpha (PubMed:22763445). The CST complex facilitates recovery from many forms of exogenous DNA damage; seems to be involved in the re-initiation of DNA replication at repaired forks and/or dormant origins (PubMed:25483097)","subcellular_location":"Nucleus; Chromosome, telomere","url":"https://www.uniprot.org/uniprotkb/Q86WV5/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/TEN1","classification":"Common Essential","n_dependent_lines":725,"n_total_lines":1208,"dependency_fraction":0.6001655629139073},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/TEN1","total_profiled":1310},"omim":[{"mim_id":"620063","title":"DNA POLYMERASE ALPHA-2, ACCESSORY SUBUNIT; POLA2","url":"https://www.omim.org/entry/620063"},{"mim_id":"618030","title":"SHIELD COMPLEX, SUBUNIT 3; SHLD3","url":"https://www.omim.org/entry/618030"},{"mim_id":"618029","title":"SHIELD COMPLEX, SUBUNIT 2; SHLD2","url":"https://www.omim.org/entry/618029"},{"mim_id":"618028","title":"SHIELD COMPLEX, SUBUNIT 1; SHLD1","url":"https://www.omim.org/entry/618028"},{"mim_id":"613130","title":"TEN1, CST COMPLEX SUBUNIT; TEN1","url":"https://www.omim.org/entry/613130"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/TEN1"},"hgnc":{"alias_symbol":["FLJ39785"],"prev_symbol":["C17orf106"]},"alphafold":{"accession":"Q86WV5","domains":[{"cath_id":"2.40.50.140","chopping":"7-120","consensus_level":"high","plddt":95.1794,"start":7,"end":120}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q86WV5","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q86WV5-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q86WV5-F1-predicted_aligned_error_v6.png","plddt_mean":93.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TEN1","jax_strain_url":"https://www.jax.org/strain/search?query=TEN1"},"sequence":{"accession":"Q86WV5","fasta_url":"https://rest.uniprot.org/uniprotkb/Q86WV5.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q86WV5/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q86WV5"}},"corpus_meta":[{"pmid":"19854130","id":"PMC_19854130","title":"RPA-like mammalian 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associates with both Stn1 and Cdc13, forming a trimeric complex at telomeres. A binding defect between Stn1-13 and Ten1 was responsible for the long telomere phenotype of stn1-13 cells. Temperature-sensitive ten1 mutants accumulated single-stranded DNA at telomeric regions and arrested at G2/M via activation of the Rad9-dependent DNA damage checkpoint, establishing Ten1's role in telomere end protection and length regulation.\",\n      \"method\": \"Two-hybrid interaction, genetic epistasis, temperature-sensitive mutant analysis, checkpoint activation assays\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal two-hybrid, multiple mutant alleles with distinct phenotypes, checkpoint pathway placement, replicated across follow-up studies\",\n      \"pmids\": [\"11230140\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Fission yeast (S. pombe) Stn1 and Ten1 are orthologs that are essential for chromosome end protection. Stn1 and Ten1 associate with each other but not with Pot1, indicating they form a separate complex from Pot1 at fission yeast telomeres. Both proteins localize at telomeres in a manner correlating with the length of the ssDNA overhang, and structural profiling detects OB-fold domains in both.\",\n      \"method\": \"Co-immunoprecipitation, telomere localization assays, bioinformatics structural prediction, genetic analysis of null mutants\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal co-IP, direct localization experiments with functional consequence, independent from budding yeast work\",\n      \"pmids\": [\"17715303\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Mammalian TEN1, together with CTC1 and STN1, forms an RPA-like CST complex that binds single-stranded DNA with high affinity in a sequence-independent manner. The complex associates with a fraction of telomeres consistently throughout the cell cycle including in quiescent cells and Pot1-knockdown cells. STN1 knockdown increased single-stranded G-strand telomeric DNA abundance, establishing the CST complex role in protecting telomeres independently of the Pot1 pathway.\",\n      \"method\": \"Co-immunoprecipitation, ssDNA binding assays, knockdown (siRNA), fluorescence in situ hybridization\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (Co-IP, ssDNA binding, knockdown with FISH readout), foundational paper replicated across species\",\n      \"pmids\": [\"19854130\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Crystal structure of Candida tropicalis Stn1N complexed with Ten1 demonstrates an Rpa2N-Rpa3-like complex, where OB folds of the two components pack against each other through interactions between two C-terminal helices. The C-terminal domain of S. cerevisiae Stn1 comprises two WH motifs analogous to Rpa2. The fission yeast S. pombe Stn1N-Ten1 complex exhibits virtually identical architecture. Mutations disrupting the Stn1-Ten1 interaction induce telomere uncapping and abolish telomere localization of Ten1.\",\n      \"method\": \"X-ray crystallography, mutational analysis, telomere localization assays\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structures from multiple organisms combined with functional mutagenesis and localization assays\",\n      \"pmids\": [\"20008938\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Temperature-sensitive ten1 mutants in S. cerevisiae display elongated telomeres at permissive temperature and accumulate extensive telomeric single-stranded DNA at non-permissive conditions. Cdk1 activity is required to generate these single-stranded regions, and deleting EXO1 nuclease partially suppresses ten1-ts growth defects. Despite Cdc13 remaining bound at telomeres in ten1-ts cells, telomere end protection is lost, establishing that Cdc13 relies on Ten1 to execute its essential capping function. Ten1 also promotes de novo telomere addition.\",\n      \"method\": \"Temperature-sensitive mutant analysis, genetic epistasis (cdk1, exo1 deletion), chromatin immunoprecipitation, fluorescence microscopy of Rad52-YFP foci\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal genetic and cell biology approaches in a single focused study\",\n      \"pmids\": [\"19752213\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"A predicted alpha-helix in the N-terminal OB domain of S. cerevisiae Stn1 is required for interaction with Ten1, analogous to the Rpa2-Rpa3 interface in RPA. Mutations in a hydrophobic surface of the Stn1 alpha-helix eliminated Stn1-Ten1 association. Allele-specific suppression of stn1-L164D by ten1-D138Y restored the Stn1-Ten1 interaction, defining a direct Stn1-Ten1 interface.\",\n      \"method\": \"Rpa2-OB(Stn1) chimera analysis, site-directed mutagenesis, allele-specific suppression genetics, co-immunoprecipitation\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — allele-specific suppression plus mutagenesis plus chimeric protein analysis provides strong mechanistic evidence for the interface\",\n      \"pmids\": [\"20157006\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Xenopus laevis CST (xCST), including xTen1, forms an ssDNA-binding complex with moderate preference for G-rich sequences. Immunodepletion of xStn1 from egg extracts did not affect chromosomal DNA replication from sperm nuclei but specifically compromised DNA synthesis on ssDNA templates; this defect was rescued by pre-primed ssDNA templates, establishing that xCST is involved in the priming step on ssDNA template rather than being a general replication factor.\",\n      \"method\": \"Immunodepletion from Xenopus egg extracts, in vitro DNA replication assays on ssDNA templates, ssDNA binding assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstituted in vitro priming assay with immunodepletion rescue, single lab but multiple orthogonal approaches\",\n      \"pmids\": [\"22086929\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Crystal structure of the human Stn1-Ten1 (hStn1-Ten1) complex reveals that hStn1 consists of an OB domain and tandem C-terminal wHTH motifs, while hTen1 consists of a single OB fold. Contacts between OB domains mediate complex formation strikingly similar to RPA. The hStn1-Ten1 complex exhibits non-specific ssDNA binding activity primarily dependent on hStn1. Cells expressing hStn1 mutants defective for dimerization with hTen1 display elongated telomeres and telomere uncapping defects, demonstrating that the telomeric function of hCST is hTen1-dependent.\",\n      \"method\": \"X-ray crystallography, ssDNA binding assays, cell-based mutant expression, telomere length analysis, telomere FISH\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure of human complex combined with structure-guided mutagenesis and functional cell-based validation\",\n      \"pmids\": [\"23826127\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Human TEN1 depletion causes increased multitelomere FISH signals (indicative of telomere duplex replication defects) and telomere loss without increased deprotection, recombination, or T-circle release. TEN1 depletion delays G-overhang shortening in late S/G2 but does not affect overhang elongation in mid-S phase, indicating a role in C-strand fill-in but not telomerase regulation. TEN1 depletion also reduces genome-wide replication restart after fork stalling, similar to STN1 depletion.\",\n      \"method\": \"siRNA knockdown, telomere FISH, BrdU incorporation assay for replication restart, G-overhang analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal assays (FISH, replication restart, overhang analysis) in human cells, focused on TEN1 specifically\",\n      \"pmids\": [\"24025336\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"In budding yeast, Cdk1 phosphorylates Stn1 at Thr223 and Ser250 both in vitro and in vivo. These phosphorylation events are essential for the stability of CST (Cdc13-Stn1-Ten1) complexes at telomeres. By controlling the timing of Cdc13 and Stn1 phosphorylations during the cell cycle, Cdk1 regulates the temporal recruitment of telomerase complexes versus CST complexes to telomeres to facilitate telomere maintenance.\",\n      \"method\": \"In vitro kinase assays, in vivo phosphorylation mapping, telomere chromatin immunoprecipitation, cell cycle synchronization\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro kinase assay combined with in vivo phosphorylation mapping and ChIP, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"24164896\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"The CDC13-STN1-TEN1 (CST) complex from Candida glabrata stimulates primase-Pol α (PP) activity by augmenting primase activity and primase-to-polymerase switching, simultaneously shortening the RNA primer and lengthening the DNA product. CST does not enhance isolated DNA polymerase activity alone. The Stn1 subunit alone is sufficient for PP stimulation. Both the N-terminal OB fold and C-terminal winged-helix domains of Stn1 bind the Pol12 subunit of PP and stimulate PP activity.\",\n      \"method\": \"In vitro primase-polymerase activity assays with purified complexes, domain deletion/mutagenesis, binding assays\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstituted in vitro with purified components, domain-level mutagenesis defining mechanism, specific for Stn1 within the CST complex\",\n      \"pmids\": [\"25503194\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"In S. cerevisiae, the requirement for Cdc13 (but not for Stn1 or Ten1) can be bypassed when both the DNA damage response and nonsense-mediated mRNA decay (NMD) pathways are inactivated. Disabling NMD alters stoichiometry of CST components at telomeres and permits Stn1 to bind telomeres in the absence of Cdc13, supporting a model that Stn1 and Ten1 can function in a Cdc13-independent manner.\",\n      \"method\": \"Genetic epistasis, telomere chromatin immunoprecipitation, double mutant bypass analysis\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis combined with ChIP showing Stn1 telomere binding in cdc13 mutant, single lab\",\n      \"pmids\": [\"24835988\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"The human CST complex (CTC1-STN1-TEN1) forms a functional complex that localizes in ALT-associated PML bodies (APBs) in ALT cancer cells. CST suppression in ALT cells induces telomere fragility, elevates telomeric DNA recombination, diminishes C-circles and t-circles abundance, and causes multinucleation, establishing a role for CST including TEN1 in ALT telomere maintenance.\",\n      \"method\": \"siRNA knockdown, immunofluorescence co-localization, telomere FISH, C-circle assay, flow cytometry\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple readouts in ALT cells, single lab, no specific TEN1 mechanistic dissection from STN1/CTC1\",\n      \"pmids\": [\"28366536\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"In fission yeast, the Stn1-Ten1 complex restricts telomerase action via a SUMO-interacting motif (SIM) in the C-terminal part of Stn1. The SIM mediates interaction with SUMOylated Tpz1 (TPP1 ortholog). Point mutations in the SIM (Stn1-226) lead to telomere elongation, impair Stn1-Ten1 recruitment to telomeres, and enhance telomerase binding. Stn1-Ten1 also promotes DNA synthesis at telomeres to limit ssDNA accumulation and functions in replication of telomeric and subtelomeric regions in a Taz1-independent manner.\",\n      \"method\": \"Mutagenesis (SIM mutations), co-immunoprecipitation, ChIP, telomere length analysis, genetic analysis of replication mutants\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — structure-guided mutagenesis, reciprocal Co-IP, ChIP with functional consequences, multiple orthogonal methods in one study\",\n      \"pmids\": [\"29774234\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"In human colon cancer cells, CTC1-STN1 (without TEN1) is sufficient to limit telomerase action and prevent G-overhang overextension; CTC1-/- cells exhibit overhang elongation whereas TEN1-/- cells do not. However, TEN1 is essential for C-strand synthesis, and TEN1-/- cells exhibit progressive telomere shortening. DNA binding analysis indicates that CTC1-STN1 retains ssDNA affinity but TEN1 stabilizes this binding, enabling proper engagement of Pol α for C-strand synthesis.\",\n      \"method\": \"CRISPR knockout of individual subunits, G-overhang analysis, telomere length measurements, ssDNA binding assays\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — CRISPR KO of each subunit separately with multiple orthogonal readouts, dissecting subunit-specific functions\",\n      \"pmids\": [\"30026550\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"In S. cerevisiae, Ten1 (as part of the CST complex) regulates RNA polymerase II transcription. Genetic interactions between TEN1 and transcription regulators were found, and molecular assays showed Ten1 regulates the occupancies of RNA Pol II and the Spt5 elongation factor within transcribed genes. Ten1, Cdc13, and Stn1 all physically associate with Spt5, identifying Spt5 as the target of CST in transcription regulation. CST also physically associates with Hmo1.\",\n      \"method\": \"Genetic interaction analysis, ChIP (RNA Pol II and Spt5 occupancy), co-immunoprecipitation with Spt5\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and Co-IP in a single lab, novel function for CST in transcription with molecular mechanism partially defined\",\n      \"pmids\": [\"31006804\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"In fission yeast, a conserved SWSSS motif in Tpz1 (adjacent to Lys242 SUMOylation site) works redundantly with Lys242 SUMOylation to promote Stn1-Ten1 binding at telomere and sub-telomere regions. This binding protects against SSA-dependent telomere fusions and prevents telomerase accumulation at telomeres.\",\n      \"method\": \"Mutagenesis of SWSSS motif and Lys242, co-immunoprecipitation, telomere ChIP, telomere southern blot\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — structure-guided mutagenesis and ChIP showing Stn1-Ten1 recruitment depends on Tpz1, single lab\",\n      \"pmids\": [\"31396577\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"In single-linear-chromosome yeast (SY14), deletion of TEN1 (or STN1) leads to a ~29-fold lower frequency of survivors compared to CDC13 deletion, demonstrating that Ten1 and Stn1 have a more stringent requirement than Cdc13 in preventing telomere fusion. CDC13 deletion leads to Rad52-dependent intrachromosome end-to-end fusions, while Stn1/Ten1 loss does not produce fusion at the same frequency.\",\n      \"method\": \"Gene deletion in single-linear-chromosome yeast, survivor frequency analysis, genetic epistasis with Rad52 and Yku\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — quantitative genetic analysis in specialized yeast strain, single lab, dissects subunit-specific roles\",\n      \"pmids\": [\"32755541\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"In fission yeast, Pot1 promotes telomere DNA replication by recruiting the Stn1-Ten1 complex (and Pol α-primase) to telomeres via Tpz1. In pot1-1 temperature-sensitive mutants, Stn1 recruitment to telomeres is reduced and ssDNA accumulates; overexpression of Stn1 rescues telomere loss and cell viability, placing Ten1/Stn1 downstream of Pot1-Tpz1 in the lagging-strand synthesis pathway.\",\n      \"method\": \"Temperature-sensitive mutant analysis, ChIP, overexpression rescue, telomere Southern blot\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and genetic rescue establish pathway position, single lab\",\n      \"pmids\": [\"37953281\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"In fission yeast, the Stn1-Ten1 (ST) complex does not affect genome-wide replication but is specifically required for efficient replication of the subtelomeric STE3-2 fragile region. The ST complex binds STE3-2 and its replication function depends on association with shelterin proteins Pot1-Tpz1-Poz1 but is independent of Taz1. When ST function is compromised, a homologous recombination-based fork restart mechanism is required for STE3-2 stability.\",\n      \"method\": \"Genome-wide replication profiling, ChIP, genetic epistasis with HR factors and shelterin subunits\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genome-wide approach combined with ChIP and genetic epistasis, single lab\",\n      \"pmids\": [\"37243596\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Dysfunction of the telomeric Cdc13-Stn1-Ten1 complex simultaneously activates both the G2/M spindle checkpoints (Mad2-mediated and Bub2-mediated) and the G2/M DNA damage checkpoint (Mec1-mediated). SIZ1 (SUMO E3 ligase) and TOP2 were isolated as extragenic suppressors of CST temperature-sensitive mutants. Strong negative genetic interactions were identified between CST mutants and septins.\",\n      \"method\": \"Suppressor genetics, genetic epistasis with checkpoint mutants (mad2, bub2, mec1), temperature-sensitive mutant isolation\",\n      \"journal\": \"Cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — genetic epistasis placing CST at checkpoint activation, single lab, limited mechanistic follow-up\",\n      \"pmids\": [\"39404369\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"The CTC1-STN1-TEN1 complex suppresses DNA end resection by EXO1 and the BLM-DNA2 helicase-nuclease complex via distinct mechanisms, controlling DSB repair pathway choice. BRCA1-BARD1 alleviates the CST-imposed EXO1 blockade but has little effect on BLM-DNA2 restriction. CST mutants impaired for DNA binding or BLM-EXO1 interaction exhibit a hyper-resection phenotype and render BRCA1-deficient cells resistant to PARP inhibitors.\",\n      \"method\": \"CST mutant analysis (DNA binding and BLM-EXO1 interaction deficient mutants), end resection assays, PARP inhibitor sensitivity assays, genetic epistasis with BRCA1-BARD1\",\n      \"journal\": \"Science (New York, N.Y.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple structure-guided mutants, resection assays, epistasis with BRCA1-BARD1, functional drug resistance readout — multiple orthogonal methods\",\n      \"pmids\": [\"40403056\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In a Ten1 homozygous knockout mouse model (CRISPR-Cas9 exon 3 deletion), loss of Ten1 causes telomere attrition, short lifespan, skin hyperpigmentation, aplastic anemia, and cerebellar hypoplasia. Molecular analyses revealed reduced proliferating cells, increased apoptosis, stem cell depletion, and activation of the p53/p21 signaling pathway, establishing that Ten1 deficiency in vivo causes telomere shortening and phenotypes resembling dyskeratosis congenita.\",\n      \"method\": \"CRISPR-Cas9 knockout mouse model, telomere length measurement, histology, flow cytometry (apoptosis, proliferation), immunostaining for p53/p21\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — germline knockout with multiple organ/pathway readouts, first in vivo mammalian model for TEN1 loss-of-function\",\n      \"pmids\": [\"40215293\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Using cryo-EM structures of the human CST-Pol α/primase-DNA complex as guides, structural elements in yeast (C. glabrata) CST subunits Stn1 and Ten1 that contact Pri1 and Pri2 (primase subunits) were identified and mutated. These mutations abrogated CST stimulatory activity on Pol α/primase in vitro, demonstrating that physical contacts between Ten1/Stn1 and the primase complex are functionally required for C-strand synthesis.\",\n      \"method\": \"Cryo-EM structure-guided mutagenesis, in vitro Pol α/primase stimulation assays, in vivo telomere analysis in C. glabrata\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cryo-EM structure-guided mutagenesis with in vitro reconstitution, but preprint not yet peer-reviewed\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"TEN1 is a component of the evolutionarily conserved CST (CTC1-STN1-TEN1) complex, an RPA-like heterotrimer in which TEN1 contains a single OB-fold that packs against the OB-fold of STN1 (structurally resembling the RPA2-RPA3 sub-complex); this interaction is required for TEN1's telomere localization and for the full telomere-protective function of CST. At telomeres, TEN1 is specifically required for C-strand fill-in synthesis (lagging-strand completion) downstream of G-overhang formation, acting by stabilizing CTC1-STN1 binding to ssDNA so that Pol α-primase can be engaged; TEN1 loss causes progressive telomere shortening without excessive G-overhang extension (unlike CTC1/STN1 loss). Beyond telomeres, CST including TEN1 promotes genome-wide replication restart after fork stalling, suppresses DNA end resection at double-strand breaks to control repair pathway choice, and in yeast modulates RNA Pol II transcription through physical interaction with the elongation factor Spt5. In vivo, Ten1 knockout mice phenocopy dyskeratosis congenita with telomere attrition, aplastic anemia, and p53/p21 activation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TEN1 is the smallest subunit of the conserved CST (CTC1/Cdc13–STN1–TEN1) complex, an RPA-like single-stranded DNA-binding heterotrimer that protects chromosome ends and supports DNA replication [#2, #14]. Comprising a single OB fold, TEN1 packs against the OB domain of STN1 in an architecture closely resembling the RPA2–RPA3 subcomplex, and this interface is required for TEN1's telomere localization and for the telomere-protective function of CST [#3, #7]. At telomeres, TEN1 is specifically required for C-strand fill-in synthesis: depletion causes telomere fragility, telomere loss, and progressive shortening, while overhang elongation and telomerase regulation are spared, distinguishing TEN1 from CTC1/STN1 whose loss permits G-overhang overextension [#8, #14]. TEN1 stabilizes CTC1-STN1 binding to ssDNA so that Pol α-primase can be engaged for lagging-strand completion, and STN1/TEN1 directly contact and stimulate the primase complex to couple priming with C-strand synthesis [#14, #10]. Beyond telomeres, CST including TEN1 promotes genome-wide replication restart after fork stalling [#8] and suppresses DNA end resection by EXO1 and BLM-DNA2 to govern double-strand break repair pathway choice, with CST resection-deficient mutants rendering BRCA1-deficient cells resistant to PARP inhibitors [#21]. In yeast, Ten1 additionally modulates RNA Pol II transcription through physical association with the elongation factor Spt5 [#15]. In vivo, Ten1 knockout mice display telomere attrition, aplastic anemia, cerebellar hypoplasia, and p53/p21 activation, phenocopying dyskeratosis congenita [#22].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Established that Ten1 is a bona fide telomere protection factor by showing it forms a trimeric complex with Stn1 and Cdc13 whose disruption causes ssDNA accumulation and checkpoint arrest, answering whether Ten1 has a dedicated end-capping role.\",\n      \"evidence\": \"Two-hybrid, genetic epistasis, and temperature-sensitive mutant analysis in budding yeast\",\n      \"pmids\": [\"11230140\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define the structural basis of complex assembly\", \"Mammalian relevance untested\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Showed Stn1-Ten1 form a Pot1-independent complex at fission yeast telomeres, indicating CST is a conserved end-protection module separable from the shelterin Pot1 pathway.\",\n      \"evidence\": \"Co-IP, telomere localization assays, and structural prediction in S. pombe\",\n      \"pmids\": [\"17715303\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structural confirmation of OB folds\", \"Relationship to Pol α not addressed\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Defined the mammalian CST complex as an RPA-like sequence-independent ssDNA-binding heterotrimer protecting telomeres independently of Pot1, and crystallography established that Stn1-Ten1 mimics the RPA2-RPA3 OB-fold interface required for Ten1 telomere localization.\",\n      \"evidence\": \"Co-IP, ssDNA binding, knockdown with FISH in human cells, and X-ray crystallography of Candida/S. pombe Stn1N-Ten1 plus mutagenesis\",\n      \"pmids\": [\"19854130\", \"20008938\", \"19752213\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve TEN1-specific versus STN1-specific contributions\", \"Mechanism of C-strand fill-in not yet defined\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Mapped the direct Stn1-Ten1 interface via allele-specific suppression, confirming the RPA2-RPA3-analogous contact is genetically essential for complex integrity.\",\n      \"evidence\": \"Rpa2-OB chimera analysis, mutagenesis, and allele-specific suppression genetics in S. cerevisiae\",\n      \"pmids\": [\"20157006\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Interface defined genetically without human structural validation at the time\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Demonstrated that CST acts specifically at the priming step on ssDNA templates rather than as a general replication factor, linking the complex to Pol α-primase function.\",\n      \"evidence\": \"Immunodepletion from Xenopus egg extracts with in vitro replication and rescue on pre-primed templates\",\n      \"pmids\": [\"22086929\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"TEN1-specific contribution within xCST not isolated\", \"Direct primase contacts not mapped\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Resolved the human Stn1-Ten1 crystal structure and showed via dimerization-defective mutants that the telomeric function of human CST is TEN1-dependent, while assigning C-strand fill-in and replication restart roles to TEN1 in human cells.\",\n      \"evidence\": \"X-ray crystallography, ssDNA binding, mutant cell expression, telomere FISH, and BrdU replication restart assays in human cells\",\n      \"pmids\": [\"23826127\", \"24025336\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which TEN1 stabilizes ssDNA binding not biochemically dissected\", \"Pol α engagement step not directly observed\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Established Cdk1-dependent phosphorylation of Stn1 as a cell-cycle timer that stabilizes CST at telomeres and balances telomerase versus CST recruitment.\",\n      \"evidence\": \"In vitro kinase assays, in vivo phosphosite mapping, and telomere ChIP in budding yeast\",\n      \"pmids\": [\"24164896\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"TEN1 phosphoregulation not addressed\", \"Conservation in mammals untested\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Reconstituted CST stimulation of primase-Pol α activity in vitro, showing CST augments primase activity and primase-to-polymerase switching, providing the biochemical basis for C-strand synthesis.\",\n      \"evidence\": \"In vitro primase-polymerase assays with purified Candida glabrata complexes and domain mutagenesis\",\n      \"pmids\": [\"25503194\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stn1 alone sufficed in assay, leaving TEN1's mechanistic contribution to stimulation unresolved\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Dissected subunit-specific functions by CRISPR knockout, defining TEN1 as essential for C-strand synthesis (loss causes shortening) while overhang regulation maps to CTC1-STN1, and showing TEN1 stabilizes ssDNA binding to enable Pol α engagement.\",\n      \"evidence\": \"CRISPR knockout of individual subunits, G-overhang and telomere length analysis, and ssDNA binding assays in human colon cancer cells; plus Cdc13-independent CST function shown by NMD/DDR bypass genetics in yeast\",\n      \"pmids\": [\"30026550\", \"24835988\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural mechanism of TEN1-mediated ssDNA stabilization not resolved\", \"Cdc13-independence shown only in yeast\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Placed Stn1-Ten1 recruitment downstream of shelterin via a SUMO-interacting motif in Stn1 that binds SUMOylated Tpz1, coupling CST to telomere replication and telomerase restriction in fission yeast.\",\n      \"evidence\": \"SIM mutagenesis, co-IP, ChIP, and telomere length analysis in S. pombe\",\n      \"pmids\": [\"29774234\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"TEN1's direct role in the SUMO-dependent recruitment not separated from Stn1\", \"Mammalian recruitment mechanism distinct\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Extended CST function to alternative lengthening of telomeres, showing the complex supports ALT telomere maintenance and suppresses telomeric recombination.\",\n      \"evidence\": \"siRNA knockdown, immunofluorescence co-localization in APBs, telomere FISH, and C-circle assays in ALT cancer cells\",\n      \"pmids\": [\"28366536\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No TEN1-specific mechanistic dissection from STN1/CTC1\", \"Single lab\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Uncovered a non-telomeric role for Ten1/CST in transcription by showing physical association with the Spt5 elongation factor and regulation of RNA Pol II occupancy in yeast.\",\n      \"evidence\": \"Genetic interaction analysis, RNA Pol II and Spt5 ChIP, and co-IP in S. cerevisiae\",\n      \"pmids\": [\"31006804\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of Spt5 regulation undefined\", \"Conservation to mammals untested\", \"Single lab\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Refined shelterin-dependent recruitment by showing a Tpz1 SWSSS motif acts redundantly with SUMOylation to promote Stn1-Ten1 telomere binding that protects against telomere fusions.\",\n      \"evidence\": \"Mutagenesis of SWSSS motif and Lys242, co-IP, and telomere ChIP in fission yeast\",\n      \"pmids\": [\"31396577\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"TEN1 contribution to the interaction not isolated\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Quantified subunit-specific stringency by showing Stn1/Ten1 loss has a more severe survivor defect than Cdc13 loss in single-chromosome yeast, refining the hierarchy of CST capping functions.\",\n      \"evidence\": \"Gene deletion in single-linear-chromosome yeast with survivor frequency and Rad52/Yku epistasis\",\n      \"pmids\": [\"32755541\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular basis of differential stringency unresolved\", \"Specialized strain context\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Established the pathway order at telomeres, placing Stn1-Ten1 (and Pol α-primase) recruitment downstream of Pot1-Tpz1 for lagging-strand synthesis, and assigned ST a specific role in subtelomeric fragile-region replication.\",\n      \"evidence\": \"Temperature-sensitive mutants, ChIP, overexpression rescue, and genome-wide replication profiling with shelterin/HR epistasis in fission yeast\",\n      \"pmids\": [\"37953281\", \"37243596\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"TEN1-specific role within ST not dissected\", \"Mammalian fragile-region parallels untested\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Linked CST checkpoint signaling to cell-cycle arrest by showing CST dysfunction activates both spindle and DNA damage G2/M checkpoints and interacts genetically with SUMO ligase, topoisomerase, and septins.\",\n      \"evidence\": \"Suppressor genetics and checkpoint mutant epistasis in budding yeast\",\n      \"pmids\": [\"39404369\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanistic link between CST and spindle checkpoint unclear\", \"TEN1-specific role not isolated\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Defined a genome protection role beyond telomeres by showing CST suppresses DNA end resection via EXO1 and BLM-DNA2 to control repair pathway choice, with resection-deficient CST mutants conferring PARP inhibitor resistance in BRCA1-deficient cells.\",\n      \"evidence\": \"CST DNA-binding and BLM-EXO1 interaction mutants, end resection assays, PARP inhibitor sensitivity, and BRCA1-BARD1 epistasis\",\n      \"pmids\": [\"40403056\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"TEN1-specific contribution to resection suppression not separated from CTC1/STN1\", \"Structural basis of nuclease inhibition incomplete\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Provided in vivo mammalian validation by showing Ten1 knockout mice develop telomere attrition, aplastic anemia, cerebellar hypoplasia, and p53/p21 activation, establishing TEN1 loss as a cause of dyskeratosis congenita-like disease.\",\n      \"evidence\": \"CRISPR-Cas9 knockout mouse with telomere length, histology, apoptosis/proliferation flow cytometry, and p53/p21 immunostaining\",\n      \"pmids\": [\"40215293\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Human TEN1 disease mutations not directly tested\", \"Tissue-specific mechanisms of stem cell depletion incomplete\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How TEN1 specifically, as opposed to STN1/CTC1, stabilizes ssDNA binding and engages Pol α-primase at the structural level, and whether its non-telomeric transcription and resection roles operate through distinct interfaces, remain open.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No high-resolution mammalian CST-DNA-primase structure isolating TEN1 function in peer-reviewed corpus\", \"TEN1-specific separation-of-function alleles for transcription and resection not defined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [2, 6, 7, 14]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [3, 7, 14]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [10, 14, 21, 24]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [2, 8]},\n      {\"term_id\": \"GO:0000228\", \"supporting_discovery_ids\": [0, 1, 2, 7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-69306\", \"supporting_discovery_ids\": [6, 8, 14, 10]},\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [21]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [0, 20]}\n    ],\n    \"complexes\": [\"CST (CTC1/Cdc13-STN1-TEN1)\"],\n    \"partners\": [\"STN1\", \"CTC1\", \"CDC13\", \"POT1\", \"SPT5\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}