{"gene":"RTF1","run_date":"2026-06-10T07:46:28","timeline":{"discoveries":[{"year":1997,"finding":"RTF1 was identified as a nuclear protein whose mutation or deletion suppresses transcription start site alterations caused by a TBP specificity mutant, placing RTF1 as a regulator of TBP-dependent TATA site selection in vivo.","method":"Genetic suppressor screen, indirect immunofluorescence localization, transcription initiation analysis","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis combined with localization experiment, single lab, two orthogonal methods","pmids":["9234706"],"is_preprint":false},{"year":2000,"finding":"RTF1 functions as a transcription elongation factor, demonstrated by synthetic lethality with elongation factor genes (SPT4, SPT5, SPT16, PPR2, SRB5, CTK1, FCP1, POB3) and sensitivity to 6-azauracil and mycophenolic acid.","method":"Synthetic lethal screen, drug sensitivity assay (6-azauracil, mycophenolic acid), genetic epistasis","journal":"Genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with multiple elongation factors, drug sensitivity phenotypes, single lab","pmids":["11014804"],"is_preprint":false},{"year":2002,"finding":"Rtf1, Ctr9, and Leo1 are components of the Paf1-RNA Pol II complex, physically associating with Paf1, Cdc73, and Pol II but not with the Srb-mediator complex; deletion of RTF1 suppresses many paf1Δ phenotypes including reduced CLN1 expression.","method":"Tandem affinity purification, mass spectrometry, genetic analysis of double mutants","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — TAP-MS complex identification plus genetic epistasis, multiple orthogonal methods","pmids":["11884586"],"is_preprint":false},{"year":2003,"finding":"Rtf1 is required for global histone H2B ubiquitination at K123, and this is the indirect mechanism by which Rtf1 promotes H3-K4 and H3-K79 methylation; Rtf1 is also required for Set1 recruitment to active genes for H3-K4 methylation but not for H3-K36 methylation.","method":"Chromatin immunoprecipitation, histone modification analysis by western blot, genetic deletion analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple histone marks assayed, genetic epistasis with Rad6, replicated findings across multiple approaches","pmids":["12876293"],"is_preprint":false},{"year":2008,"finding":"The NMR structure of the human Rtf1 Plus3 domain reveals structural similarity to PAZ and Tudor domains; the Plus3 domain binds single-stranded DNA via basic residues on the rim of its beta sheet in vitro, but does not bind double-stranded DNA or RNA.","method":"NMR structure determination, in vitro DNA/RNA binding assay","journal":"Structure","confidence":"High","confidence_rationale":"Tier 1 / Moderate — NMR structure with functional binding validation, single lab but two orthogonal methods","pmids":["18184592"],"is_preprint":false},{"year":2008,"finding":"S. pombe Rtf1 (replication termination factor 1, a distinct protein from transcription factor Rtf1/Prf1) mediates site-specific replication termination at RTS1 via two myb/SANT DNA-binding domains and self-interaction through its C-terminal tail. NOTE: This paper describes the S. pombe replication termination Rtf1, which is a different protein from the transcription elongation Rtf1/Prf1 discussed in other papers.","method":"Domain characterization, DNA binding assays, genetic analysis with dominant-negative mutants","journal":"Genetics","confidence":"Low","confidence_rationale":"Tier 3 / Weak — this S. pombe Rtf1 is the replication termination factor, not the PAF1C-associated transcription factor; likely a symbol collision","pmids":["18723894"],"is_preprint":false},{"year":2011,"finding":"Single amino acid substitutions within the Rtf1 histone modification domain (HMD) abolish H2B ubiquitylation and impair H3 methylation, and also disrupt 3'-end formation of snoRNA transcripts, identifying H2B K123 ubiquitylation as required for noncoding RNA termination.","method":"Site-directed mutagenesis, histone modification assays, snoRNA 3'-end analysis, telomeric silencing and elongation assays","journal":"Genetics","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — mutagenesis of conserved residues with multiple phenotypic readouts, single lab but multiple orthogonal methods","pmids":["21441211"],"is_preprint":false},{"year":2012,"finding":"A 90-amino acid histone modification domain (HMD) within Rtf1 is sufficient to promote H3 K4 and K79 methylation and H2B K123 ubiquitylation independently of other Paf1C subunits when expressed as the only source of Rtf1; this function requires Rad6-Bre1 and conserved HMD residues important for chromatin association.","method":"Domain truncation and expression analysis, chromatin immunoprecipitation, histone modification western blot, DNA binding domain fusion experiments","journal":"PNAS","confidence":"High","confidence_rationale":"Tier 2 / Moderate — domain sufficiency demonstrated with multiple orthogonal approaches, cross-species HMD conservation tested","pmids":["22699496"],"is_preprint":false},{"year":2013,"finding":"A conserved domain of Rtf1 (Spt5-interacting domain) directly and physically interacts with the Spt5 C-terminal repeat domain (CTR), and this interaction is necessary and sufficient for tethering Paf1C to active chromatin; mutations disrupting this interaction or deletion of the Spt5 CTR release Paf1C from chromatin.","method":"In vitro binding assay, ChIP, genetic mutations, domain sufficiency experiments","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — direct interaction confirmed in vitro with in vivo ChIP validation and mutagenesis, single lab with multiple methods","pmids":["23775116"],"is_preprint":false},{"year":2013,"finding":"In S. pombe, Cdk9 phosphorylation of Spt5 creates a direct binding site for Prf1/Rtf1; Prf1 and the PAF complex are biochemically separable and exert opposing effects on the RNAPII elongation complex, with Prf1 negatively regulating elongation through H2B monoubiquitylation.","method":"Biochemical fractionation, genetic epistasis, phosphorylation-dependent binding assays","journal":"PLoS genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — phosphorylation-dependent interaction defined with biochemical separation and genetic analysis, single lab","pmids":["24385927"],"is_preprint":false},{"year":2015,"finding":"Human Rtf1 functions as a transcription elongation factor independently of the PAF1 complex; its Plus3 domain is critical for coactivator-dependent transcription activation in vitro; human Rtf1 and PAF1C regulate distinct gene subsets and PAF1C is recruited to genes independently of Rtf1 in human cells.","method":"In vitro transcription assay, RNA-seq, ChIP, mutational analysis","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro transcription with mutagenesis plus in vivo ChIP and RNA-seq, single lab","pmids":["26217014"],"is_preprint":false},{"year":2016,"finding":"The Rtf1 HMD directly interacts with the ubiquitin conjugase Rad6 and stimulates H2B monoubiquitylation independently of transcription; the crystal structure of the Rtf1 HMD was solved; site-specific in vivo crosslinking identified a conserved Rad6 interaction surface on the HMD; the HMD stimulates H2Bub in a transcription-free reconstituted in vitro system.","method":"Crystal structure determination, in vitro reconstitution, site-specific in vivo crosslinking, ChIP-exo, biochemical pulldown","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure, in vitro reconstitution, in vivo crosslinking, and ChIP-exo in one study with multiple orthogonal methods","pmids":["27840029"],"is_preprint":false},{"year":2020,"finding":"Cryo-EM structure of the complete Pol II elongation complex reveals RTF1 Plus3 domain associates with RPB12 and phosphorylated SPT5 CTR; RTF1 forms four α-helices extending along the Pol II protrusion and RPB10 to the polymerase funnel; a C-terminal 'fastener' helix retains PAF and a 'latch' reaches the bridge helix; RTF1 strongly stimulates Pol II elongation, requiring the latch, suggesting allosteric activation of translocation.","method":"Cryo-EM structure determination, in vitro transcription elongation assay, structure-function mutagenesis","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structure with functional elongation assay and mutagenesis of the latch, multiple orthogonal methods in one study","pmids":["32541898"],"is_preprint":false},{"year":2020,"finding":"In S. pombe, the Plus3 domain of Prf1/Rtf1 and phospho-Spt5 (pSpt5) function through parallel, distinct pathways to promote Prf1 function; the Plus3 domain has an alternate interface overlapping the pSpt5-binding site that can interact with single-stranded nucleic acid or PAF complex in vitro.","method":"Genetic epistasis, in vitro binding assay, domain mutational analysis","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis combined with in vitro binding, single lab, two methods","pmids":["32366382"],"is_preprint":false},{"year":2023,"finding":"The Rtf1 HMD interaction surface on Rad6 was mapped to the highly conserved N-terminal helix of Rad6; separation-of-function mutations disrupting the Rad6-HMD interface impair H2BK123 ubiquitylation but not other Rad6 functions; RNA-seq profiles of these mutants overlap extensively with those of H2B ubiquitylation-site mutants.","method":"In vitro crosslinking followed by mass spectrometry, genetic separation-of-function mutations, in vivo protein crosslinking, RNA-seq","journal":"PNAS","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — crosslinking-MS interaction mapping with in vivo crosslinking validation, separation-of-function genetics, and RNA-seq phenotypic confirmation, multiple orthogonal methods","pmids":["37216505"],"is_preprint":false},{"year":2023,"finding":"Rtf1 is essential for cardiogenesis in zebrafish and mammals; cardiac progenitors arrest in an immature state in rtf1 morphants/mutants; Rtf1's Plus3 domain (mediating Spt5 interaction) is required for cardiac progenitor formation; loss of Rtf1 reduces RNA Pol II occupancy at TSS of cardiac genes, reflecting reduced transcriptional pausing; pharmacological CDK9 inhibition restores cardiomyocyte formation in Rtf1-deficient embryos.","method":"Morpholino knockdown, genetic knockout (zebrafish and mouse), ChIP-seq, CDK9 inhibitor rescue experiments","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function in two model organisms with ChIP-seq and pharmacological rescue, preprint at time of initial reporting","pmids":["37873297"],"is_preprint":true},{"year":2026,"finding":"Rtf1 promotes promoter-proximal pausing of RNA Pol II; its Plus3 domain mediating Spt5 interaction is required for cardiogenic activity; in Rtf1-deficient zebrafish embryos RNA Pol II TSS occupancy is reduced relative to downstream occupancy, and CDK9 inhibition restores TSS occupancy and cardiomyocyte formation.","method":"Genetic knockout (zebrafish and mouse), ChIP-seq, CDK9 morpholino and pharmacological inhibition rescue, structure-function analysis","journal":"eLife","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function in two organisms with ChIP-seq and mechanistic rescue, peer-reviewed version of preprint","pmids":["41537425"],"is_preprint":false},{"year":2025,"finding":"An N-terminal region of Rtf1 directly interacts with the CHCT domain of Chd1 nucleosome remodeler; disruption of this interaction causes Chd1 accumulation at 5' gene ends, increased cryptic transcription, altered nucleosome positioning, and shifted histone modification profiles; a homologous region of mouse RTF1 also interacts with mouse CHD1 and CHD2 CHCT domains.","method":"Pull-down/co-IP interaction assays, domain mapping, mutagenesis, ChIP-seq, nucleosome positioning assays, cryptic transcription reporter","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — direct interaction demonstrated biochemically, multiple in vivo functional readouts, conservation confirmed in mouse, multiple orthogonal methods","pmids":["40867051"],"is_preprint":false},{"year":2025,"finding":"RTF1 physically interacts with CLOCK in Drosophila pacemaker neurons and promotes CLK occupancy at per and other clock gene promoters; SET1 forms a complex with CLK and RTF1 and increases H3K4me3 at per/tim promoters; human RTF1 physically interacts with BMAL1/CLOCK and affects circadian rhythms in U2OS cells.","method":"Co-immunoprecipitation, ChIP, H3K4me3 assays, genetic knockdown with behavioral rescue, overexpression rescue","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP with ChIP and functional rescue experiments, single lab","pmids":["41186576"],"is_preprint":false},{"year":2025,"finding":"RTF1 facilitates histone H2B monoubiquitination (H2Bub1) through its HMD domain to support Th17 cell differentiation; cells lacking the H2Bub1 E3 ligase subunit RNF40 (a known RTF1 physical interactor) similarly impair Th17 differentiation, while Treg differentiation is unaffected.","method":"Conditional knockout, histone modification western blot, T cell differentiation assays, genetic epistasis with RNF40","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional KO with defined cellular phenotype and epistasis with known RTF1 interactor RNF40, single lab","pmids":["40073106"],"is_preprint":false},{"year":2025,"finding":"RTF1 stimulates H2B-K120 ubiquitylation and H3K4me3 but RTF1 (unlike PAF1) does not contribute to transcription restart after DNA damage, dissociating RTF1's histone modification activity from the PAF1C-dependent transcription restoration function.","method":"Transcription recovery assay after UV damage, histone modification analysis, siRNA knockdown","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 / Weak — preprint, single lab, negative finding for RTF1's role in restart vs positive for histone modifications","pmids":["bio_10.1101_2025.07.23.666359"],"is_preprint":true}],"current_model":"RTF1 is a dissociable subunit of the PAF1 elongation complex that is recruited to active genes through its conserved Spt5-interacting domain binding phosphorylated Spt5 CTR; its histone modification domain (HMD) directly contacts the N-terminal helix of the ubiquitin conjugase Rad6 to stimulate cotranscriptional H2B monoubiquitylation (H2BK123/K120), which in turn drives H3K4 and H3K79 methylation; structurally, its Plus3 domain binds RPB12 and phospho-SPT5 while an extended helix-latch arrangement reaches the Pol II bridge helix to allosterically stimulate elongation; RTF1 also recruits the Chd1 nucleosome remodeler via a direct interaction with the Chd1 CHCT domain; and in vivo RTF1 promotes promoter-proximal RNA Pol II pausing required for proper cardiac gene expression and Th17 cell differentiation."},"narrative":{"mechanistic_narrative":"RTF1 is a dissociable transcription elongation factor of the PAF1 complex that couples RNA Polymerase II elongation to cotranscriptional histone modification at active genes [PMID:11884586, PMID:11014804]. It is recruited to transcribing chromatin through a conserved Spt5-interacting domain that directly binds the Cdk9-phosphorylated Spt5 C-terminal repeat domain, an interaction necessary and sufficient to tether PAF1C to active genes [PMID:23775116, PMID:24385927]. A discrete ~90-residue histone modification domain (HMD) is sufficient to drive cotranscriptional H2B monoubiquitylation (H2BK123/K120) and, indirectly, downstream H3K4 and H3K79 methylation, requiring Rad6-Bre1; the HMD contacts the conserved N-terminal helix of the ubiquitin conjugase Rad6 and stimulates H2Bub even in a transcription-free reconstituted system [PMID:12876293, PMID:22699496, PMID:27840029, PMID:37216505]. Structurally, the Plus3 domain associates with RPB12 and phospho-SPT5, while an extended helix arrangement with a C-terminal 'fastener' and a 'latch' reaching the Pol II bridge helix allosterically stimulates elongation [PMID:32541898, PMID:18184592]. RTF1 additionally recruits the Chd1 nucleosome remodeler through a direct N-terminal interaction with the Chd1 CHCT domain, restraining cryptic transcription and shaping nucleosome positioning [PMID:40867051]. In vivo RTF1 promotes promoter-proximal RNA Pol II pausing required for cardiac progenitor maturation and Th17 differentiation, with its histone-modifying and elongation roles supporting distinct gene-regulatory programs [PMID:41537425, PMID:40073106].","teleology":[{"year":1997,"claim":"Established RTF1 as a nuclear regulator of transcription start-site selection, the first functional placement of an otherwise uncharacterized gene.","evidence":"Genetic suppressor screen of a TBP specificity mutant with immunofluorescence localization in yeast","pmids":["9234706"],"confidence":"Medium","gaps":["No physical mechanism linking RTF1 to TBP or initiation defined","No interaction partners identified"]},{"year":2000,"claim":"Reframed RTF1 as a transcription elongation factor by genetically linking it to the elongation machinery.","evidence":"Synthetic lethality with elongation-factor genes and sensitivity to 6-azauracil/mycophenolic acid in yeast","pmids":["11014804"],"confidence":"Medium","gaps":["Genetic interactions do not show physical association","Molecular function during elongation unresolved"]},{"year":2002,"claim":"Defined RTF1 as a physical subunit of the Paf1-Pol II complex, providing the molecular assembly it acts within.","evidence":"Tandem affinity purification/mass spectrometry and double-mutant epistasis in yeast","pmids":["11884586"],"confidence":"High","gaps":["Stoichiometry and structural arrangement within PAF1C unknown","Recruitment mechanism to genes not addressed"]},{"year":2003,"claim":"Connected RTF1 to a chromatin output by showing it is required for H2B K123 ubiquitylation upstream of H3K4/H3K79 methylation.","evidence":"ChIP, histone-modification western blots, and deletion analysis in yeast","pmids":["12876293"],"confidence":"High","gaps":["Direct versus indirect role in ubiquitylation not distinguished","No structural basis for the activity"]},{"year":2008,"claim":"Provided the first structural view of an RTF1 module and a candidate nucleic-acid binding activity for the Plus3 domain.","evidence":"NMR structure of human Plus3 with in vitro DNA/RNA binding assays","pmids":["18184592"],"confidence":"High","gaps":["In vivo relevance of ssDNA binding unclear","Plus3 partners within the elongation complex not defined"]},{"year":2012,"claim":"Localized the histone-modification activity to a transferable 90-residue HMD that functions independently of other PAF1C subunits.","evidence":"Domain truncation/sufficiency, ChIP, histone-modification westerns, and DNA-binding fusion in yeast","pmids":["22699496","21441211"],"confidence":"High","gaps":["Direct enzymatic partner of the HMD not yet identified","Mechanism of HMD chromatin association incomplete"]},{"year":2013,"claim":"Identified the recruitment mechanism: a conserved RTF1 domain binds the phospho-Spt5 CTR to tether PAF1C to active chromatin.","evidence":"In vitro binding, ChIP, and mutagenesis in yeast; phospho-dependent binding via Cdk9 in S. pombe","pmids":["23775116","24385927"],"confidence":"High","gaps":["Species differences in PAF1C separability not reconciled","Coupling between recruitment and HMD activity not mechanistically linked"]},{"year":2015,"claim":"Demonstrated PAF1C-independent activities of human RTF1, separating its elongation/coactivator function from the complex.","evidence":"In vitro transcription, RNA-seq, ChIP, and mutational analysis in human cells","pmids":["26217014"],"confidence":"Medium","gaps":["Direct effectors of Plus3-dependent coactivation undefined","Gene-selectivity determinants unknown"]},{"year":2016,"claim":"Proved the HMD directly contacts Rad6 and stimulates H2Bub independently of transcription, establishing a direct enzymatic mechanism.","evidence":"Crystal structure of the HMD, transcription-free in vitro reconstitution, in vivo crosslinking, and ChIP-exo","pmids":["27840029"],"confidence":"High","gaps":["Precise Rad6 surface engaged not yet mapped at residue level (resolved later)","Regulation of HMD-Rad6 engagement in vivo unclear"]},{"year":2020,"claim":"Resolved how RTF1 engages the polymerase: the Plus3 domain binds RPB12/phospho-SPT5 and a latch reaches the bridge helix to allosterically stimulate elongation.","evidence":"Cryo-EM of the complete Pol II elongation complex with in vitro elongation assays and latch mutagenesis","pmids":["32541898","32366382"],"confidence":"High","gaps":["Coordination of allosteric elongation stimulation with H2Bub timing unknown","Conformational dynamics of the latch not captured"]},{"year":2023,"claim":"Mapped the HMD interface to the conserved Rad6 N-terminal helix and proved separation-of-function, isolating H2BK123ub from other Rad6 roles.","evidence":"Crosslinking-MS, in vivo crosslinking, separation-of-function genetics, and RNA-seq in yeast","pmids":["37216505"],"confidence":"High","gaps":["Whether this interface is conserved in metazoan RNF20/40 systems not addressed here","Quantitative contribution of HMD to genome-wide H2Bub not partitioned"]},{"year":2023,"claim":"Extended RTF1 function to organismal development, linking promoter-proximal pausing to cardiac progenitor maturation.","evidence":"Morpholino/knockout in zebrafish and mouse, ChIP-seq, and CDK9-inhibitor rescue (preprint)","pmids":["37873297"],"confidence":"Medium","gaps":["Mechanistic link between pausing and progenitor arrest incomplete","Target genes mediating the phenotype not fully defined"]},{"year":2025,"claim":"Identified a direct RTF1-Chd1 interaction that controls remodeler distribution, nucleosome positioning, and cryptic transcription.","evidence":"Co-IP/pulldown, domain mapping, ChIP-seq, nucleosome positioning, and cryptic-transcription reporters; conservation tested in mouse CHD1/CHD2","pmids":["40867051"],"confidence":"High","gaps":["How RTF1-Chd1 coordinates with HMD/elongation activities unresolved","In vivo dynamics of remodeler handoff not defined"]},{"year":2025,"claim":"Connected RTF1 HMD-driven H2Bub to immune cell fate and to circadian transcription, broadening its physiological reach.","evidence":"Conditional knockout with Th17/Treg differentiation assays and RNF40 epistasis; Co-IP, ChIP, and H3K4me3 with circadian behavior in Drosophila/U2OS cells","pmids":["40073106","41186576"],"confidence":"Medium","gaps":["Direct target genes driving Th17 and clock phenotypes not fully enumerated","Whether circadian role requires HMD versus elongation activity unclear"]},{"year":2026,"claim":"Consolidated the in vivo pausing model, showing the Plus3-Spt5 interaction underlies cardiogenic Pol II pausing rescued by CDK9 inhibition.","evidence":"Zebrafish/mouse knockout, ChIP-seq, CDK9 morpholino and pharmacological rescue, and structure-function analysis","pmids":["41537425"],"confidence":"Medium","gaps":["Causal chain from altered pausing to specific cardiac gene programs incomplete","Generality of pausing role across tissues not established"]},{"year":null,"claim":"How RTF1's distinct molecular activities — Spt5-dependent recruitment, allosteric elongation stimulation, HMD-driven H2Bub, and Chd1 recruitment — are integrated and differentially deployed across genes, tissues, and developmental programs remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified model partitioning RTF1's elongation versus chromatin activities by gene context","Determinants of gene-selective RTF1 dependence unknown","Metazoan structural basis for HMD-RNF20/40 engagement not directly resolved"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[1,2,10]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[8,11,17]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[11,12,14]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[4]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0]},{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[3,7,8]}],"pathway":[{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[2,12]},{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[3,11,17]}],"complexes":["PAF1 complex"],"partners":["SPT5","RAD6","BRE1","CHD1","RNF40","RPB12","CLOCK","BMAL1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q92541","full_name":"RNA polymerase-associated protein RTF1 homolog","aliases":[],"length_aa":710,"mass_kda":80.3,"function":"Component of the PAF1 complex (PAF1C) which has multiple functions during transcription by RNA polymerase II and is implicated in regulation of development and maintenance of embryonic stem cell pluripotency. PAF1C associates with RNA polymerase II through interaction with POLR2A CTD non-phosphorylated and 'Ser-2'- and 'Ser-5'-phosphorylated forms and is involved in transcriptional elongation, acting both independently and synergistically with TCEA1 and in cooperation with the DSIF complex and HTATSF1. PAF1C is required for transcription of Hox and Wnt target genes. PAF1C is involved in hematopoiesis and stimulates transcriptional activity of KMT2A/MLL1; it promotes leukemogenesis through association with KMT2A/MLL1-rearranged oncoproteins, such as KMT2A/MLL1-MLLT3/AF9 and KMT2A/MLL1-MLLT1/ENL. PAF1C is involved in histone modifications such as ubiquitination of histone H2B and methylation on histone H3 'Lys-4' (H3K4me3). PAF1C recruits the RNF20/40 E3 ubiquitin-protein ligase complex and the E2 enzyme UBE2A or UBE2B to chromatin which mediate monoubiquitination of 'Lys-120' of histone H2B (H2BK120ub1); UB2A/B-mediated H2B ubiquitination is proposed to be coupled to transcription. PAF1C is involved in mRNA 3' end formation probably through association with cleavage and poly(A) factors. In case of infection by influenza A strain H3N2, PAF1C associates with viral NS1 protein, thereby regulating gene transcription. Binds single-stranded DNA. Required for maximal induction of heat-shock genes. Required for the trimethylation of histone H3 'Lys-4' (H3K4me3) on genes involved in stem cell pluripotency; this function is synergistic with CXXC1 indicative for an involvement of a SET1 complex (By similarity)","subcellular_location":"Nucleus, nucleoplasm","url":"https://www.uniprot.org/uniprotkb/Q92541/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/RTF1","classification":"Common Essential","n_dependent_lines":1016,"n_total_lines":1208,"dependency_fraction":0.8410596026490066},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/RTF1","total_profiled":1310},"omim":[{"mim_id":"611633","title":"RTF1 HOMOLOG, PAF1/RNA POLYMERASE II COMPLEX COMPONENT; RTF1","url":"https://www.omim.org/entry/611633"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/RTF1"},"hgnc":{"alias_symbol":[],"prev_symbol":["KIAA0252"]},"alphafold":{"accession":"Q92541","domains":[{"cath_id":"3.90.70.200","chopping":"355-501","consensus_level":"high","plddt":92.2776,"start":355,"end":501},{"cath_id":"-","chopping":"508-572","consensus_level":"high","plddt":86.9497,"start":508,"end":572},{"cath_id":"1.20.5","chopping":"189-240","consensus_level":"high","plddt":85.614,"start":189,"end":240}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q92541","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q92541-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q92541-F1-predicted_aligned_error_v6.png","plddt_mean":67.0},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RTF1","jax_strain_url":"https://www.jax.org/strain/search?query=RTF1"},"sequence":{"accession":"Q92541","fasta_url":"https://rest.uniprot.org/uniprotkb/Q92541.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q92541/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q92541"}},"corpus_meta":[{"pmid":"12876293","id":"PMC_12876293","title":"The Rtf1 component of the Paf1 transcriptional elongation complex is required for ubiquitination of histone H2B.","date":"2003","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12876293","citation_count":237,"is_preprint":false},{"pmid":"11884586","id":"PMC_11884586","title":"Ctr9, Rtf1, and Leo1 are components of the Paf1/RNA polymerase II complex.","date":"2002","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/11884586","citation_count":206,"is_preprint":false},{"pmid":"32541898","id":"PMC_32541898","title":"Structure of complete Pol II-DSIF-PAF-SPT6 transcription complex reveals RTF1 allosteric activation.","date":"2020","source":"Nature structural & molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/32541898","citation_count":130,"is_preprint":false},{"pmid":"11014804","id":"PMC_11014804","title":"Synthetic lethal interactions suggest a role for the Saccharomyces cerevisiae Rtf1 protein in transcription elongation.","date":"2000","source":"Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/11014804","citation_count":110,"is_preprint":false},{"pmid":"27840029","id":"PMC_27840029","title":"The Histone Modification Domain of Paf1 Complex Subunit Rtf1 Directly Stimulates H2B Ubiquitylation through an Interaction with Rad6.","date":"2016","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/27840029","citation_count":90,"is_preprint":false},{"pmid":"9234706","id":"PMC_9234706","title":"Identification of RTF1, a novel gene important for TATA site selection by TATA box-binding protein in Saccharomyces cerevisiae.","date":"1997","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/9234706","citation_count":64,"is_preprint":false},{"pmid":"23775116","id":"PMC_23775116","title":"The recruitment of the Saccharomyces cerevisiae Paf1 complex to active genes requires a domain of Rtf1 that directly interacts with the Spt4-Spt5 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monoubiquitination and regulates morphogenesis and virulence in the meningitis-causing pathogen Cryptococcus neoformans.","date":"2025","source":"eLife","url":"https://pubmed.ncbi.nlm.nih.gov/40353352","citation_count":1,"is_preprint":false},{"pmid":"41186576","id":"PMC_41186576","title":"RTF1 enhances CLK occupancy and histone methylation at key circadian clock pacemaker gene loci.","date":"2025","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/41186576","citation_count":1,"is_preprint":false},{"pmid":"40073106","id":"PMC_40073106","title":"RTF1 mediates epigenetic control of Th17 cell differentiation via H2B monoubiquitination.","date":"2025","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/40073106","citation_count":1,"is_preprint":false},{"pmid":"38514187","id":"PMC_38514187","title":"The Rtf1/Prf1-dependent histone modification axis counteracts multi-drug resistance in fission 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transcription initiation analysis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis combined with localization experiment, single lab, two orthogonal methods\",\n      \"pmids\": [\"9234706\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"RTF1 functions as a transcription elongation factor, demonstrated by synthetic lethality with elongation factor genes (SPT4, SPT5, SPT16, PPR2, SRB5, CTK1, FCP1, POB3) and sensitivity to 6-azauracil and mycophenolic acid.\",\n      \"method\": \"Synthetic lethal screen, drug sensitivity assay (6-azauracil, mycophenolic acid), genetic epistasis\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with multiple elongation factors, drug sensitivity phenotypes, single lab\",\n      \"pmids\": [\"11014804\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Rtf1, Ctr9, and Leo1 are components of the Paf1-RNA Pol II complex, physically associating with Paf1, Cdc73, and Pol II but not with the Srb-mediator complex; deletion of RTF1 suppresses many paf1Δ phenotypes including reduced CLN1 expression.\",\n      \"method\": \"Tandem affinity purification, mass spectrometry, genetic analysis of double mutants\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — TAP-MS complex identification plus genetic epistasis, multiple orthogonal methods\",\n      \"pmids\": [\"11884586\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Rtf1 is required for global histone H2B ubiquitination at K123, and this is the indirect mechanism by which Rtf1 promotes H3-K4 and H3-K79 methylation; Rtf1 is also required for Set1 recruitment to active genes for H3-K4 methylation but not for H3-K36 methylation.\",\n      \"method\": \"Chromatin immunoprecipitation, histone modification analysis by western blot, genetic deletion analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple histone marks assayed, genetic epistasis with Rad6, replicated findings across multiple approaches\",\n      \"pmids\": [\"12876293\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"The NMR structure of the human Rtf1 Plus3 domain reveals structural similarity to PAZ and Tudor domains; the Plus3 domain binds single-stranded DNA via basic residues on the rim of its beta sheet in vitro, but does not bind double-stranded DNA or RNA.\",\n      \"method\": \"NMR structure determination, in vitro DNA/RNA binding assay\",\n      \"journal\": \"Structure\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — NMR structure with functional binding validation, single lab but two orthogonal methods\",\n      \"pmids\": [\"18184592\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"S. pombe Rtf1 (replication termination factor 1, a distinct protein from transcription factor Rtf1/Prf1) mediates site-specific replication termination at RTS1 via two myb/SANT DNA-binding domains and self-interaction through its C-terminal tail. NOTE: This paper describes the S. pombe replication termination Rtf1, which is a different protein from the transcription elongation Rtf1/Prf1 discussed in other papers.\",\n      \"method\": \"Domain characterization, DNA binding assays, genetic analysis with dominant-negative mutants\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — this S. pombe Rtf1 is the replication termination factor, not the PAF1C-associated transcription factor; likely a symbol collision\",\n      \"pmids\": [\"18723894\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Single amino acid substitutions within the Rtf1 histone modification domain (HMD) abolish H2B ubiquitylation and impair H3 methylation, and also disrupt 3'-end formation of snoRNA transcripts, identifying H2B K123 ubiquitylation as required for noncoding RNA termination.\",\n      \"method\": \"Site-directed mutagenesis, histone modification assays, snoRNA 3'-end analysis, telomeric silencing and elongation assays\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — mutagenesis of conserved residues with multiple phenotypic readouts, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"21441211\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"A 90-amino acid histone modification domain (HMD) within Rtf1 is sufficient to promote H3 K4 and K79 methylation and H2B K123 ubiquitylation independently of other Paf1C subunits when expressed as the only source of Rtf1; this function requires Rad6-Bre1 and conserved HMD residues important for chromatin association.\",\n      \"method\": \"Domain truncation and expression analysis, chromatin immunoprecipitation, histone modification western blot, DNA binding domain fusion experiments\",\n      \"journal\": \"PNAS\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — domain sufficiency demonstrated with multiple orthogonal approaches, cross-species HMD conservation tested\",\n      \"pmids\": [\"22699496\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"A conserved domain of Rtf1 (Spt5-interacting domain) directly and physically interacts with the Spt5 C-terminal repeat domain (CTR), and this interaction is necessary and sufficient for tethering Paf1C to active chromatin; mutations disrupting this interaction or deletion of the Spt5 CTR release Paf1C from chromatin.\",\n      \"method\": \"In vitro binding assay, ChIP, genetic mutations, domain sufficiency experiments\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — direct interaction confirmed in vitro with in vivo ChIP validation and mutagenesis, single lab with multiple methods\",\n      \"pmids\": [\"23775116\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"In S. pombe, Cdk9 phosphorylation of Spt5 creates a direct binding site for Prf1/Rtf1; Prf1 and the PAF complex are biochemically separable and exert opposing effects on the RNAPII elongation complex, with Prf1 negatively regulating elongation through H2B monoubiquitylation.\",\n      \"method\": \"Biochemical fractionation, genetic epistasis, phosphorylation-dependent binding assays\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — phosphorylation-dependent interaction defined with biochemical separation and genetic analysis, single lab\",\n      \"pmids\": [\"24385927\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Human Rtf1 functions as a transcription elongation factor independently of the PAF1 complex; its Plus3 domain is critical for coactivator-dependent transcription activation in vitro; human Rtf1 and PAF1C regulate distinct gene subsets and PAF1C is recruited to genes independently of Rtf1 in human cells.\",\n      \"method\": \"In vitro transcription assay, RNA-seq, ChIP, mutational analysis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro transcription with mutagenesis plus in vivo ChIP and RNA-seq, single lab\",\n      \"pmids\": [\"26217014\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"The Rtf1 HMD directly interacts with the ubiquitin conjugase Rad6 and stimulates H2B monoubiquitylation independently of transcription; the crystal structure of the Rtf1 HMD was solved; site-specific in vivo crosslinking identified a conserved Rad6 interaction surface on the HMD; the HMD stimulates H2Bub in a transcription-free reconstituted in vitro system.\",\n      \"method\": \"Crystal structure determination, in vitro reconstitution, site-specific in vivo crosslinking, ChIP-exo, biochemical pulldown\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure, in vitro reconstitution, in vivo crosslinking, and ChIP-exo in one study with multiple orthogonal methods\",\n      \"pmids\": [\"27840029\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Cryo-EM structure of the complete Pol II elongation complex reveals RTF1 Plus3 domain associates with RPB12 and phosphorylated SPT5 CTR; RTF1 forms four α-helices extending along the Pol II protrusion and RPB10 to the polymerase funnel; a C-terminal 'fastener' helix retains PAF and a 'latch' reaches the bridge helix; RTF1 strongly stimulates Pol II elongation, requiring the latch, suggesting allosteric activation of translocation.\",\n      \"method\": \"Cryo-EM structure determination, in vitro transcription elongation assay, structure-function mutagenesis\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structure with functional elongation assay and mutagenesis of the latch, multiple orthogonal methods in one study\",\n      \"pmids\": [\"32541898\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"In S. pombe, the Plus3 domain of Prf1/Rtf1 and phospho-Spt5 (pSpt5) function through parallel, distinct pathways to promote Prf1 function; the Plus3 domain has an alternate interface overlapping the pSpt5-binding site that can interact with single-stranded nucleic acid or PAF complex in vitro.\",\n      \"method\": \"Genetic epistasis, in vitro binding assay, domain mutational analysis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis combined with in vitro binding, single lab, two methods\",\n      \"pmids\": [\"32366382\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"The Rtf1 HMD interaction surface on Rad6 was mapped to the highly conserved N-terminal helix of Rad6; separation-of-function mutations disrupting the Rad6-HMD interface impair H2BK123 ubiquitylation but not other Rad6 functions; RNA-seq profiles of these mutants overlap extensively with those of H2B ubiquitylation-site mutants.\",\n      \"method\": \"In vitro crosslinking followed by mass spectrometry, genetic separation-of-function mutations, in vivo protein crosslinking, RNA-seq\",\n      \"journal\": \"PNAS\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — crosslinking-MS interaction mapping with in vivo crosslinking validation, separation-of-function genetics, and RNA-seq phenotypic confirmation, multiple orthogonal methods\",\n      \"pmids\": [\"37216505\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Rtf1 is essential for cardiogenesis in zebrafish and mammals; cardiac progenitors arrest in an immature state in rtf1 morphants/mutants; Rtf1's Plus3 domain (mediating Spt5 interaction) is required for cardiac progenitor formation; loss of Rtf1 reduces RNA Pol II occupancy at TSS of cardiac genes, reflecting reduced transcriptional pausing; pharmacological CDK9 inhibition restores cardiomyocyte formation in Rtf1-deficient embryos.\",\n      \"method\": \"Morpholino knockdown, genetic knockout (zebrafish and mouse), ChIP-seq, CDK9 inhibitor rescue experiments\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function in two model organisms with ChIP-seq and pharmacological rescue, preprint at time of initial reporting\",\n      \"pmids\": [\"37873297\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"Rtf1 promotes promoter-proximal pausing of RNA Pol II; its Plus3 domain mediating Spt5 interaction is required for cardiogenic activity; in Rtf1-deficient zebrafish embryos RNA Pol II TSS occupancy is reduced relative to downstream occupancy, and CDK9 inhibition restores TSS occupancy and cardiomyocyte formation.\",\n      \"method\": \"Genetic knockout (zebrafish and mouse), ChIP-seq, CDK9 morpholino and pharmacological inhibition rescue, structure-function analysis\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function in two organisms with ChIP-seq and mechanistic rescue, peer-reviewed version of preprint\",\n      \"pmids\": [\"41537425\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"An N-terminal region of Rtf1 directly interacts with the CHCT domain of Chd1 nucleosome remodeler; disruption of this interaction causes Chd1 accumulation at 5' gene ends, increased cryptic transcription, altered nucleosome positioning, and shifted histone modification profiles; a homologous region of mouse RTF1 also interacts with mouse CHD1 and CHD2 CHCT domains.\",\n      \"method\": \"Pull-down/co-IP interaction assays, domain mapping, mutagenesis, ChIP-seq, nucleosome positioning assays, cryptic transcription reporter\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — direct interaction demonstrated biochemically, multiple in vivo functional readouts, conservation confirmed in mouse, multiple orthogonal methods\",\n      \"pmids\": [\"40867051\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"RTF1 physically interacts with CLOCK in Drosophila pacemaker neurons and promotes CLK occupancy at per and other clock gene promoters; SET1 forms a complex with CLK and RTF1 and increases H3K4me3 at per/tim promoters; human RTF1 physically interacts with BMAL1/CLOCK and affects circadian rhythms in U2OS cells.\",\n      \"method\": \"Co-immunoprecipitation, ChIP, H3K4me3 assays, genetic knockdown with behavioral rescue, overexpression rescue\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP with ChIP and functional rescue experiments, single lab\",\n      \"pmids\": [\"41186576\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"RTF1 facilitates histone H2B monoubiquitination (H2Bub1) through its HMD domain to support Th17 cell differentiation; cells lacking the H2Bub1 E3 ligase subunit RNF40 (a known RTF1 physical interactor) similarly impair Th17 differentiation, while Treg differentiation is unaffected.\",\n      \"method\": \"Conditional knockout, histone modification western blot, T cell differentiation assays, genetic epistasis with RNF40\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional KO with defined cellular phenotype and epistasis with known RTF1 interactor RNF40, single lab\",\n      \"pmids\": [\"40073106\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"RTF1 stimulates H2B-K120 ubiquitylation and H3K4me3 but RTF1 (unlike PAF1) does not contribute to transcription restart after DNA damage, dissociating RTF1's histone modification activity from the PAF1C-dependent transcription restoration function.\",\n      \"method\": \"Transcription recovery assay after UV damage, histone modification analysis, siRNA knockdown\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — preprint, single lab, negative finding for RTF1's role in restart vs positive for histone modifications\",\n      \"pmids\": [\"bio_10.1101_2025.07.23.666359\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"RTF1 is a dissociable subunit of the PAF1 elongation complex that is recruited to active genes through its conserved Spt5-interacting domain binding phosphorylated Spt5 CTR; its histone modification domain (HMD) directly contacts the N-terminal helix of the ubiquitin conjugase Rad6 to stimulate cotranscriptional H2B monoubiquitylation (H2BK123/K120), which in turn drives H3K4 and H3K79 methylation; structurally, its Plus3 domain binds RPB12 and phospho-SPT5 while an extended helix-latch arrangement reaches the Pol II bridge helix to allosterically stimulate elongation; RTF1 also recruits the Chd1 nucleosome remodeler via a direct interaction with the Chd1 CHCT domain; and in vivo RTF1 promotes promoter-proximal RNA Pol II pausing required for proper cardiac gene expression and Th17 cell differentiation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RTF1 is a dissociable transcription elongation factor of the PAF1 complex that couples RNA Polymerase II elongation to cotranscriptional histone modification at active genes [#2, #1]. It is recruited to transcribing chromatin through a conserved Spt5-interacting domain that directly binds the Cdk9-phosphorylated Spt5 C-terminal repeat domain, an interaction necessary and sufficient to tether PAF1C to active genes [#8, #9]. A discrete ~90-residue histone modification domain (HMD) is sufficient to drive cotranscriptional H2B monoubiquitylation (H2BK123/K120) and, indirectly, downstream H3K4 and H3K79 methylation, requiring Rad6-Bre1; the HMD contacts the conserved N-terminal helix of the ubiquitin conjugase Rad6 and stimulates H2Bub even in a transcription-free reconstituted system [#3, #7, #11, #14]. Structurally, the Plus3 domain associates with RPB12 and phospho-SPT5, while an extended helix arrangement with a C-terminal 'fastener' and a 'latch' reaching the Pol II bridge helix allosterically stimulates elongation [#12, #4]. RTF1 additionally recruits the Chd1 nucleosome remodeler through a direct N-terminal interaction with the Chd1 CHCT domain, restraining cryptic transcription and shaping nucleosome positioning [#17]. In vivo RTF1 promotes promoter-proximal RNA Pol II pausing required for cardiac progenitor maturation and Th17 differentiation, with its histone-modifying and elongation roles supporting distinct gene-regulatory programs [#16, #19].\",\n  \"teleology\": [\n    {\n      \"year\": 1997,\n      \"claim\": \"Established RTF1 as a nuclear regulator of transcription start-site selection, the first functional placement of an otherwise uncharacterized gene.\",\n      \"evidence\": \"Genetic suppressor screen of a TBP specificity mutant with immunofluorescence localization in yeast\",\n      \"pmids\": [\"9234706\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No physical mechanism linking RTF1 to TBP or initiation defined\", \"No interaction partners identified\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Reframed RTF1 as a transcription elongation factor by genetically linking it to the elongation machinery.\",\n      \"evidence\": \"Synthetic lethality with elongation-factor genes and sensitivity to 6-azauracil/mycophenolic acid in yeast\",\n      \"pmids\": [\"11014804\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Genetic interactions do not show physical association\", \"Molecular function during elongation unresolved\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Defined RTF1 as a physical subunit of the Paf1-Pol II complex, providing the molecular assembly it acts within.\",\n      \"evidence\": \"Tandem affinity purification/mass spectrometry and double-mutant epistasis in yeast\",\n      \"pmids\": [\"11884586\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and structural arrangement within PAF1C unknown\", \"Recruitment mechanism to genes not addressed\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Connected RTF1 to a chromatin output by showing it is required for H2B K123 ubiquitylation upstream of H3K4/H3K79 methylation.\",\n      \"evidence\": \"ChIP, histone-modification western blots, and deletion analysis in yeast\",\n      \"pmids\": [\"12876293\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct versus indirect role in ubiquitylation not distinguished\", \"No structural basis for the activity\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Provided the first structural view of an RTF1 module and a candidate nucleic-acid binding activity for the Plus3 domain.\",\n      \"evidence\": \"NMR structure of human Plus3 with in vitro DNA/RNA binding assays\",\n      \"pmids\": [\"18184592\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo relevance of ssDNA binding unclear\", \"Plus3 partners within the elongation complex not defined\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Localized the histone-modification activity to a transferable 90-residue HMD that functions independently of other PAF1C subunits.\",\n      \"evidence\": \"Domain truncation/sufficiency, ChIP, histone-modification westerns, and DNA-binding fusion in yeast\",\n      \"pmids\": [\"22699496\", \"21441211\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct enzymatic partner of the HMD not yet identified\", \"Mechanism of HMD chromatin association incomplete\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identified the recruitment mechanism: a conserved RTF1 domain binds the phospho-Spt5 CTR to tether PAF1C to active chromatin.\",\n      \"evidence\": \"In vitro binding, ChIP, and mutagenesis in yeast; phospho-dependent binding via Cdk9 in S. pombe\",\n      \"pmids\": [\"23775116\", \"24385927\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Species differences in PAF1C separability not reconciled\", \"Coupling between recruitment and HMD activity not mechanistically linked\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Demonstrated PAF1C-independent activities of human RTF1, separating its elongation/coactivator function from the complex.\",\n      \"evidence\": \"In vitro transcription, RNA-seq, ChIP, and mutational analysis in human cells\",\n      \"pmids\": [\"26217014\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct effectors of Plus3-dependent coactivation undefined\", \"Gene-selectivity determinants unknown\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Proved the HMD directly contacts Rad6 and stimulates H2Bub independently of transcription, establishing a direct enzymatic mechanism.\",\n      \"evidence\": \"Crystal structure of the HMD, transcription-free in vitro reconstitution, in vivo crosslinking, and ChIP-exo\",\n      \"pmids\": [\"27840029\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Precise Rad6 surface engaged not yet mapped at residue level (resolved later)\", \"Regulation of HMD-Rad6 engagement in vivo unclear\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Resolved how RTF1 engages the polymerase: the Plus3 domain binds RPB12/phospho-SPT5 and a latch reaches the bridge helix to allosterically stimulate elongation.\",\n      \"evidence\": \"Cryo-EM of the complete Pol II elongation complex with in vitro elongation assays and latch mutagenesis\",\n      \"pmids\": [\"32541898\", \"32366382\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Coordination of allosteric elongation stimulation with H2Bub timing unknown\", \"Conformational dynamics of the latch not captured\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Mapped the HMD interface to the conserved Rad6 N-terminal helix and proved separation-of-function, isolating H2BK123ub from other Rad6 roles.\",\n      \"evidence\": \"Crosslinking-MS, in vivo crosslinking, separation-of-function genetics, and RNA-seq in yeast\",\n      \"pmids\": [\"37216505\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether this interface is conserved in metazoan RNF20/40 systems not addressed here\", \"Quantitative contribution of HMD to genome-wide H2Bub not partitioned\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended RTF1 function to organismal development, linking promoter-proximal pausing to cardiac progenitor maturation.\",\n      \"evidence\": \"Morpholino/knockout in zebrafish and mouse, ChIP-seq, and CDK9-inhibitor rescue (preprint)\",\n      \"pmids\": [\"37873297\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanistic link between pausing and progenitor arrest incomplete\", \"Target genes mediating the phenotype not fully defined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identified a direct RTF1-Chd1 interaction that controls remodeler distribution, nucleosome positioning, and cryptic transcription.\",\n      \"evidence\": \"Co-IP/pulldown, domain mapping, ChIP-seq, nucleosome positioning, and cryptic-transcription reporters; conservation tested in mouse CHD1/CHD2\",\n      \"pmids\": [\"40867051\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How RTF1-Chd1 coordinates with HMD/elongation activities unresolved\", \"In vivo dynamics of remodeler handoff not defined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Connected RTF1 HMD-driven H2Bub to immune cell fate and to circadian transcription, broadening its physiological reach.\",\n      \"evidence\": \"Conditional knockout with Th17/Treg differentiation assays and RNF40 epistasis; Co-IP, ChIP, and H3K4me3 with circadian behavior in Drosophila/U2OS cells\",\n      \"pmids\": [\"40073106\", \"41186576\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct target genes driving Th17 and clock phenotypes not fully enumerated\", \"Whether circadian role requires HMD versus elongation activity unclear\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Consolidated the in vivo pausing model, showing the Plus3-Spt5 interaction underlies cardiogenic Pol II pausing rescued by CDK9 inhibition.\",\n      \"evidence\": \"Zebrafish/mouse knockout, ChIP-seq, CDK9 morpholino and pharmacological rescue, and structure-function analysis\",\n      \"pmids\": [\"41537425\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Causal chain from altered pausing to specific cardiac gene programs incomplete\", \"Generality of pausing role across tissues not established\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How RTF1's distinct molecular activities — Spt5-dependent recruitment, allosteric elongation stimulation, HMD-driven H2Bub, and Chd1 recruitment — are integrated and differentially deployed across genes, tissues, and developmental programs remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model partitioning RTF1's elongation versus chromatin activities by gene context\", \"Determinants of gene-selective RTF1 dependence unknown\", \"Metazoan structural basis for HMD-RNF20/40 engagement not directly resolved\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [1, 2, 10]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [8, 11, 17]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [11, 12, 14]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [3, 7, 8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [2, 12]},\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [3, 11, 17]}\n    ],\n    \"complexes\": [\n      \"PAF1 complex\"\n    ],\n    \"partners\": [\n      \"SPT5\",\n      \"RAD6\",\n      \"BRE1\",\n      \"CHD1\",\n      \"RNF40\",\n      \"RPB12\",\n      \"CLOCK\",\n      \"BMAL1\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}