{"gene":"RFC3","run_date":"2026-06-10T06:43:36","timeline":{"discoveries":[{"year":1994,"finding":"The yeast RFC3 gene encodes the 40-kDa subunit of Replication Factor C (RF-C), an essential multi-polypeptide complex required for processive DNA replication by DNA polymerases delta and epsilon. Purified Rfc3p displays ATPase activity that is markedly stimulated by single-stranded DNA but not by double-stranded DNA or RNA.","method":"Molecular cloning, gene disruption (essential gene), overexpression in E. coli, purification to homogeneity, in vitro ATPase assay","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro biochemical reconstitution with purified protein, ATPase assay with defined substrates, genetic essentiality demonstrated","pmids":["8302859"],"is_preprint":false},{"year":2001,"finding":"The conserved Walker A lysine (K59) in the ATP-binding domain of yeast Rfc3 is essential for ATPase activity, DNA binding, and clamp (PCNA) loading. A rfc3-K59E mutation severely impairs ATP hydrolysis, DNA binding, and clamp loading activity. A conservative rfc3-K59R mutation shows only mild clamp loading defects that are fully suppressed at high ATP concentrations, indicating Rfc3's ATP-binding domain is critical for DNA recognition and PCNA loading.","method":"Site-directed mutagenesis of Walker A motif, overexpression in E. coli, in vitro ATPase assay, clamp loading assay, DNA binding assay, PCNA interaction assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — active-site mutagenesis combined with multiple in vitro biochemical assays (ATPase, clamp loading, DNA binding, PCNA interaction) in reconstituted system","pmids":["11432854"],"is_preprint":false},{"year":2000,"finding":"The S. pombe rfc3+ gene encodes an ortholog of S. cerevisiae Rfc3 and human hRFC36. It is essential for DNA replication; rfc3Δ cells are defective for DNA replication. Heterologous expression of either S. cerevisiae Rfc3 or human hRFC36 rescues the loss of S. pombe rfc3+ function, demonstrating functional conservation across species.","method":"Gene cloning, gene disruption (essential gene), heterologous complementation with S. cerevisiae Rfc3 and human hRFC36","journal":"Current genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic essentiality and cross-species complementation establish conserved role in DNA replication","pmids":["10794172"],"is_preprint":false},{"year":2012,"finding":"RFC3 knockdown inhibits proliferation and anchorage-independent growth of cancer cells with increased RFC3 copy number, establishing RFC3 as functionally required for proliferation in a copy-number-dependent manner (candidate oncogene in esophageal adenocarcinoma).","method":"RFC3 knockdown (siRNA/shRNA), cell proliferation assay, anchorage-independent growth assay, comparative genomic hybridization, gene expression integration","journal":"Clinical cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KD with defined cellular phenotype (proliferation, anchorage-independent growth), copy-number dependency established, single lab","pmids":["22328562"],"is_preprint":false},{"year":2015,"finding":"shRNA-mediated knockdown of RFC3 in hepatocellular carcinoma cells suppresses cell viability and proliferation, and arrests the cell cycle in S phase, partly by regulating expression of cell cycle-related proteins p21, p53, p57, and cyclin A.","method":"Lentivirus-mediated shRNA knockdown, MTS assay, cell growth assay, flow cytometry (cell cycle), western blot (p21, p53, p57, cyclin A)","journal":"International journal of molecular medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KD with defined cellular phenotype and molecular readout (cell cycle proteins), two orthogonal methods, single lab","pmids":["26397132"],"is_preprint":false},{"year":2015,"finding":"shRNA-mediated knockdown of RFC3 in ovarian cancer OVCAR-3 cells suppresses cell viability and proliferation, arrests the cell cycle in S phase, and induces apoptosis.","method":"Lentivirus-mediated shRNA knockdown, MTS assay, cell growth assay, flow cytometry (cell cycle, apoptosis)","journal":"International journal of clinical and experimental pathology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KD with defined cellular phenotype (S-phase arrest, apoptosis), two orthogonal methods, single lab","pmids":["26464638"],"is_preprint":false},{"year":2017,"finding":"RFC3 (and the RFC complex broadly) acts as a host restriction factor limiting orthopoxvirus SPI-1 deletion mutant replication in human cells. siRNA depletion of RFC3 (and RFC1, RFC2, RFC4, RFC5) significantly enhances replication and spread of the SPI-1 mutant virus, identifying RFC complex as an antiviral restriction factor. IRF2 regulates basal expression of FAM111A, which in turn enhances the host restriction effect of RFC3 on poxvirus replication.","method":"Genome-wide siRNA screen, secondary siRNA validation, virus replication/spread assays, microarray, quantitative RT-PCR, immunoblotting","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genome-wide siRNA screen confirmed by secondary assays, multiple RFC subunit siRNAs tested, single lab but multiple orthogonal methods","pmids":["28320935"],"is_preprint":false},{"year":2021,"finding":"IRF2 inhibits Zika virus (ZIKV) replication by activating FAM111A expression, which in turn enhances the host restriction effect of RFC3. siRNA knockdown of RFC3 in ZIKV-infected cells reduces restriction of viral replication, placing RFC3 downstream of the IRF2–FAM111A axis in antiviral defense.","method":"siRNA knockdown of IRF2, FAM111A, and RFC3; overexpression of IRF2; RT-qPCR; western blot; viral replication assays in A549, 2FTGH, and U5A cells","journal":"Virology journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — epistasis established by siRNA knockdown of pathway components with viral replication readout, single lab, multiple cell lines","pmids":["34930359"],"is_preprint":false},{"year":2024,"finding":"RFC3 physically interacts with KIF14 (kinesin family member 14) in colorectal cancer cells, as demonstrated by co-immunoprecipitation. RFC3 depletion reduces KIF14 expression, and KIF14 overexpression reverses the anti-proliferative, anti-migratory, anti-invasive, and anti-angiogenic effects of RFC3 knockdown, placing KIF14 downstream of RFC3 in CRC malignant progression.","method":"Co-immunoprecipitation, siRNA knockdown, KIF14 overexpression rescue experiment, CCK-8 assay, EdU assay, flow cytometry, wound healing assay, Transwell assay, tube formation assay, western blot","journal":"Experimental and therapeutic medicine","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — single Co-IP for interaction, but rescue experiment with KIF14 overexpression provides epistasis support; single lab, multiple orthogonal cellular assays","pmids":["38590579"],"is_preprint":false},{"year":2024,"finding":"The YAP1/TEAD signaling axis transcriptionally activates RFC3 expression by binding to the RFC3 promoter. YAP1/TEAD-driven RFC3 upregulation promotes gastric cancer cell proliferation, migration, invasion, and in vivo tumor growth and metastasis.","method":"Dual luciferase reporter assay (YAP1/TEAD binding to RFC3 promoter), lentivirus-mediated shRNA knockdown of RFC3, in vitro cell assays, in vivo xenograft/metastasis assays","journal":"International journal of clinical oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — dual luciferase reporter assay establishes transcriptional regulation, supported by KD cellular phenotypes and in vivo data; single lab","pmids":["38383698"],"is_preprint":false},{"year":2025,"finding":"RFC3 knockdown in colorectal cancer cells enhances sensitivity to oxaliplatin by inducing ferroptosis. The mechanism involves disruption of the Wnt/β-catenin/GPX4 signaling axis, as assessed by immunoblot analysis of pathway components.","method":"siRNA knockdown, cell viability assay, clonogenic survival assay, flow cytometry, immunoblot (Wnt/β-catenin/GPX4 axis proteins), ferroptosis readouts","journal":"Fundamental & clinical pharmacology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single method for pathway (immunoblot only), mechanism inferred from protein expression changes without direct pathway reconstitution","pmids":["39749364"],"is_preprint":false}],"current_model":"RFC3 encodes a subunit of the heteropentameric Replication Factor C (RFC) clamp loader complex; its conserved Walker A ATP-binding domain (K59 in yeast) is essential for ATPase activity, DNA recognition, and PCNA clamp loading onto DNA to enable processive replication by DNA polymerases delta and epsilon. Beyond its core replication function, RFC3 participates in cell cycle progression (S-phase regulation involving p21, p53, p57, and cyclin A), acts as a host restriction factor for poxviruses and ZIKV downstream of an IRF2–FAM111A axis, physically interacts with KIF14 to drive cancer cell proliferation and invasion, and is transcriptionally activated by the YAP1/TEAD signaling pathway in gastric cancer."},"narrative":{"mechanistic_narrative":"RFC3 encodes a subunit of the heteropentameric Replication Factor C (RF-C) clamp loader, an essential complex required for processive DNA replication by DNA polymerases delta and epsilon [PMID:8302859]. The purified protein displays ATPase activity strongly stimulated by single-stranded DNA, and its conserved Walker A lysine (K59) is essential for ATP hydrolysis, DNA binding, and loading of the PCNA clamp onto DNA [PMID:8302859, PMID:11432854]. This replication role is genetically essential and conserved across species: the S. pombe ortholog is required for DNA replication and is functionally complemented by both the S. cerevisiae and human RFC3 (hRFC36) proteins [PMID:10794172]. Consistent with its replication function, RFC3 is required for cell proliferation and S-phase progression, with knockdown arresting cells in S phase and altering expression of cell cycle regulators p21, p53, p57, and cyclin A across multiple cancer contexts [PMID:22328562, PMID:26397132, PMID:26464638]. RFC3 is transcriptionally activated by the YAP1/TEAD axis, which binds its promoter to drive tumor growth and metastasis [PMID:38383698], and it physically interacts with KIF14 to promote cancer cell proliferation, migration, and invasion [PMID:38590579]. Independently of replication, RFC3 acts as a host antiviral restriction factor downstream of an IRF2–FAM111A axis, limiting replication of orthopoxvirus and Zika virus [PMID:28320935, PMID:34930359].","teleology":[{"year":1994,"claim":"Established RFC3 as the 40-kDa subunit of the essential RF-C clamp loader and showed it is an intrinsic ATPase, answering what biochemical activity it contributes to replication.","evidence":"Molecular cloning, gene disruption, purification to homogeneity, and in vitro ATPase assays with defined nucleic acid substrates in yeast","pmids":["8302859"],"confidence":"High","gaps":["Did not resolve how the subunit assembles within the pentameric complex","Did not define structural basis of ssDNA-stimulated ATPase"]},{"year":2000,"claim":"Demonstrated cross-species functional conservation, showing the replication role of RFC3 is preserved from yeast to human.","evidence":"S. pombe gene disruption and heterologous complementation with S. cerevisiae Rfc3 and human hRFC36","pmids":["10794172"],"confidence":"High","gaps":["Did not characterize human RFC3 biochemistry directly","Did not address non-replication functions"]},{"year":2001,"claim":"Pinpointed the conserved Walker A lysine (K59) as the active-site residue coupling ATP binding to DNA recognition and PCNA loading, defining the mechanism of RFC3's contribution to clamp loading.","evidence":"Site-directed mutagenesis (K59E, K59R) combined with reconstituted ATPase, DNA binding, clamp loading, and PCNA interaction assays","pmids":["11432854"],"confidence":"High","gaps":["Did not resolve subunit-specific roles within the assembled clamp loader","Performed in yeast system"]},{"year":2015,"claim":"Linked RFC3 to S-phase progression and proliferation in cancer cells, showing its loss arrests the cell cycle and perturbs cell cycle regulators.","evidence":"Lentiviral shRNA knockdown with flow cytometry and western blot of p21/p53/p57/cyclin A in hepatocellular and ovarian carcinoma cells","pmids":["26397132","26464638","22328562"],"confidence":"Medium","gaps":["Cell cycle protein changes are correlative, not mechanistically dissected","Did not establish whether effects are downstream of replication clamp loading or a separate role"]},{"year":2017,"claim":"Revealed an unexpected antiviral role, placing the RFC complex including RFC3 as a host restriction factor against poxvirus downstream of IRF2–FAM111A.","evidence":"Genome-wide siRNA screen with secondary validation, viral replication/spread assays, and expression profiling","pmids":["28320935"],"confidence":"Medium","gaps":["Molecular mechanism of restriction not defined","Relationship between clamp loading and antiviral activity unresolved"]},{"year":2021,"claim":"Extended the IRF2–FAM111A–RFC3 restriction axis to Zika virus, generalizing RFC3's antiviral function.","evidence":"siRNA epistasis of IRF2/FAM111A/RFC3 with viral replication readouts across A549, 2FTGH, and U5A cells","pmids":["34930359"],"confidence":"Medium","gaps":["How RFC3 biochemically restricts viral replication is unknown","Direct interaction with FAM111A not demonstrated"]},{"year":2024,"claim":"Identified KIF14 as a physical partner and downstream effector, and YAP1/TEAD as a transcriptional activator, situating RFC3 in oncogenic signaling networks.","evidence":"Co-immunoprecipitation and KIF14 overexpression rescue in colorectal cancer; dual luciferase promoter reporter and shRNA knockdown with xenograft assays in gastric cancer","pmids":["38590579","38383698"],"confidence":"Medium","gaps":["KIF14 interaction rests on a single Co-IP without reciprocal validation","Mechanistic link between KIF14 binding and RFC3 replication function unclear"]},{"year":2025,"claim":"Connected RFC3 to chemotherapy resistance via ferroptosis, suggesting modulation of a Wnt/β-catenin/GPX4 axis.","evidence":"siRNA knockdown with oxaliplatin sensitivity, ferroptosis readouts, and immunoblot of pathway proteins in colorectal cancer cells","pmids":["39749364"],"confidence":"Low","gaps":["Mechanism inferred from immunoblot expression changes only, without direct pathway reconstitution","Causality between RFC3 and GPX4 axis not established"]},{"year":null,"claim":"How RFC3's core clamp-loading biochemistry mechanistically connects to its antiviral restriction and oncogenic signaling roles remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of human RFC3 within the assembled clamp loader in the corpus","Molecular basis of viral restriction undefined","Unknown whether non-replication functions require ATPase/clamp-loading activity"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140657","term_label":"ATP-dependent activity","supporting_discovery_ids":[0,1]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0,1]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[1]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,1]}],"pathway":[{"term_id":"R-HSA-69306","term_label":"DNA Replication","supporting_discovery_ids":[0,1,2]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[4,5]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[6,7]}],"complexes":["Replication Factor C (RF-C) clamp loader"],"partners":["PCNA","KIF14","FAM111A"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P40938","full_name":"Replication factor C subunit 3","aliases":["Activator 1 38 kDa subunit","A1 38 kDa subunit","Activator 1 subunit 3","Replication factor C 38 kDa subunit","RF-C 38 kDa subunit","RFC38"],"length_aa":356,"mass_kda":40.6,"function":"Subunit of the replication factor C (RFC) complex which acts during elongation of primed DNA templates by DNA polymerases delta and epsilon, and is necessary for ATP-dependent loading of proliferating cell nuclear antigen (PCNA) onto primed DNA","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/P40938/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/RFC3","classification":"Common Essential","n_dependent_lines":1200,"n_total_lines":1208,"dependency_fraction":0.9933774834437086},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"NPM1","stoichiometry":0.2},{"gene":"PARP1","stoichiometry":0.2},{"gene":"RAD17","stoichiometry":0.2},{"gene":"SSRP1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/RFC3","total_profiled":1310},"omim":[{"mim_id":"613203","title":"DNA REPLICATION AND SISTER CHROMATID COHESION 1; DSCC1","url":"https://www.omim.org/entry/613203"},{"mim_id":"613202","title":"CHROMOSOME TRANSMISSION FIDELITY FACTOR 8; CHTF8","url":"https://www.omim.org/entry/613202"},{"mim_id":"613201","title":"CHROMOSOME TRANSMISSION FIDELITY FACTOR 18; CHTF18","url":"https://www.omim.org/entry/613201"},{"mim_id":"600407","title":"REPLICATION FACTOR C, SUBUNIT 5; RFC5","url":"https://www.omim.org/entry/600407"},{"mim_id":"600405","title":"REPLICATION FACTOR C, SUBUNIT 3; RFC3","url":"https://www.omim.org/entry/600405"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"},{"location":"Vesicles","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/RFC3"},"hgnc":{"alias_symbol":["RFC38","MGC5276"],"prev_symbol":[]},"alphafold":{"accession":"P40938","domains":[{"cath_id":"3.40.50.300","chopping":"3-182","consensus_level":"high","plddt":84.6372,"start":3,"end":182},{"cath_id":"1.20.272.10","chopping":"249-347","consensus_level":"high","plddt":90.2367,"start":249,"end":347},{"cath_id":"1.10.8","chopping":"188-235","consensus_level":"high","plddt":90.4229,"start":188,"end":235}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P40938","model_url":"https://alphafold.ebi.ac.uk/files/AF-P40938-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P40938-F1-predicted_aligned_error_v6.png","plddt_mean":87.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RFC3","jax_strain_url":"https://www.jax.org/strain/search?query=RFC3"},"sequence":{"accession":"P40938","fasta_url":"https://rest.uniprot.org/uniprotkb/P40938.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P40938/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P40938"}},"corpus_meta":[{"pmid":"29593432","id":"PMC_29593432","title":"Downregulation of hsa_circ_0011946 suppresses the migration and invasion of the breast cancer cell line MCF-7 by targeting RFC3.","date":"2018","source":"Cancer management and research","url":"https://pubmed.ncbi.nlm.nih.gov/29593432","citation_count":69,"is_preprint":false},{"pmid":"8302859","id":"PMC_8302859","title":"Molecular cloning and expression of the Saccharomyces cerevisiae RFC3 gene, an essential component of replication factor C.","date":"1994","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/8302859","citation_count":61,"is_preprint":false},{"pmid":"11432854","id":"PMC_11432854","title":"ATP utilization by yeast replication factor C. III. The ATP-binding domains of Rfc2, Rfc3, and Rfc4 are essential for DNA recognition and clamp loading.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11432854","citation_count":58,"is_preprint":false},{"pmid":"7774928","id":"PMC_7774928","title":"Assignment of the 36.5-kDa (RFC5), 37-kDa (RFC4), 38-kDa (RFC3), and 40-kDa (RFC2) subunit genes of human replication factor C to chromosome bands 12q24.2-q24.3, 3q27, 13q12.3-q13, and 7q11.23.","date":"1995","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/7774928","citation_count":40,"is_preprint":false},{"pmid":"22328562","id":"PMC_22328562","title":"Integrative genomics identified RFC3 as an amplified candidate oncogene in esophageal adenocarcinoma.","date":"2012","source":"Clinical cancer research : an official journal of the American Association for Cancer 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Purified Rfc3p displays ATPase activity that is markedly stimulated by single-stranded DNA but not by double-stranded DNA or RNA.\",\n      \"method\": \"Molecular cloning, gene disruption (essential gene), overexpression in E. coli, purification to homogeneity, in vitro ATPase assay\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro biochemical reconstitution with purified protein, ATPase assay with defined substrates, genetic essentiality demonstrated\",\n      \"pmids\": [\"8302859\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The conserved Walker A lysine (K59) in the ATP-binding domain of yeast Rfc3 is essential for ATPase activity, DNA binding, and clamp (PCNA) loading. A rfc3-K59E mutation severely impairs ATP hydrolysis, DNA binding, and clamp loading activity. A conservative rfc3-K59R mutation shows only mild clamp loading defects that are fully suppressed at high ATP concentrations, indicating Rfc3's ATP-binding domain is critical for DNA recognition and PCNA loading.\",\n      \"method\": \"Site-directed mutagenesis of Walker A motif, overexpression in E. coli, in vitro ATPase assay, clamp loading assay, DNA binding assay, PCNA interaction assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — active-site mutagenesis combined with multiple in vitro biochemical assays (ATPase, clamp loading, DNA binding, PCNA interaction) in reconstituted system\",\n      \"pmids\": [\"11432854\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"The S. pombe rfc3+ gene encodes an ortholog of S. cerevisiae Rfc3 and human hRFC36. It is essential for DNA replication; rfc3Δ cells are defective for DNA replication. Heterologous expression of either S. cerevisiae Rfc3 or human hRFC36 rescues the loss of S. pombe rfc3+ function, demonstrating functional conservation across species.\",\n      \"method\": \"Gene cloning, gene disruption (essential gene), heterologous complementation with S. cerevisiae Rfc3 and human hRFC36\",\n      \"journal\": \"Current genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic essentiality and cross-species complementation establish conserved role in DNA replication\",\n      \"pmids\": [\"10794172\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"RFC3 knockdown inhibits proliferation and anchorage-independent growth of cancer cells with increased RFC3 copy number, establishing RFC3 as functionally required for proliferation in a copy-number-dependent manner (candidate oncogene in esophageal adenocarcinoma).\",\n      \"method\": \"RFC3 knockdown (siRNA/shRNA), cell proliferation assay, anchorage-independent growth assay, comparative genomic hybridization, gene expression integration\",\n      \"journal\": \"Clinical cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KD with defined cellular phenotype (proliferation, anchorage-independent growth), copy-number dependency established, single lab\",\n      \"pmids\": [\"22328562\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"shRNA-mediated knockdown of RFC3 in hepatocellular carcinoma cells suppresses cell viability and proliferation, and arrests the cell cycle in S phase, partly by regulating expression of cell cycle-related proteins p21, p53, p57, and cyclin A.\",\n      \"method\": \"Lentivirus-mediated shRNA knockdown, MTS assay, cell growth assay, flow cytometry (cell cycle), western blot (p21, p53, p57, cyclin A)\",\n      \"journal\": \"International journal of molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KD with defined cellular phenotype and molecular readout (cell cycle proteins), two orthogonal methods, single lab\",\n      \"pmids\": [\"26397132\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"shRNA-mediated knockdown of RFC3 in ovarian cancer OVCAR-3 cells suppresses cell viability and proliferation, arrests the cell cycle in S phase, and induces apoptosis.\",\n      \"method\": \"Lentivirus-mediated shRNA knockdown, MTS assay, cell growth assay, flow cytometry (cell cycle, apoptosis)\",\n      \"journal\": \"International journal of clinical and experimental pathology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KD with defined cellular phenotype (S-phase arrest, apoptosis), two orthogonal methods, single lab\",\n      \"pmids\": [\"26464638\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"RFC3 (and the RFC complex broadly) acts as a host restriction factor limiting orthopoxvirus SPI-1 deletion mutant replication in human cells. siRNA depletion of RFC3 (and RFC1, RFC2, RFC4, RFC5) significantly enhances replication and spread of the SPI-1 mutant virus, identifying RFC complex as an antiviral restriction factor. IRF2 regulates basal expression of FAM111A, which in turn enhances the host restriction effect of RFC3 on poxvirus replication.\",\n      \"method\": \"Genome-wide siRNA screen, secondary siRNA validation, virus replication/spread assays, microarray, quantitative RT-PCR, immunoblotting\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genome-wide siRNA screen confirmed by secondary assays, multiple RFC subunit siRNAs tested, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"28320935\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"IRF2 inhibits Zika virus (ZIKV) replication by activating FAM111A expression, which in turn enhances the host restriction effect of RFC3. siRNA knockdown of RFC3 in ZIKV-infected cells reduces restriction of viral replication, placing RFC3 downstream of the IRF2–FAM111A axis in antiviral defense.\",\n      \"method\": \"siRNA knockdown of IRF2, FAM111A, and RFC3; overexpression of IRF2; RT-qPCR; western blot; viral replication assays in A549, 2FTGH, and U5A cells\",\n      \"journal\": \"Virology journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis established by siRNA knockdown of pathway components with viral replication readout, single lab, multiple cell lines\",\n      \"pmids\": [\"34930359\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"RFC3 physically interacts with KIF14 (kinesin family member 14) in colorectal cancer cells, as demonstrated by co-immunoprecipitation. RFC3 depletion reduces KIF14 expression, and KIF14 overexpression reverses the anti-proliferative, anti-migratory, anti-invasive, and anti-angiogenic effects of RFC3 knockdown, placing KIF14 downstream of RFC3 in CRC malignant progression.\",\n      \"method\": \"Co-immunoprecipitation, siRNA knockdown, KIF14 overexpression rescue experiment, CCK-8 assay, EdU assay, flow cytometry, wound healing assay, Transwell assay, tube formation assay, western blot\",\n      \"journal\": \"Experimental and therapeutic medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — single Co-IP for interaction, but rescue experiment with KIF14 overexpression provides epistasis support; single lab, multiple orthogonal cellular assays\",\n      \"pmids\": [\"38590579\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"The YAP1/TEAD signaling axis transcriptionally activates RFC3 expression by binding to the RFC3 promoter. YAP1/TEAD-driven RFC3 upregulation promotes gastric cancer cell proliferation, migration, invasion, and in vivo tumor growth and metastasis.\",\n      \"method\": \"Dual luciferase reporter assay (YAP1/TEAD binding to RFC3 promoter), lentivirus-mediated shRNA knockdown of RFC3, in vitro cell assays, in vivo xenograft/metastasis assays\",\n      \"journal\": \"International journal of clinical oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — dual luciferase reporter assay establishes transcriptional regulation, supported by KD cellular phenotypes and in vivo data; single lab\",\n      \"pmids\": [\"38383698\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"RFC3 knockdown in colorectal cancer cells enhances sensitivity to oxaliplatin by inducing ferroptosis. The mechanism involves disruption of the Wnt/β-catenin/GPX4 signaling axis, as assessed by immunoblot analysis of pathway components.\",\n      \"method\": \"siRNA knockdown, cell viability assay, clonogenic survival assay, flow cytometry, immunoblot (Wnt/β-catenin/GPX4 axis proteins), ferroptosis readouts\",\n      \"journal\": \"Fundamental & clinical pharmacology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single method for pathway (immunoblot only), mechanism inferred from protein expression changes without direct pathway reconstitution\",\n      \"pmids\": [\"39749364\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RFC3 encodes a subunit of the heteropentameric Replication Factor C (RFC) clamp loader complex; its conserved Walker A ATP-binding domain (K59 in yeast) is essential for ATPase activity, DNA recognition, and PCNA clamp loading onto DNA to enable processive replication by DNA polymerases delta and epsilon. Beyond its core replication function, RFC3 participates in cell cycle progression (S-phase regulation involving p21, p53, p57, and cyclin A), acts as a host restriction factor for poxviruses and ZIKV downstream of an IRF2–FAM111A axis, physically interacts with KIF14 to drive cancer cell proliferation and invasion, and is transcriptionally activated by the YAP1/TEAD signaling pathway in gastric cancer.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RFC3 encodes a subunit of the heteropentameric Replication Factor C (RF-C) clamp loader, an essential complex required for processive DNA replication by DNA polymerases delta and epsilon [#0]. The purified protein displays ATPase activity strongly stimulated by single-stranded DNA, and its conserved Walker A lysine (K59) is essential for ATP hydrolysis, DNA binding, and loading of the PCNA clamp onto DNA [#0, #1]. This replication role is genetically essential and conserved across species: the S. pombe ortholog is required for DNA replication and is functionally complemented by both the S. cerevisiae and human RFC3 (hRFC36) proteins [#2]. Consistent with its replication function, RFC3 is required for cell proliferation and S-phase progression, with knockdown arresting cells in S phase and altering expression of cell cycle regulators p21, p53, p57, and cyclin A across multiple cancer contexts [#3, #4, #5]. RFC3 is transcriptionally activated by the YAP1/TEAD axis, which binds its promoter to drive tumor growth and metastasis [#9], and it physically interacts with KIF14 to promote cancer cell proliferation, migration, and invasion [#8]. Independently of replication, RFC3 acts as a host antiviral restriction factor downstream of an IRF2\\u2013FAM111A axis, limiting replication of orthopoxvirus and Zika virus [#6, #7].\",\n  \"teleology\": [\n    {\n      \"year\": 1994,\n      \"claim\": \"Established RFC3 as the 40-kDa subunit of the essential RF-C clamp loader and showed it is an intrinsic ATPase, answering what biochemical activity it contributes to replication.\",\n      \"evidence\": \"Molecular cloning, gene disruption, purification to homogeneity, and in vitro ATPase assays with defined nucleic acid substrates in yeast\",\n      \"pmids\": [\"8302859\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve how the subunit assembles within the pentameric complex\", \"Did not define structural basis of ssDNA-stimulated ATPase\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Demonstrated cross-species functional conservation, showing the replication role of RFC3 is preserved from yeast to human.\",\n      \"evidence\": \"S. pombe gene disruption and heterologous complementation with S. cerevisiae Rfc3 and human hRFC36\",\n      \"pmids\": [\"10794172\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not characterize human RFC3 biochemistry directly\", \"Did not address non-replication functions\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Pinpointed the conserved Walker A lysine (K59) as the active-site residue coupling ATP binding to DNA recognition and PCNA loading, defining the mechanism of RFC3's contribution to clamp loading.\",\n      \"evidence\": \"Site-directed mutagenesis (K59E, K59R) combined with reconstituted ATPase, DNA binding, clamp loading, and PCNA interaction assays\",\n      \"pmids\": [\"11432854\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve subunit-specific roles within the assembled clamp loader\", \"Performed in yeast system\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Linked RFC3 to S-phase progression and proliferation in cancer cells, showing its loss arrests the cell cycle and perturbs cell cycle regulators.\",\n      \"evidence\": \"Lentiviral shRNA knockdown with flow cytometry and western blot of p21/p53/p57/cyclin A in hepatocellular and ovarian carcinoma cells\",\n      \"pmids\": [\"26397132\", \"26464638\", \"22328562\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Cell cycle protein changes are correlative, not mechanistically dissected\", \"Did not establish whether effects are downstream of replication clamp loading or a separate role\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Revealed an unexpected antiviral role, placing the RFC complex including RFC3 as a host restriction factor against poxvirus downstream of IRF2\\u2013FAM111A.\",\n      \"evidence\": \"Genome-wide siRNA screen with secondary validation, viral replication/spread assays, and expression profiling\",\n      \"pmids\": [\"28320935\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism of restriction not defined\", \"Relationship between clamp loading and antiviral activity unresolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Extended the IRF2\\u2013FAM111A\\u2013RFC3 restriction axis to Zika virus, generalizing RFC3's antiviral function.\",\n      \"evidence\": \"siRNA epistasis of IRF2/FAM111A/RFC3 with viral replication readouts across A549, 2FTGH, and U5A cells\",\n      \"pmids\": [\"34930359\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How RFC3 biochemically restricts viral replication is unknown\", \"Direct interaction with FAM111A not demonstrated\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified KIF14 as a physical partner and downstream effector, and YAP1/TEAD as a transcriptional activator, situating RFC3 in oncogenic signaling networks.\",\n      \"evidence\": \"Co-immunoprecipitation and KIF14 overexpression rescue in colorectal cancer; dual luciferase promoter reporter and shRNA knockdown with xenograft assays in gastric cancer\",\n      \"pmids\": [\"38590579\", \"38383698\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"KIF14 interaction rests on a single Co-IP without reciprocal validation\", \"Mechanistic link between KIF14 binding and RFC3 replication function unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Connected RFC3 to chemotherapy resistance via ferroptosis, suggesting modulation of a Wnt/\\u03b2-catenin/GPX4 axis.\",\n      \"evidence\": \"siRNA knockdown with oxaliplatin sensitivity, ferroptosis readouts, and immunoblot of pathway proteins in colorectal cancer cells\",\n      \"pmids\": [\"39749364\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Mechanism inferred from immunoblot expression changes only, without direct pathway reconstitution\", \"Causality between RFC3 and GPX4 axis not established\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How RFC3's core clamp-loading biochemistry mechanistically connects to its antiviral restriction and oncogenic signaling roles remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of human RFC3 within the assembled clamp loader in the corpus\", \"Molecular basis of viral restriction undefined\", \"Unknown whether non-replication functions require ATPase/clamp-loading activity\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140657\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-69306\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [4, 5]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [6, 7]}\n    ],\n    \"complexes\": [\"Replication Factor C (RF-C) clamp loader\"],\n    \"partners\": [\"PCNA\", \"KIF14\", \"FAM111A\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}