{"gene":"E4F1","run_date":"2026-04-28T17:46:03","timeline":{"discoveries":[{"year":1987,"finding":"E4F1 binds to two sites within the adenovirus E4 enhancer and one site directly upstream of the E4 TATA box, and this binding is required for constitutive transcriptional activity of the E4 promoter in vitro.","method":"In vitro transcription assay, DNA-binding assay, site-directed mutagenesis of binding sites","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 — in vitro reconstitution with functional mutagenesis, foundational paper with 184 citations","pmids":["2956091"],"is_preprint":false},{"year":1989,"finding":"E4F DNA-binding activity is regulated by phosphorylation; alkaline phosphatase treatment abolishes E4F binding activity, and incubation of inactivated E4F with extract from virus-infected cells restores activity. E4F was purified as a single 50 kDa polypeptide.","method":"Affinity purification, alkaline phosphatase treatment, in vitro binding assay","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 1 — in vitro biochemical reconstitution with phosphatase and extract rescue, 100 citations","pmids":["2545525"],"is_preprint":false},{"year":1990,"finding":"E4F, but not ATF, confers E1A-dependent transcriptional inducibility to the E4 promoter; E4F forms a stable complex with E4 promoter DNA whereas ATF dissociates rapidly, and E4F activity (but not ATF) is markedly increased upon adenovirus infection.","method":"Cotransfection assay, DNA-binding competition assay, promoter mutagenesis","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1–2 — functional promoter assays plus binding discrimination, replicated in subsequent studies","pmids":["2169022"],"is_preprint":false},{"year":1992,"finding":"E1A-mediated activation of the E4 promoter via E4F is dependent on the carboxy-terminal auxiliary regions (AR1 and AR2) of E1A; activation of E4F, but not ATF-2, requires these regions, placing E4F downstream of E1A CR3/AR elements.","method":"Transient transfection assay with E1A deletion mutants, DNA-binding assay","journal":"The EMBO journal","confidence":"Medium","confidence_rationale":"Tier 2 — genetic dissection via E1A mutagenesis with functional readout in single study","pmids":["1387083"],"is_preprint":false},{"year":1997,"finding":"E4F is generated as a 50 kDa N-terminal fragment from the full-length 783-amino-acid E4F1 protein (human homolog of murine phiAP3), which contains a zinc finger domain; E1A(13S) differentially regulates the two forms via phosphorylation, stimulating DNA-binding of the 50 kDa fragment while reducing that of the full-length protein.","method":"Expression cloning, immunological characterization, phosphatase sensitivity assay, transient transfection","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1–2 — cDNA cloning with biochemical and functional validation, multiple orthogonal methods","pmids":["9121437"],"is_preprint":false},{"year":2004,"finding":"E4F1 (p120 E4F) physically interacts with the tumor suppressor RASSF1A in yeast and mammalian cells, forming a complex in vivo; RASSF1A enhances G1 cell cycle arrest and S-phase inhibition induced by p120(E4F).","method":"Yeast two-hybrid, in vitro pull-down, co-immunoprecipitation, siRNA knockdown of RASSF1A, propidium iodide cell cycle analysis","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 — reciprocal Co-IP plus in vitro pull-down and functional rescue with siRNA, single lab","pmids":["14729613"],"is_preprint":false},{"year":2004,"finding":"E4F1 is required for mitotic progression during embryonic cell cycles; E4F knockout mice die at peri-implantation stage and E4F-/- blastocysts show chromosomal missegregation and increased apoptosis; E4F localizes to the mitotic spindle during M phase.","method":"Gene targeting (knockout mice), live-cell imaging/immunofluorescence of mitotic spindle localization, blastocyst culture","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 — genetic KO with defined mitotic phenotype plus direct localization to spindle, multiple orthogonal readouts","pmids":["15226446"],"is_preprint":false},{"year":2006,"finding":"E4F1 is an atypical E3 ubiquitin ligase for p53 that stimulates oligo-ubiquitylation of p53 in its hinge region on lysine residues distinct from those targeted by Hdm2; E4F1-dependent Ub-p53 conjugates are chromatin-associated and promote a p53-dependent transcriptional program leading to cell cycle arrest but not apoptosis. E4F1 and PCAF mediate mutually exclusive modifications at the same lysines.","method":"In vitro ubiquitylation assay, co-immunoprecipitation, chromatin fractionation, mutagenesis of p53 lysines, transcriptional reporter assays","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1 — in vitro reconstitution of E3 ligase activity plus mutagenesis plus chromatin association, multiple orthogonal methods, 181 citations","pmids":["17110336"],"is_preprint":false},{"year":2006,"finding":"E4F1 interacts physically and genetically with BMI1 in hematopoietic cells; shRNA knockdown of E4f1 rescues the clonogenic and repopulating defects of Bmi1-/- hematopoietic cells independently of INK4A/ARF and p53.","method":"Co-immunoprecipitation, RNA interference knockdown, hematopoietic transplantation assay, colony assay","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 2 — physical interaction confirmed plus genetic epistasis in transplantation rescue, multiple methods","pmids":["16882984"],"is_preprint":false},{"year":2006,"finding":"Full-length E4F1 (p120) but not its truncated form (p50) directly interacts with the LIM-only protein FHL2 in the nuclear compartment; FHL2 binding inhibits E4F1's capacity to repress transcription and block cell proliferation, and reduces nuclear E4F1-p53 complexes.","method":"In vitro pull-down, co-immunoprecipitation, transcriptional reporter assay, cell proliferation assay, subcellular fractionation","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 — in vitro and in vivo binding plus functional transcriptional and proliferation readouts, single lab","pmids":["16652157"],"is_preprint":false},{"year":2007,"finding":"E4F1 forms a complex with LANP (an INHAT corepressor) and modulates transcriptional repression; ataxin 1 relieves this repression by competing with E4F1 for LANP binding.","method":"Co-immunoprecipitation, transcriptional reporter assay, competition binding assay","journal":"EMBO reports","confidence":"Medium","confidence_rationale":"Tier 2–3 — Co-IP plus functional transcriptional assay, single lab","pmids":["17557114"],"is_preprint":false},{"year":2010,"finding":"E4F1 is required for epidermal stem cell (ESC) maintenance and skin homeostasis; E4F1 conditional KO in basal keratinocytes depletes the ESC pool; clonogenic potential of E4F1 KO ESCs is rescued by Bmi1 overexpression or Ink4a/Arf or p53 depletion, placing E4F1 in the Bmi1-Arf-p53 pathway.","method":"Conditional knockout mouse, ex vivo clonogenic assay, genetic rescue by Bmi1 overexpression and Ink4a/Arf or p53 deletion","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 — conditional KO with cell-autonomous phenotype and genetic epistasis rescue, multiple orthogonal approaches","pmids":["21088222"],"is_preprint":false},{"year":2011,"finding":"E4F1 inactivation in myeloid leukemic cells causes mitochondrial defects, increased ROS production, and massive autophagic cell death, without affecting normal primary macrophages; this establishes E4F1 as essential for survival of transformed myeloid cells through mitochondrial function.","method":"Cre-mediated conditional E4F1 deletion in mouse leukemia model, ROS measurement, mitochondrial function assay, shRNA in human leukemic cell lines","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 2 — in vivo genetic deletion plus in vitro mechanistic follow-up with ROS and mitochondrial assays, multiple cell types","pmids":["21708927"],"is_preprint":false},{"year":2015,"finding":"E4F1 directly controls transcription of Chek1 (CHK1) and genes involved in mitochondrial function; E4F1 inactivation in p53-deficient transformed cells causes CHK1-dependent checkpoint deficiency, mitochondrial dysfunction, increased ROS, energy stress, inhibition of pyrimidine synthesis, and cell death.","method":"ChIP-seq, RNA-seq, conditional E4F1 KO, CHK1 functional assays, metabolic measurements (ROS, ATP, pyrimidine synthesis)","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 1–2 — ChIP-seq identifies direct genomic targets, KO phenotype validated with multiple metabolic and signaling readouts","pmids":["25843721"],"is_preprint":false},{"year":2015,"finding":"E4F1 physically interacts with and protects CHK1 protein from proteasomal degradation; E4f1-deficient hematopoietic cells accumulate DNA damage and show S-phase and mitotic defects that are fully rescued by ectopic Chek1 expression.","method":"Co-immunoprecipitation, conditional E4f1 KO, ectopic Chek1 rescue experiment, DNA damage markers, flow cytometry cell cycle analysis","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 — Co-IP plus genetic rescue by Chek1 re-expression, multiple orthogonal readouts","pmids":["25843717"],"is_preprint":false},{"year":2016,"finding":"E4F1 transcriptionally controls four genes (Dlat, Dld, Mpc1, Slc25a19) involved in pyruvate oxidation; E4F1 loss results in ~80% decrease in pyruvate dehydrogenase (PDH) activity and altered pyruvate metabolism; muscle-specific E4F1 KO mice show low PDH activity, endurance defects, and lactic acidemia rescued by PDH stimulation or ketogenic diet.","method":"ChIP-seq, conditional muscle-specific KO mouse, PDH enzymatic activity assay, metabolic flux analysis, pharmacological rescue","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1–2 — ChIP-seq identifies direct targets, KO mouse with enzymatic activity measurement, pharmacological rescue validates mechanism","pmids":["27621446"],"is_preprint":false},{"year":2016,"finding":"E4F1 transcriptionally regulates Dlat (E2 subunit of PDH complex) in keratinocytes; E4f1 KO keratinocytes show impaired PDH activity and redirection of glycolytic flux to lactate; shRNA depletion of Dlat recapitulates E4f1 KO defects including impaired clonogenic potential.","method":"Conditional KO keratinocytes, PDH activity assay, metabolic flux measurement, shRNA knockdown of Dlat, clonogenic assay","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1–2 — enzymatic activity assay plus genetic epistasis (Dlat shRNA phenocopy), multiple orthogonal methods","pmids":["27621431"],"is_preprint":false},{"year":2020,"finding":"The p50E4F1 transcription regulatory region stably associates with E1A289R in vivo via E1A CR3; multiple cellular proteins including TBP bind the p50E4F1 TR region in vitro; trans-activation is promoter-specific and requires both E1A CR3 and N-terminal domains.","method":"Co-immunoprecipitation (in vivo), in vitro binding assay with TBP, GAL4-fusion transcriptional assays","journal":"Gene","confidence":"Medium","confidence_rationale":"Tier 2–3 — in vivo and in vitro binding combined with functional reporter assays, single lab","pmids":["32535047"],"is_preprint":false},{"year":2021,"finding":"E4F1 is rapidly recruited to DNA double-strand breaks in a PARP-dependent manner, promotes ATR/CHK1 signaling and DNA-end resection, and facilitates homologous recombination; E4F1 binds the chromatin remodeler BRG1/SMARCA4 and together with PARP-1 mediates BRG1 recruitment to DNA lesions.","method":"Live-cell imaging of DSB recruitment, Co-immunoprecipitation of E4F1-BRG1-PARP-1, HR reporter assay, DNA resection assay, CHK1 signaling analysis","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (live imaging, Co-IP, functional HR assay), identifies molecular complex","pmids":["33692124"],"is_preprint":false},{"year":2021,"finding":"E4F1 directly interacts with p53 and they are co-recruited to the Stearoyl-CoA Desaturase-1 (SCD1) locus in adipocytes to regulate monounsaturated fatty acid synthesis; E4F1 inactivation activates a p53-dependent transcriptional program for lipid metabolism.","method":"Co-immunoprecipitation, ChIP assay at SCD1 locus, conditional adipose E4F1 KO mouse, metabolic phenotyping, genetic rescue by p53 inactivation","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 — Co-IP plus ChIP at specific locus plus KO mouse with genetic rescue, multiple orthogonal methods","pmids":["34857760"],"is_preprint":false},{"year":2022,"finding":"E4F1 binds the promoters of CHEK1, TTI2, and PPP5C in triple-negative breast cancer cells and regulates the entire ATM/ATR-CHK1 axis at multiple levels; E4F1 depletion strongly reduces CHK1, ATM, and ATR protein levels and signaling, sensitizing cells to gemcitabine and cisplatin.","method":"ChIP-seq, RNA-seq, shRNA knockdown, PDX ChIP validation, DNA damage response assays, drug sensitivity assays","journal":"International journal of molecular sciences","confidence":"High","confidence_rationale":"Tier 2 — ChIP-seq with in vivo PDX validation, functional signaling and drug response readouts, multiple orthogonal approaches","pmids":["36012478"],"is_preprint":false},{"year":2023,"finding":"E4F1 binds specifically to the -57A>C mutant TERT promoter sequence and activates TERT transcription and telomerase activity; ZNF148 binds the wild-type TERT promoter at position 124 and also activates TERT.","method":"Proteomics-based DNA pulldown screen, ChIP assay, TERT reporter assay, telomerase activity assay","journal":"Genome research","confidence":"Medium","confidence_rationale":"Tier 2 — proteomics screen plus ChIP plus functional reporter and telomerase activity assays, single lab","pmids":["37918959"],"is_preprint":false},{"year":2025,"finding":"E4F1 directly transcriptionally regulates both Dlat (PDC subunit) and Elp3 (Elongator complex subunit), coordinating AcCoA production by PDC with tRNA acetylation at wobble uridine 34 by Elongator; this coupling ensures translation fidelity and neuronal survival during brain development.","method":"Conditional KO mouse model, primary neuronal cells, ChIP assay at Dlat and Elp3 promoters, tRNA modification analysis, translation fidelity assay, PDH activity measurement","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1–2 — genetic KO plus direct ChIP at two target loci plus biochemical validation of tRNA modification and translation fidelity, multiple orthogonal methods","pmids":["39747033"],"is_preprint":false}],"current_model":"E4F1 is a multifunctional zinc-finger transcription factor and atypical E3 ubiquitin ligase that: (1) binds specific promoter elements to directly regulate transcription of genes controlling pyruvate dehydrogenase complex activity (Dlat, Dld, Mpc1, Slc25a19), CHK1-mediated checkpoint signaling (Chek1, TTI2, PPP5C), and Elongator-mediated tRNA acetylation (Elp3); (2) oligo-ubiquitylates p53 in its hinge region on lysines distinct from Hdm2 targets, promoting chromatin-associated Ub-p53 and cell cycle arrest rather than apoptosis; (3) interacts with and stabilizes CHK1 protein from degradation; (4) is recruited to DNA double-strand breaks in a PARP-dependent manner and facilitates homologous recombination by mediating BRG1/SMARCA4 chromatin remodeler recruitment; and (5) physically interacts with key regulators including BMI1, RASSF1A, FHL2, LANP, and p53 to coordinate cell proliferation, stem cell maintenance, and metabolic homeostasis."},"narrative":{"teleology":[{"year":1987,"claim":"Identification of E4F1 as a sequence-specific DNA-binding factor required for adenovirus E4 promoter transcription established its founding activity as a transcriptional regulator.","evidence":"In vitro transcription and DNA-binding assays with site-directed mutagenesis of E4 promoter elements","pmids":["2956091"],"confidence":"High","gaps":["Cellular gene targets unknown","No information on endogenous function"]},{"year":1989,"claim":"Demonstration that E4F DNA-binding activity requires phosphorylation—abolished by phosphatase and restored by viral extract—revealed post-translational regulation as a key control mechanism.","evidence":"Alkaline phosphatase inactivation and rescue with adenovirus-infected cell extract; purification as 50 kDa polypeptide","pmids":["2545525"],"confidence":"High","gaps":["Kinase identity unknown","Phosphorylation sites not mapped"]},{"year":1997,"claim":"Cloning the full-length 783-residue E4F1 protein and showing that the 50 kDa form is an N-terminal cleavage product with distinct phosphorylation-dependent regulation resolved the molecular identity of the two E4F species.","evidence":"Expression cloning, immunological characterization, phosphatase sensitivity assays, transient transfection","pmids":["9121437"],"confidence":"High","gaps":["Protease responsible for p50 generation not identified","Relative functions of p50 vs p120 in endogenous context unclear"]},{"year":2004,"claim":"Discovery that E4F1 knockout mice die at peri-implantation with chromosomal missegregation and that E4F1 localizes to the mitotic spindle demonstrated an essential cell-autonomous role beyond transcription.","evidence":"Gene targeting in mice, live-cell imaging/immunofluorescence of spindle localization, blastocyst culture","pmids":["15226446"],"confidence":"High","gaps":["Mechanism of spindle association unknown","Whether mitotic role is direct or transcription-dependent not resolved"]},{"year":2006,"claim":"Identification of E4F1 as an atypical E3 ubiquitin ligase that oligo-ubiquitylates p53 on hinge-region lysines, producing chromatin-associated Ub-p53 that drives cell-cycle arrest rather than apoptosis, revealed a second enzymatic activity distinct from its transcription factor function.","evidence":"In vitro ubiquitylation reconstitution, p53 lysine mutagenesis, chromatin fractionation, transcriptional reporter assays","pmids":["17110336"],"confidence":"High","gaps":["Structural basis of E3 activity not determined","Ubiquitin chain topology not fully characterized","In vivo physiological importance of Ub-p53 pathway not genetically tested"]},{"year":2006,"claim":"Physical and genetic interaction with BMI1 in hematopoietic cells—where E4F1 knockdown rescues Bmi1−/− stem cell defects independently of INK4A/ARF and p53—placed E4F1 in the polycomb pathway controlling stem cell self-renewal.","evidence":"Co-immunoprecipitation, shRNA knockdown, hematopoietic transplantation and colony assays in Bmi1−/− cells","pmids":["16882984"],"confidence":"High","gaps":["Nature of E4F1-BMI1 antagonism at chromatin level unresolved","Direct transcriptional targets mediating rescue unknown"]},{"year":2010,"claim":"Conditional knockout in basal keratinocytes showed E4F1 is required for epidermal stem cell maintenance and that its loss is rescued by Bmi1 overexpression or Ink4a/Arf/p53 deletion, extending the E4F1-BMI1-p53 axis to somatic stem cell compartments.","evidence":"Conditional KO mouse, ex vivo clonogenic assays, genetic rescue experiments","pmids":["21088222"],"confidence":"High","gaps":["Whether metabolic or checkpoint targets mediate the stem cell phenotype not dissected"]},{"year":2015,"claim":"ChIP-seq and functional studies revealed that E4F1 directly controls Chek1 transcription and physically stabilizes CHK1 protein from degradation, unifying its checkpoint and DNA damage roles through dual transcriptional and post-translational control of a single target.","evidence":"ChIP-seq, conditional KO, ectopic Chek1 rescue of hematopoietic phenotype, co-immunoprecipitation","pmids":["25843721","25843717"],"confidence":"High","gaps":["Mechanism by which E4F1 prevents CHK1 proteasomal degradation not defined","Whether E4F1 ubiquitylates CHK1 or acts as a scaffold not tested"]},{"year":2016,"claim":"Identification of Dlat, Dld, Mpc1, and Slc25a19 as direct E4F1 targets established E4F1 as a master transcriptional regulator of pyruvate dehydrogenase complex activity and mitochondrial pyruvate oxidation, explaining the metabolic defects seen upon E4F1 loss.","evidence":"ChIP-seq, muscle-specific conditional KO, PDH enzymatic activity assays, metabolic flux analysis, pharmacological and dietary rescue","pmids":["27621446","27621431"],"confidence":"High","gaps":["How E4F1 selectivity for metabolic vs checkpoint gene promoters is determined remains unclear","No structural basis for promoter recognition"]},{"year":2021,"claim":"Demonstration that E4F1 is recruited to DNA double-strand breaks in a PARP-dependent manner and mediates BRG1/SMARCA4 recruitment to promote homologous recombination revealed a direct chromatin-remodeling function at damage sites, beyond transcriptional checkpoint control.","evidence":"Live-cell DSB recruitment imaging, co-immunoprecipitation of E4F1-BRG1-PARP-1 complex, HR reporter and DNA resection assays","pmids":["33692124"],"confidence":"High","gaps":["Whether the E3 ligase activity is required at DSBs is unknown","Structural basis of PARP-dependent recruitment not resolved"]},{"year":2021,"claim":"Co-recruitment of E4F1 and p53 to the SCD1 locus in adipocytes, with p53 inactivation rescuing E4F1-KO lipid metabolic phenotypes, demonstrated that E4F1-p53 cooperation extends beyond cell cycle to lipid metabolism regulation.","evidence":"Co-immunoprecipitation, ChIP at SCD1 locus, conditional adipose E4F1 KO mouse, genetic rescue by p53 deletion","pmids":["34857760"],"confidence":"High","gaps":["Whether Ub-p53 or unmodified p53 mediates lipid transcription not distinguished","Full set of lipid metabolism targets not mapped"]},{"year":2022,"claim":"ChIP-seq in triple-negative breast cancer revealed E4F1 occupancy at CHEK1, TTI2, and PPP5C promoters, showing that E4F1 controls the ATM/ATR-CHK1 axis at multiple nodes and that its depletion sensitizes cancer cells to genotoxic agents.","evidence":"ChIP-seq, RNA-seq, shRNA knockdown, PDX validation, drug sensitivity assays","pmids":["36012478"],"confidence":"High","gaps":["Whether E4F1 is a general vulnerability across cancer types not established","Contribution of each individual target to chemosensitization not dissected"]},{"year":2025,"claim":"Discovery that E4F1 coordinates acetyl-CoA production (via Dlat) with tRNA wobble uridine acetylation (via Elp3) linked its metabolic and translational roles, showing that E4F1 couples substrate supply to the Elongator tRNA modification pathway essential for neuronal survival.","evidence":"Conditional KO mouse, ChIP at Dlat and Elp3 promoters, tRNA modification and translation fidelity assays, PDH activity measurement","pmids":["39747033"],"confidence":"High","gaps":["Whether E4F1-Elongator coupling operates in non-neuronal tissues is untested","Direct E4F1-Elongator physical interaction not demonstrated"]},{"year":null,"claim":"How E4F1 integrates its E3 ubiquitin ligase activity, transcriptional functions, and PARP-dependent DSB recruitment through a single protein—and whether these functions are cell-type-specifically partitioned—remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of E4F1 exists","The protease generating the p50 form is unidentified","Whether the E3 ligase domain is required for DSB repair or transcriptional functions is untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[0,2,13,15,16,20,22]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[7]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[0,1,4]},{"term_id":"GO:0016874","term_label":"ligase activity","supporting_discovery_ids":[7]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[6,9,18]},{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[7,18]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[6]}],"pathway":[{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[0,2,13,15,20,22]},{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[14,18,20]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[12,15,16,19,22]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[5,6,7,14]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[6,12]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[7]}],"complexes":[],"partners":["TP53","BMI1","CHEK1","SMARCA4","PARP1","RASSF1A","FHL2","LANP"],"other_free_text":[]},"mechanistic_narrative":"E4F1 is a zinc-finger transcription factor and atypical ubiquitin ligase that integrates metabolic homeostasis, DNA damage checkpoint signaling, chromatin remodeling, and stem cell maintenance. As a transcription factor, E4F1 directly binds promoters of genes controlling pyruvate dehydrogenase complex activity (Dlat, Dld, Mpc1, Slc25a19), the ATR/CHK1 checkpoint axis (Chek1, TTI2, PPP5C), and Elongator-mediated tRNA modification (Elp3), coupling acetyl-CoA production to translational fidelity during neuronal development [PMID:27621446, PMID:25843721, PMID:36012478, PMID:39747033]. E4F1 also functions as an atypical E3 ubiquitin ligase that oligo-ubiquitylates p53 on hinge-region lysines distinct from Hdm2 targets, generating chromatin-associated Ub-p53 species that selectively activate cell-cycle arrest rather than apoptosis [PMID:17110336]. Beyond transcription and ubiquitylation, E4F1 is recruited to DNA double-strand breaks in a PARP-dependent manner and facilitates homologous recombination by mediating BRG1/SMARCA4 chromatin-remodeler recruitment, while also physically stabilizing CHK1 protein against proteasomal degradation [PMID:33692124, PMID:25843717]."},"prefetch_data":{"uniprot":{"accession":"Q66K89","full_name":"Transcription factor E4F1","aliases":["E4F transcription factor 1","Putative E3 ubiquitin-protein ligase E4F1","RING-type E3 ubiquitin transferase E4F1","Transcription factor E4F","p120E4F","p50E4F"],"length_aa":784,"mass_kda":83.5,"function":"May function as a transcriptional repressor. May also function as a ubiquitin ligase mediating ubiquitination of chromatin-associated TP53. Functions in cell survival and proliferation through control of the cell cycle. Functions in the p53 and pRB tumor suppressor pathways and regulates the cyclin CCNA2 transcription Identified as a cellular target of the adenoviral oncoprotein E1A, it is required for both transcriptional activation and repression of viral genes","subcellular_location":"Nucleus, nucleoplasm; Cytoplasm","url":"https://www.uniprot.org/uniprotkb/Q66K89/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/E4F1","classification":"Common Essential","n_dependent_lines":589,"n_total_lines":1208,"dependency_fraction":0.48758278145695366},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/E4F1","total_profiled":1310},"omim":[{"mim_id":"605082","title":"RAS ASSOCIATION DOMAIN FAMILY PROTEIN 1; RASSF1","url":"https://www.omim.org/entry/605082"},{"mim_id":"603022","title":"E4F TRANSCRIPTION FACTOR 1; E4F1","url":"https://www.omim.org/entry/603022"},{"mim_id":"191170","title":"TUMOR PROTEIN p53; TP53","url":"https://www.omim.org/entry/191170"},{"mim_id":"164831","title":"BMI1 PROTOONCOGENE, POLYCOMB RING FINGER; BMI1","url":"https://www.omim.org/entry/164831"}],"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/E4F1"},"hgnc":{"alias_symbol":["E4F"],"prev_symbol":[]},"alphafold":{"accession":"Q66K89","domains":[{"cath_id":"3.30.160.60","chopping":"186-271","consensus_level":"medium","plddt":79.3426,"start":186,"end":271},{"cath_id":"-","chopping":"628-646_656-695_710-732","consensus_level":"high","plddt":62.7438,"start":628,"end":732}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q66K89","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q66K89-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q66K89-F1-predicted_aligned_error_v6.png","plddt_mean":52.38},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=E4F1","jax_strain_url":"https://www.jax.org/strain/search?query=E4F1"},"sequence":{"accession":"Q66K89","fasta_url":"https://rest.uniprot.org/uniprotkb/Q66K89.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q66K89/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q66K89"}},"corpus_meta":[{"pmid":"2956091","id":"PMC_2956091","title":"A cellular transcription factor E4F1 interacts with an E1a-inducible enhancer and mediates constitutive enhancer function in vitro.","date":"1987","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/2956091","citation_count":184,"is_preprint":false},{"pmid":"17110336","id":"PMC_17110336","title":"E4F1 is an atypical ubiquitin ligase that modulates p53 effector functions independently of degradation.","date":"2006","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/17110336","citation_count":181,"is_preprint":false},{"pmid":"2545525","id":"PMC_2545525","title":"DNA-binding activity of the adenovirus-induced E4F transcription factor is regulated by phosphorylation.","date":"1989","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/2545525","citation_count":100,"is_preprint":false},{"pmid":"35340126","id":"PMC_35340126","title":"m6A hypomethylation of DNMT3B regulated by ALKBH5 promotes intervertebral disc degeneration via E4F1 deficiency.","date":"2022","source":"Clinical and translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/35340126","citation_count":62,"is_preprint":false},{"pmid":"14729613","id":"PMC_14729613","title":"Identification of the E1A-regulated transcription factor p120 E4F as an interacting partner of the RASSF1A candidate tumor suppressor gene.","date":"2004","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/14729613","citation_count":62,"is_preprint":false},{"pmid":"15226446","id":"PMC_15226446","title":"The E4F protein is required for mitotic progression during embryonic cell cycles.","date":"2004","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/15226446","citation_count":49,"is_preprint":false},{"pmid":"16882984","id":"PMC_16882984","title":"E4F1: a novel candidate factor for mediating BMI1 function in primitive hematopoietic cells.","date":"2006","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/16882984","citation_count":47,"is_preprint":false},{"pmid":"2169022","id":"PMC_2169022","title":"E4F and ATF, two transcription factors that recognize the same site, can be distinguished both physically and functionally: a role for E4F in E1A trans activation.","date":"1990","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/2169022","citation_count":40,"is_preprint":false},{"pmid":"25843721","id":"PMC_25843721","title":"The transcription factor E4F1 coordinates CHK1-dependent checkpoint and mitochondrial functions.","date":"2015","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/25843721","citation_count":38,"is_preprint":false},{"pmid":"17557114","id":"PMC_17557114","title":"The role of LANP and ataxin 1 in E4F-mediated transcriptional repression.","date":"2007","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/17557114","citation_count":38,"is_preprint":false},{"pmid":"16652157","id":"PMC_16652157","title":"The LIM-only protein FHL2 is a negative regulator of E4F1.","date":"2006","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/16652157","citation_count":37,"is_preprint":false},{"pmid":"21088222","id":"PMC_21088222","title":"Transcription factor E4F1 is essential for epidermal stem cell maintenance and skin homeostasis.","date":"2010","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/21088222","citation_count":35,"is_preprint":false},{"pmid":"27621446","id":"PMC_27621446","title":"E4F1 controls a transcriptional program essential for pyruvate dehydrogenase activity.","date":"2016","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/27621446","citation_count":34,"is_preprint":false},{"pmid":"9121437","id":"PMC_9121437","title":"The adenovirus E1A-regulated transcription factor E4F is generated from the human homolog of nuclear factor phiAP3.","date":"1997","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/9121437","citation_count":33,"is_preprint":false},{"pmid":"33692124","id":"PMC_33692124","title":"Zinc finger protein E4F1 cooperates with PARP-1 and BRG1 to promote DNA double-strand break repair.","date":"2021","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/33692124","citation_count":31,"is_preprint":false},{"pmid":"1387083","id":"PMC_1387083","title":"The carboxy-terminal exon of the adenovirus E1A protein is required for E4F-dependent transcription activation.","date":"1992","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/1387083","citation_count":29,"is_preprint":false},{"pmid":"27621431","id":"PMC_27621431","title":"E4F1-mediated control of pyruvate dehydrogenase activity is essential for skin homeostasis.","date":"2016","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/27621431","citation_count":29,"is_preprint":false},{"pmid":"1831536","id":"PMC_1831536","title":"E1A-mediated activation of the adenovirus E4 promoter can occur independently of the cellular transcription factor E4F.","date":"1991","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/1831536","citation_count":22,"is_preprint":false},{"pmid":"21708927","id":"PMC_21708927","title":"E4F1 deficiency results in oxidative stress-mediated cell death of leukemic cells.","date":"2011","source":"The Journal of experimental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/21708927","citation_count":21,"is_preprint":false},{"pmid":"25843717","id":"PMC_25843717","title":"E4F1 is a master regulator of CHK1-mediated functions.","date":"2015","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/25843717","citation_count":21,"is_preprint":false},{"pmid":"34857760","id":"PMC_34857760","title":"The multifunctional protein E4F1 links P53 to lipid metabolism in adipocytes.","date":"2021","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/34857760","citation_count":16,"is_preprint":false},{"pmid":"31249647","id":"PMC_31249647","title":"MicroRNA-33-3p Regulates Vein Endothelial Cell Apoptosis in Selenium-Deficient Broilers by Targeting E4F1.","date":"2019","source":"Oxidative medicine and cellular longevity","url":"https://pubmed.ncbi.nlm.nih.gov/31249647","citation_count":16,"is_preprint":false},{"pmid":"32962114","id":"PMC_32962114","title":"E4 Transcription Factor 1 (E4F1) Regulates Sertoli Cell Proliferation and Fertility in Mice.","date":"2020","source":"Animals : an open access journal from MDPI","url":"https://pubmed.ncbi.nlm.nih.gov/32962114","citation_count":10,"is_preprint":false},{"pmid":"22024746","id":"PMC_22024746","title":"E4F1 dysfunction results in autophagic cell death in myeloid leukemic cells.","date":"2011","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/22024746","citation_count":10,"is_preprint":false},{"pmid":"24163401","id":"PMC_24163401","title":"Downregulation of transcription factor E4F1 in hepatocarcinoma cells: HBV-dependent effects on autophagy, proliferation and metabolism.","date":"2013","source":"Carcinogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/24163401","citation_count":10,"is_preprint":false},{"pmid":"26484288","id":"PMC_26484288","title":"Description of an optimized ChIP-seq analysis pipeline dedicated to genome wide identification of E4F1 binding sites in primary and transformed MEFs.","date":"2015","source":"Genomics data","url":"https://pubmed.ncbi.nlm.nih.gov/26484288","citation_count":10,"is_preprint":false},{"pmid":"37749649","id":"PMC_37749649","title":"Transcription factor E4F1 dictates spermatogonial stem cell fate decisions by regulating mitochondrial functions and cell cycle progression.","date":"2023","source":"Cell & bioscience","url":"https://pubmed.ncbi.nlm.nih.gov/37749649","citation_count":9,"is_preprint":false},{"pmid":"33618227","id":"PMC_33618227","title":"Angiotensin II promotes EMT of hepatocellular carcinoma cells through high mobility group protein B1 mediated by E4F1.","date":"2021","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/33618227","citation_count":8,"is_preprint":false},{"pmid":"30506647","id":"PMC_30506647","title":"E4F1 silencing inhibits the cell growth through cell-cycle arrest in malignant transformed cells induced by hydroquinone.","date":"2018","source":"Journal of biochemical and molecular toxicology","url":"https://pubmed.ncbi.nlm.nih.gov/30506647","citation_count":7,"is_preprint":false},{"pmid":"38742642","id":"PMC_38742642","title":"NF-κB factors cooperate with Su(Hw)/E4F1 to balance Drosophila/human immune responses via modulating dynamic expression of miR-210.","date":"2024","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/38742642","citation_count":7,"is_preprint":false},{"pmid":"37774036","id":"PMC_37774036","title":"Transcription factor E4F1 as a regulator of cell life and disease progression.","date":"2023","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/37774036","citation_count":6,"is_preprint":false},{"pmid":"36012478","id":"PMC_36012478","title":"Multi-Level Control of the ATM/ATR-CHK1 Axis by the Transcription Factor E4F1 in Triple-Negative Breast Cancer.","date":"2022","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/36012478","citation_count":5,"is_preprint":false},{"pmid":"37918959","id":"PMC_37918959","title":"E4F1 and ZNF148 are transcriptional activators of the -57A > C and wild-type TERT promoter.","date":"2023","source":"Genome research","url":"https://pubmed.ncbi.nlm.nih.gov/37918959","citation_count":3,"is_preprint":false},{"pmid":"39747033","id":"PMC_39747033","title":"E4F1 coordinates pyruvate metabolism and the activity of the elongator complex to ensure translation fidelity during brain development.","date":"2025","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/39747033","citation_count":1,"is_preprint":false},{"pmid":"32535047","id":"PMC_32535047","title":"Multiple domains in the 50 kDa form of E4F1 regulate promoter-specific repression and E1A trans-activation.","date":"2020","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/32535047","citation_count":0,"is_preprint":false},{"pmid":"41981464","id":"PMC_41981464","title":"The transcription factor E4F1 is crucial for spermatogonial differentiation and meiosis progression in mice.","date":"2026","source":"BMC genomics","url":"https://pubmed.ncbi.nlm.nih.gov/41981464","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":17557,"output_tokens":5392,"usd":0.066776},"stage2":{"model":"claude-opus-4-6","input_tokens":8949,"output_tokens":3426,"usd":0.195593},"total_usd":0.262369,"stage1_batch_id":"msgbatch_0118RScg3WGaGkaZRtWZbtce","stage2_batch_id":"msgbatch_01Cpfzvtbj42aqp5oYZ5Te2s","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1987,\n      \"finding\": \"E4F1 binds to two sites within the adenovirus E4 enhancer and one site directly upstream of the E4 TATA box, and this binding is required for constitutive transcriptional activity of the E4 promoter in vitro.\",\n      \"method\": \"In vitro transcription assay, DNA-binding assay, site-directed mutagenesis of binding sites\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro reconstitution with functional mutagenesis, foundational paper with 184 citations\",\n      \"pmids\": [\"2956091\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1989,\n      \"finding\": \"E4F DNA-binding activity is regulated by phosphorylation; alkaline phosphatase treatment abolishes E4F binding activity, and incubation of inactivated E4F with extract from virus-infected cells restores activity. E4F was purified as a single 50 kDa polypeptide.\",\n      \"method\": \"Affinity purification, alkaline phosphatase treatment, in vitro binding assay\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro biochemical reconstitution with phosphatase and extract rescue, 100 citations\",\n      \"pmids\": [\"2545525\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"E4F, but not ATF, confers E1A-dependent transcriptional inducibility to the E4 promoter; E4F forms a stable complex with E4 promoter DNA whereas ATF dissociates rapidly, and E4F activity (but not ATF) is markedly increased upon adenovirus infection.\",\n      \"method\": \"Cotransfection assay, DNA-binding competition assay, promoter mutagenesis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — functional promoter assays plus binding discrimination, replicated in subsequent studies\",\n      \"pmids\": [\"2169022\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1992,\n      \"finding\": \"E1A-mediated activation of the E4 promoter via E4F is dependent on the carboxy-terminal auxiliary regions (AR1 and AR2) of E1A; activation of E4F, but not ATF-2, requires these regions, placing E4F downstream of E1A CR3/AR elements.\",\n      \"method\": \"Transient transfection assay with E1A deletion mutants, DNA-binding assay\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic dissection via E1A mutagenesis with functional readout in single study\",\n      \"pmids\": [\"1387083\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"E4F is generated as a 50 kDa N-terminal fragment from the full-length 783-amino-acid E4F1 protein (human homolog of murine phiAP3), which contains a zinc finger domain; E1A(13S) differentially regulates the two forms via phosphorylation, stimulating DNA-binding of the 50 kDa fragment while reducing that of the full-length protein.\",\n      \"method\": \"Expression cloning, immunological characterization, phosphatase sensitivity assay, transient transfection\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — cDNA cloning with biochemical and functional validation, multiple orthogonal methods\",\n      \"pmids\": [\"9121437\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"E4F1 (p120 E4F) physically interacts with the tumor suppressor RASSF1A in yeast and mammalian cells, forming a complex in vivo; RASSF1A enhances G1 cell cycle arrest and S-phase inhibition induced by p120(E4F).\",\n      \"method\": \"Yeast two-hybrid, in vitro pull-down, co-immunoprecipitation, siRNA knockdown of RASSF1A, propidium iodide cell cycle analysis\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP plus in vitro pull-down and functional rescue with siRNA, single lab\",\n      \"pmids\": [\"14729613\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"E4F1 is required for mitotic progression during embryonic cell cycles; E4F knockout mice die at peri-implantation stage and E4F-/- blastocysts show chromosomal missegregation and increased apoptosis; E4F localizes to the mitotic spindle during M phase.\",\n      \"method\": \"Gene targeting (knockout mice), live-cell imaging/immunofluorescence of mitotic spindle localization, blastocyst culture\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with defined mitotic phenotype plus direct localization to spindle, multiple orthogonal readouts\",\n      \"pmids\": [\"15226446\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"E4F1 is an atypical E3 ubiquitin ligase for p53 that stimulates oligo-ubiquitylation of p53 in its hinge region on lysine residues distinct from those targeted by Hdm2; E4F1-dependent Ub-p53 conjugates are chromatin-associated and promote a p53-dependent transcriptional program leading to cell cycle arrest but not apoptosis. E4F1 and PCAF mediate mutually exclusive modifications at the same lysines.\",\n      \"method\": \"In vitro ubiquitylation assay, co-immunoprecipitation, chromatin fractionation, mutagenesis of p53 lysines, transcriptional reporter assays\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro reconstitution of E3 ligase activity plus mutagenesis plus chromatin association, multiple orthogonal methods, 181 citations\",\n      \"pmids\": [\"17110336\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"E4F1 interacts physically and genetically with BMI1 in hematopoietic cells; shRNA knockdown of E4f1 rescues the clonogenic and repopulating defects of Bmi1-/- hematopoietic cells independently of INK4A/ARF and p53.\",\n      \"method\": \"Co-immunoprecipitation, RNA interference knockdown, hematopoietic transplantation assay, colony assay\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — physical interaction confirmed plus genetic epistasis in transplantation rescue, multiple methods\",\n      \"pmids\": [\"16882984\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Full-length E4F1 (p120) but not its truncated form (p50) directly interacts with the LIM-only protein FHL2 in the nuclear compartment; FHL2 binding inhibits E4F1's capacity to repress transcription and block cell proliferation, and reduces nuclear E4F1-p53 complexes.\",\n      \"method\": \"In vitro pull-down, co-immunoprecipitation, transcriptional reporter assay, cell proliferation assay, subcellular fractionation\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vitro and in vivo binding plus functional transcriptional and proliferation readouts, single lab\",\n      \"pmids\": [\"16652157\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"E4F1 forms a complex with LANP (an INHAT corepressor) and modulates transcriptional repression; ataxin 1 relieves this repression by competing with E4F1 for LANP binding.\",\n      \"method\": \"Co-immunoprecipitation, transcriptional reporter assay, competition binding assay\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — Co-IP plus functional transcriptional assay, single lab\",\n      \"pmids\": [\"17557114\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"E4F1 is required for epidermal stem cell (ESC) maintenance and skin homeostasis; E4F1 conditional KO in basal keratinocytes depletes the ESC pool; clonogenic potential of E4F1 KO ESCs is rescued by Bmi1 overexpression or Ink4a/Arf or p53 depletion, placing E4F1 in the Bmi1-Arf-p53 pathway.\",\n      \"method\": \"Conditional knockout mouse, ex vivo clonogenic assay, genetic rescue by Bmi1 overexpression and Ink4a/Arf or p53 deletion\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — conditional KO with cell-autonomous phenotype and genetic epistasis rescue, multiple orthogonal approaches\",\n      \"pmids\": [\"21088222\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"E4F1 inactivation in myeloid leukemic cells causes mitochondrial defects, increased ROS production, and massive autophagic cell death, without affecting normal primary macrophages; this establishes E4F1 as essential for survival of transformed myeloid cells through mitochondrial function.\",\n      \"method\": \"Cre-mediated conditional E4F1 deletion in mouse leukemia model, ROS measurement, mitochondrial function assay, shRNA in human leukemic cell lines\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — in vivo genetic deletion plus in vitro mechanistic follow-up with ROS and mitochondrial assays, multiple cell types\",\n      \"pmids\": [\"21708927\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"E4F1 directly controls transcription of Chek1 (CHK1) and genes involved in mitochondrial function; E4F1 inactivation in p53-deficient transformed cells causes CHK1-dependent checkpoint deficiency, mitochondrial dysfunction, increased ROS, energy stress, inhibition of pyrimidine synthesis, and cell death.\",\n      \"method\": \"ChIP-seq, RNA-seq, conditional E4F1 KO, CHK1 functional assays, metabolic measurements (ROS, ATP, pyrimidine synthesis)\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — ChIP-seq identifies direct genomic targets, KO phenotype validated with multiple metabolic and signaling readouts\",\n      \"pmids\": [\"25843721\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"E4F1 physically interacts with and protects CHK1 protein from proteasomal degradation; E4f1-deficient hematopoietic cells accumulate DNA damage and show S-phase and mitotic defects that are fully rescued by ectopic Chek1 expression.\",\n      \"method\": \"Co-immunoprecipitation, conditional E4f1 KO, ectopic Chek1 rescue experiment, DNA damage markers, flow cytometry cell cycle analysis\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP plus genetic rescue by Chek1 re-expression, multiple orthogonal readouts\",\n      \"pmids\": [\"25843717\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"E4F1 transcriptionally controls four genes (Dlat, Dld, Mpc1, Slc25a19) involved in pyruvate oxidation; E4F1 loss results in ~80% decrease in pyruvate dehydrogenase (PDH) activity and altered pyruvate metabolism; muscle-specific E4F1 KO mice show low PDH activity, endurance defects, and lactic acidemia rescued by PDH stimulation or ketogenic diet.\",\n      \"method\": \"ChIP-seq, conditional muscle-specific KO mouse, PDH enzymatic activity assay, metabolic flux analysis, pharmacological rescue\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — ChIP-seq identifies direct targets, KO mouse with enzymatic activity measurement, pharmacological rescue validates mechanism\",\n      \"pmids\": [\"27621446\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"E4F1 transcriptionally regulates Dlat (E2 subunit of PDH complex) in keratinocytes; E4f1 KO keratinocytes show impaired PDH activity and redirection of glycolytic flux to lactate; shRNA depletion of Dlat recapitulates E4f1 KO defects including impaired clonogenic potential.\",\n      \"method\": \"Conditional KO keratinocytes, PDH activity assay, metabolic flux measurement, shRNA knockdown of Dlat, clonogenic assay\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — enzymatic activity assay plus genetic epistasis (Dlat shRNA phenocopy), multiple orthogonal methods\",\n      \"pmids\": [\"27621431\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"The p50E4F1 transcription regulatory region stably associates with E1A289R in vivo via E1A CR3; multiple cellular proteins including TBP bind the p50E4F1 TR region in vitro; trans-activation is promoter-specific and requires both E1A CR3 and N-terminal domains.\",\n      \"method\": \"Co-immunoprecipitation (in vivo), in vitro binding assay with TBP, GAL4-fusion transcriptional assays\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 — in vivo and in vitro binding combined with functional reporter assays, single lab\",\n      \"pmids\": [\"32535047\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"E4F1 is rapidly recruited to DNA double-strand breaks in a PARP-dependent manner, promotes ATR/CHK1 signaling and DNA-end resection, and facilitates homologous recombination; E4F1 binds the chromatin remodeler BRG1/SMARCA4 and together with PARP-1 mediates BRG1 recruitment to DNA lesions.\",\n      \"method\": \"Live-cell imaging of DSB recruitment, Co-immunoprecipitation of E4F1-BRG1-PARP-1, HR reporter assay, DNA resection assay, CHK1 signaling analysis\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (live imaging, Co-IP, functional HR assay), identifies molecular complex\",\n      \"pmids\": [\"33692124\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"E4F1 directly interacts with p53 and they are co-recruited to the Stearoyl-CoA Desaturase-1 (SCD1) locus in adipocytes to regulate monounsaturated fatty acid synthesis; E4F1 inactivation activates a p53-dependent transcriptional program for lipid metabolism.\",\n      \"method\": \"Co-immunoprecipitation, ChIP assay at SCD1 locus, conditional adipose E4F1 KO mouse, metabolic phenotyping, genetic rescue by p53 inactivation\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP plus ChIP at specific locus plus KO mouse with genetic rescue, multiple orthogonal methods\",\n      \"pmids\": [\"34857760\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"E4F1 binds the promoters of CHEK1, TTI2, and PPP5C in triple-negative breast cancer cells and regulates the entire ATM/ATR-CHK1 axis at multiple levels; E4F1 depletion strongly reduces CHK1, ATM, and ATR protein levels and signaling, sensitizing cells to gemcitabine and cisplatin.\",\n      \"method\": \"ChIP-seq, RNA-seq, shRNA knockdown, PDX ChIP validation, DNA damage response assays, drug sensitivity assays\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — ChIP-seq with in vivo PDX validation, functional signaling and drug response readouts, multiple orthogonal approaches\",\n      \"pmids\": [\"36012478\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"E4F1 binds specifically to the -57A>C mutant TERT promoter sequence and activates TERT transcription and telomerase activity; ZNF148 binds the wild-type TERT promoter at position 124 and also activates TERT.\",\n      \"method\": \"Proteomics-based DNA pulldown screen, ChIP assay, TERT reporter assay, telomerase activity assay\",\n      \"journal\": \"Genome research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — proteomics screen plus ChIP plus functional reporter and telomerase activity assays, single lab\",\n      \"pmids\": [\"37918959\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"E4F1 directly transcriptionally regulates both Dlat (PDC subunit) and Elp3 (Elongator complex subunit), coordinating AcCoA production by PDC with tRNA acetylation at wobble uridine 34 by Elongator; this coupling ensures translation fidelity and neuronal survival during brain development.\",\n      \"method\": \"Conditional KO mouse model, primary neuronal cells, ChIP assay at Dlat and Elp3 promoters, tRNA modification analysis, translation fidelity assay, PDH activity measurement\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — genetic KO plus direct ChIP at two target loci plus biochemical validation of tRNA modification and translation fidelity, multiple orthogonal methods\",\n      \"pmids\": [\"39747033\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"E4F1 is a multifunctional zinc-finger transcription factor and atypical E3 ubiquitin ligase that: (1) binds specific promoter elements to directly regulate transcription of genes controlling pyruvate dehydrogenase complex activity (Dlat, Dld, Mpc1, Slc25a19), CHK1-mediated checkpoint signaling (Chek1, TTI2, PPP5C), and Elongator-mediated tRNA acetylation (Elp3); (2) oligo-ubiquitylates p53 in its hinge region on lysines distinct from Hdm2 targets, promoting chromatin-associated Ub-p53 and cell cycle arrest rather than apoptosis; (3) interacts with and stabilizes CHK1 protein from degradation; (4) is recruited to DNA double-strand breaks in a PARP-dependent manner and facilitates homologous recombination by mediating BRG1/SMARCA4 chromatin remodeler recruitment; and (5) physically interacts with key regulators including BMI1, RASSF1A, FHL2, LANP, and p53 to coordinate cell proliferation, stem cell maintenance, and metabolic homeostasis.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"E4F1 is a zinc-finger transcription factor and atypical ubiquitin ligase that integrates metabolic homeostasis, DNA damage checkpoint signaling, chromatin remodeling, and stem cell maintenance. As a transcription factor, E4F1 directly binds promoters of genes controlling pyruvate dehydrogenase complex activity (Dlat, Dld, Mpc1, Slc25a19), the ATR/CHK1 checkpoint axis (Chek1, TTI2, PPP5C), and Elongator-mediated tRNA modification (Elp3), coupling acetyl-CoA production to translational fidelity during neuronal development [PMID:27621446, PMID:25843721, PMID:36012478, PMID:39747033]. E4F1 also functions as an atypical E3 ubiquitin ligase that oligo-ubiquitylates p53 on hinge-region lysines distinct from Hdm2 targets, generating chromatin-associated Ub-p53 species that selectively activate cell-cycle arrest rather than apoptosis [PMID:17110336]. Beyond transcription and ubiquitylation, E4F1 is recruited to DNA double-strand breaks in a PARP-dependent manner and facilitates homologous recombination by mediating BRG1/SMARCA4 chromatin-remodeler recruitment, while also physically stabilizing CHK1 protein against proteasomal degradation [PMID:33692124, PMID:25843717].\",\n  \"teleology\": [\n    {\n      \"year\": 1987,\n      \"claim\": \"Identification of E4F1 as a sequence-specific DNA-binding factor required for adenovirus E4 promoter transcription established its founding activity as a transcriptional regulator.\",\n      \"evidence\": \"In vitro transcription and DNA-binding assays with site-directed mutagenesis of E4 promoter elements\",\n      \"pmids\": [\"2956091\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cellular gene targets unknown\", \"No information on endogenous function\"]\n    },\n    {\n      \"year\": 1989,\n      \"claim\": \"Demonstration that E4F DNA-binding activity requires phosphorylation—abolished by phosphatase and restored by viral extract—revealed post-translational regulation as a key control mechanism.\",\n      \"evidence\": \"Alkaline phosphatase inactivation and rescue with adenovirus-infected cell extract; purification as 50 kDa polypeptide\",\n      \"pmids\": [\"2545525\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinase identity unknown\", \"Phosphorylation sites not mapped\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Cloning the full-length 783-residue E4F1 protein and showing that the 50 kDa form is an N-terminal cleavage product with distinct phosphorylation-dependent regulation resolved the molecular identity of the two E4F species.\",\n      \"evidence\": \"Expression cloning, immunological characterization, phosphatase sensitivity assays, transient transfection\",\n      \"pmids\": [\"9121437\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Protease responsible for p50 generation not identified\", \"Relative functions of p50 vs p120 in endogenous context unclear\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Discovery that E4F1 knockout mice die at peri-implantation with chromosomal missegregation and that E4F1 localizes to the mitotic spindle demonstrated an essential cell-autonomous role beyond transcription.\",\n      \"evidence\": \"Gene targeting in mice, live-cell imaging/immunofluorescence of spindle localization, blastocyst culture\",\n      \"pmids\": [\"15226446\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of spindle association unknown\", \"Whether mitotic role is direct or transcription-dependent not resolved\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Identification of E4F1 as an atypical E3 ubiquitin ligase that oligo-ubiquitylates p53 on hinge-region lysines, producing chromatin-associated Ub-p53 that drives cell-cycle arrest rather than apoptosis, revealed a second enzymatic activity distinct from its transcription factor function.\",\n      \"evidence\": \"In vitro ubiquitylation reconstitution, p53 lysine mutagenesis, chromatin fractionation, transcriptional reporter assays\",\n      \"pmids\": [\"17110336\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of E3 activity not determined\", \"Ubiquitin chain topology not fully characterized\", \"In vivo physiological importance of Ub-p53 pathway not genetically tested\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Physical and genetic interaction with BMI1 in hematopoietic cells—where E4F1 knockdown rescues Bmi1−/− stem cell defects independently of INK4A/ARF and p53—placed E4F1 in the polycomb pathway controlling stem cell self-renewal.\",\n      \"evidence\": \"Co-immunoprecipitation, shRNA knockdown, hematopoietic transplantation and colony assays in Bmi1−/− cells\",\n      \"pmids\": [\"16882984\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Nature of E4F1-BMI1 antagonism at chromatin level unresolved\", \"Direct transcriptional targets mediating rescue unknown\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Conditional knockout in basal keratinocytes showed E4F1 is required for epidermal stem cell maintenance and that its loss is rescued by Bmi1 overexpression or Ink4a/Arf/p53 deletion, extending the E4F1-BMI1-p53 axis to somatic stem cell compartments.\",\n      \"evidence\": \"Conditional KO mouse, ex vivo clonogenic assays, genetic rescue experiments\",\n      \"pmids\": [\"21088222\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether metabolic or checkpoint targets mediate the stem cell phenotype not dissected\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"ChIP-seq and functional studies revealed that E4F1 directly controls Chek1 transcription and physically stabilizes CHK1 protein from degradation, unifying its checkpoint and DNA damage roles through dual transcriptional and post-translational control of a single target.\",\n      \"evidence\": \"ChIP-seq, conditional KO, ectopic Chek1 rescue of hematopoietic phenotype, co-immunoprecipitation\",\n      \"pmids\": [\"25843721\", \"25843717\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which E4F1 prevents CHK1 proteasomal degradation not defined\", \"Whether E4F1 ubiquitylates CHK1 or acts as a scaffold not tested\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Identification of Dlat, Dld, Mpc1, and Slc25a19 as direct E4F1 targets established E4F1 as a master transcriptional regulator of pyruvate dehydrogenase complex activity and mitochondrial pyruvate oxidation, explaining the metabolic defects seen upon E4F1 loss.\",\n      \"evidence\": \"ChIP-seq, muscle-specific conditional KO, PDH enzymatic activity assays, metabolic flux analysis, pharmacological and dietary rescue\",\n      \"pmids\": [\"27621446\", \"27621431\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How E4F1 selectivity for metabolic vs checkpoint gene promoters is determined remains unclear\", \"No structural basis for promoter recognition\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Demonstration that E4F1 is recruited to DNA double-strand breaks in a PARP-dependent manner and mediates BRG1/SMARCA4 recruitment to promote homologous recombination revealed a direct chromatin-remodeling function at damage sites, beyond transcriptional checkpoint control.\",\n      \"evidence\": \"Live-cell DSB recruitment imaging, co-immunoprecipitation of E4F1-BRG1-PARP-1 complex, HR reporter and DNA resection assays\",\n      \"pmids\": [\"33692124\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the E3 ligase activity is required at DSBs is unknown\", \"Structural basis of PARP-dependent recruitment not resolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Co-recruitment of E4F1 and p53 to the SCD1 locus in adipocytes, with p53 inactivation rescuing E4F1-KO lipid metabolic phenotypes, demonstrated that E4F1-p53 cooperation extends beyond cell cycle to lipid metabolism regulation.\",\n      \"evidence\": \"Co-immunoprecipitation, ChIP at SCD1 locus, conditional adipose E4F1 KO mouse, genetic rescue by p53 deletion\",\n      \"pmids\": [\"34857760\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Ub-p53 or unmodified p53 mediates lipid transcription not distinguished\", \"Full set of lipid metabolism targets not mapped\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"ChIP-seq in triple-negative breast cancer revealed E4F1 occupancy at CHEK1, TTI2, and PPP5C promoters, showing that E4F1 controls the ATM/ATR-CHK1 axis at multiple nodes and that its depletion sensitizes cancer cells to genotoxic agents.\",\n      \"evidence\": \"ChIP-seq, RNA-seq, shRNA knockdown, PDX validation, drug sensitivity assays\",\n      \"pmids\": [\"36012478\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether E4F1 is a general vulnerability across cancer types not established\", \"Contribution of each individual target to chemosensitization not dissected\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Discovery that E4F1 coordinates acetyl-CoA production (via Dlat) with tRNA wobble uridine acetylation (via Elp3) linked its metabolic and translational roles, showing that E4F1 couples substrate supply to the Elongator tRNA modification pathway essential for neuronal survival.\",\n      \"evidence\": \"Conditional KO mouse, ChIP at Dlat and Elp3 promoters, tRNA modification and translation fidelity assays, PDH activity measurement\",\n      \"pmids\": [\"39747033\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether E4F1-Elongator coupling operates in non-neuronal tissues is untested\", \"Direct E4F1-Elongator physical interaction not demonstrated\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How E4F1 integrates its E3 ubiquitin ligase activity, transcriptional functions, and PARP-dependent DSB recruitment through a single protein—and whether these functions are cell-type-specifically partitioned—remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of E4F1 exists\", \"The protease generating the p50 form is unidentified\", \"Whether the E3 ligase domain is required for DSB repair or transcriptional functions is untested\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [0, 2, 13, 15, 16, 20, 22]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [7]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [0, 1, 4]},\n      {\"term_id\": \"GO:0016874\", \"supporting_discovery_ids\": [7]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [6, 9, 18]},\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [7, 18]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [0, 2, 13, 15, 20, 22]},\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [14, 18, 20]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [12, 15, 16, 19, 22]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [5, 6, 7, 14]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [6, 12]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [7]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"TP53\",\n      \"BMI1\",\n      \"CHEK1\",\n      \"SMARCA4\",\n      \"PARP1\",\n      \"RASSF1A\",\n      \"FHL2\",\n      \"LANP\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}