id: MODULE:rna_polymerase_i_transcription title: Human RNA polymerase I transcription of the rDNA — UBF and SL1 promoter recognition, RRN3-dependent recruitment of the 13-subunit Pol I, pre-rRNA synthesis, and TTF1/CAVIN1 (PTRF) termination and release description: >- RNA polymerase I (Pol I) transcribes a single class of gene, the tandemly repeated ribosomal DNA (rDNA), producing the 47S precursor rRNA that is processed into the 18S, 5.8S and 28S rRNAs. Transcription takes place in the nucleolus. The rDNA promoter is bipartite, with a core element around the transcription start site and an upstream control element. The HMG-box protein UBF binds and bends promoter and upstream DNA and activates transcription; the promoter-selectivity factor SL1, made of the TATA-box binding protein TBP and the Pol I-specific TBP-associated factors TAF1A, TAF1B, TAF1C and TAF1D (with TAF12), binds the core promoter and assembles with UBF into the preinitiation complex. RRN3 (TIF-IA) marks the initiation-competent subpopulation of Pol I and recruits it to the promoter by binding the SL1 subunits TAF1B and TAF1C. Pol I itself has 13 subunits in human: the two large catalytic subunits RPA1 (POLR1A) and RPA2 (POLR1B), the RPAC1 and RPAC2 subunits shared with Pol III (POLR1C, POLR1D), the five RPABC subunits shared with Pol II and Pol III (POLR2E, POLR2F, POLR2H, POLR2K, POLR2L), and the Pol I-specific RPA43 stalk (POLR1F), the TFIIF-like RPA49/RPA34 heterodimer (POLR1E, POLR1G) and the TFIIS-like RNA cleavage subunit RPA12 (POLR1H). Downstream of the transcribed region, the termination factor TTF1 binds the terminator repeats and pauses the elongating polymerase, and CAVIN1 (PTRF) binds the U-rich 3' end of the nascent pre-rRNA and releases the transcript and the polymerase. Pol I output is tuned by nutrient and stress signalling through RRN3, SL1, UBF and the RPA49 subunit. status: DRAFT scope: CONCRETE evidence: - source_id: PW:0000126 title: RNA polymerase I transcription pathway statement: >- The module boundary follows the RGD Pathway Ontology term and its diagram, which draws Ubtf with the SL1 complex, Rrn3 with SL1 and with RNA polymerase I, RNA polymerase I producing the pre-rRNA transcript, and Ptrf with Ttf1, together with elongation-associated factors (FACT, Paf1 complex, Supt4h1/Supt5h, Ncl) and regulators (Crebbp, Sirt1, Sirt7, mTOR, Erk and AMPK signalling). Derived through projects/RGD_PATHWAY_ONTOLOGY (pathways/PW_0000126.yaml). - source_id: GO:0006360 title: transcription by RNA polymerase I statement: >- The GO process mapped to PW:0000126 (skos:relatedMatch, from the PW definition cross-reference in projects/RGD_PATHWAY_ONTOLOGY/data/module_seeds.yaml). It is the module's process concept. - source_id: PMID:12498690 title: The cell cycle regulatory factor TAF1 stimulates ribosomal DNA transcription by binding to the activator UBF. statement: Human Pol I transcription requires UBF and SL1 assembled together on the promoter. supporting_text: In humans, Pol I transcription requires the upstream binding factor UBF and the selectivity factor SL1 to assemble coordinately on the promoter. - source_id: PMID:11250903 title: hRRN3 is essential in the SL1-mediated recruitment of RNA Polymerase I to rRNA gene promoters. statement: RRN3 links initiation-competent Pol I to promoter-bound SL1. supporting_text: We conclude that hRRN3 functions to recruit initiation-competent Pol I to rRNA gene promoters. - source_id: PMID:23150253 title: Basic mechanisms in RNA polymerase I transcription of the ribosomal RNA genes. statement: Review of the human Pol I transcription cycle used to set the step order of the module. supporting_text: Pol I-specific transcription factors guide Pol I to the rDNA promoter and contribute to multiple rounds of transcription initiation, promoter escape, elongation and termination. notes: >- Derived from the RGD Pathway Ontology diagram PW:0000126 (RNA polymerase I transcription pathway) through the RGD_PATHWAY_ONTOLOGY project's diagram->module route (seed in projects/RGD_PATHWAY_ONTOLOGY/data/module_seeds.yaml, tier related_module_only because the mapped GO term is shared with the fly module). RGD curates 37 human genes to PW:0000126: CAVIN1 CDC73 CREBBP CTR9 LEO1 NUCLEOLIN PAF1 POLR1A POLR1B POLR1C POLR1D POLR1E POLR1F POLR1G POLR1H POLR2E POLR2F POLR2H POLR2K POLR2L RRN3 RTF1 SIRT1 SIRT7 SKIC8 SSRP1 SUPT16H SUPT4H1 SUPT5H TAF12 TAF1A TAF1B TAF1C TAF1D TBP TTF1 UBTF. Twenty-three are modelled as participants (UBTF; the SL1 subunits TBP, TAF1A, TAF1B, TAF1C, TAF1D and TAF12; RRN3; the 13 Pol I subunits; TTF1 and CAVIN1). No gene outside the RGD list is added. Molecular functions were taken from each protein's experimental GO annotations in QuickGO (November 2026); only CAVIN1 has a gene review in this repository, and its core function (rRNA primary transcript binding) is used. One function is curator-authored without an experimental human GOA row: TTF1 transcription termination site sequence-specific DNA binding, from the recombinant-protein binding and termination assays of PMID:7597036. UBF has a further IDA row for RNA polymerase I general transcription initiation factor activity (PMID:12498690) that is not used, because the annoton is typed by the DNA element it recognises. UniProt labels are the current recommended names (UniProt REST, November 2026); POLR1D is P0DPB6, the reviewed entry for RPAC2 (P0DPB5 is the separate POLR1D isoform 2 entry). Boundary decisions. (1) The enzyme is one complex annoton with 13 active units, as in modules/dmel_nuclear_rna_polymerases.yaml (the Drosophila counterpart, which models Pol I, II and III as three complex annotons) and as for TFIIH in the NER module. Only RPA1 and RPA2 carry a function; the other subunits are units without a function because none has an experimental molecular function in human GOA that describes its role in the enzyme (POLR1G and POLR2H have only RNA- and ssDNA-binding rows, POLR2L a zinc-binding row). A family-of-subunits descriptor was rejected because the subunits are not paralogues but distinct obligate parts of one enzyme. (2) Shared subunits. The five RPABC subunits (POLR2E, POLR2F, POLR2H, POLR2K, POLR2L) and the two RPAC subunits (POLR1C, POLR1D) are listed in full in both this module and modules/rna_polymerase_iii_transcription.yaml, with the same accessions and roles, so that each enzyme is complete where it is modelled. No human RNA polymerase II module exists, and none is created here. (3) SL1 is one complex annoton. TAF12 is included as a unit without a function because RGD lists it and draws it in SL1; its experimental functions in GOA (transcription coactivator activity, contributes to RNA polymerase II general transcription initiation factor activity) concern its TFIID and SAGA roles. TBP is shared with TFIIIB in the Pol III module and with TFIID. (4) RRN3 is its own step rather than a unit of the Pol I complex: it binds only the initiation-competent subpopulation of the enzyme (Pol I beta) and is released after initiation. (5) Elongation is intrinsic to the enzyme in this module. The RGD diagram also draws FACT (SSRP1, SUPT16H), the PAF1 complex (PAF1, CTR9, LEO1, CDC73, RTF1, SKIC8), DSIF (SUPT4H1, SUPT5H) and nucleolin as positively affecting pre-rRNA synthesis. These are excluded: they are general chromatin and elongation factors shared with Pol II transcription (and FACT with replication and repair), and their Pol I roles rest mainly on yeast genetics and on effects on elongation rate rather than on a step the basal machinery cannot perform. They are candidates for an optional elongation-accessory part when a human Pol II elongation module exists to reference. (6) Termination is modelled with TTF1 and CAVIN1 (PTRF), both RGD genes drawn together on the diagram. The PTRF release activity was shown with the murine protein (PMID:9582279); the CAVIN1 gene review keeps the termination process and the rRNA primary transcript binding function while marking the human-specific IDA rows UNDECIDED, and the module follows the review. (7) Regulation is out of scope. CREBBP (acetylates RPA49), SIRT7 (deacetylates RPA49), SIRT1 (deacetylates TAF1B) and the mTOR, ERK, AMPK and p53 pathways drawn on the diagram (PW:0000180, PW:0000102, PW:0000542, PW:0000718) regulate Pol I output but do not perform a step of transcription; they are named here and in the description, not modelled. The same applies to the chromatin modification/remodeling pathway (PW:0001337), and to rRNA processing (PW:0001574) and ribosome biogenesis (PW:0001066), which are downstream. (8) Substrate versus participant: the rDNA template and the pre-rRNA product are not participants; CAVIN1 is a participant because its own transcript binding performs the release step. GO-CAM links. No production GO-CAM model in gocams/index.tsv contains RRN3, UBTF, the SL1 TAFs, TTF1, CAVIN1 or any Pol I subunit; TBP appears only in two Pol II models (ZNF76 regulation of TBP), which are not Pol I biology and are not linked. The seed's best_gocam, gomodel:617b481400000389 (KAT5 regulation of the cytoskeleton), overlaps only through SIRT1 and is unrelated, so no gocam_associations are recorded. PANTHER family ids and PTNs are deliberately not asserted. module: id: rna_polymerase_i_transcription label: Human RNA polymerase I transcription module_type: BIOLOGICAL_PROCESS concepts: - preferred_term: transcription by RNA polymerase I term: id: GO:0006360 label: transcription by RNA polymerase I description: The GO process mapped to PW:0000126. context: taxa: - preferred_term: Homo sapiens term: id: NCBITaxon:9606 label: Homo sapiens cellular_components: - preferred_term: nucleolus term: id: GO:0005730 label: nucleolus parts: - order: 1 role: promoter recognition and preinitiation complex assembly node: id: promoter_recognition label: rDNA promoter recognition by UBF and SL1 module_type: BIOLOGICAL_PROCESS description: >- UBF binds the upstream control element and the core promoter as a dimer and bends the DNA; SL1 binds the core element. The two factors bind cooperatively and form the platform that RRN3-bound Pol I docks onto. concepts: - preferred_term: RNA polymerase I preinitiation complex assembly term: id: GO:0001188 label: RNA polymerase I preinitiation complex assembly annotons: - id: ubf_promoter_binding label: UBF binds the rDNA upstream control element and core promoter participant: selector_type: GENE_PRODUCT gene_product: preferred_term: UBTF term: id: UniProtKB:P17480 label: Nucleolar transcription factor 1 function: preferred_term: RNA polymerase I cis-regulatory region sequence-specific DNA binding term: id: GO:0001165 label: RNA polymerase I cis-regulatory region sequence-specific DNA binding processes: - preferred_term: RNA polymerase I preinitiation complex assembly term: id: GO:0001188 label: RNA polymerase I preinitiation complex assembly locations: - preferred_term: nucleolus term: id: GO:0005730 label: nucleolus role_description: >- HMG-box architectural activator. Its experimental human molecular functions in GOA are RNA polymerase I cis-regulatory region and core promoter sequence-specific DNA binding (IDA, PMID:22368283) and RNA polymerase I general transcription initiation factor activity (IDA, PMID:12498690); the cis-regulatory binding term is used because it names the upstream control element that distinguishes UBF from SL1. evidence: - source_id: PMID:12498690 statement: UBF is an HMG-box factor that binds the rDNA promoter and activates Pol I transcription. supporting_text: UBF is an HMG box-containing factor that binds to the rDNA promoter and activates Pol I transcription through its acidic carboxy-terminal tail. - id: sl1_core_promoter_binding label: SL1 (TBP-TAF1A-TAF1B-TAF1C-TAF1D-TAF12) binds the core promoter and selects it for Pol I participant: selector_type: PROTEIN_COMPLEX protein_complex: preferred_term: SL1 (selectivity factor 1, TIF-IB) term: id: GO:0005668 label: RNA polymerase transcription factor SL1 complex active_units: - id: sl1_tbp label: TBP role: TATA-box binding protein, shared with TFIID and TFIIIB. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: TBP term: id: UniProtKB:P20226 label: TATA-box-binding protein function: preferred_term: RNA polymerase I core promoter sequence-specific DNA binding term: id: GO:0001164 label: RNA polymerase I core promoter sequence-specific DNA binding - id: sl1_taf1a label: TAF1A role: TAF(I)48; SL1 subunit, target of activating and inhibitory phosphorylation by nutrient and stress kinases. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: TAF1A term: id: UniProtKB:Q15573 label: TATA box-binding protein-associated factor RNA polymerase I subunit A - id: sl1_taf1b label: TAF1B role: TAF(I)63; TFIIB-like SL1 subunit that binds the core promoter and RRN3. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: TAF1B term: id: UniProtKB:Q53T94 label: TATA box-binding protein-associated factor RNA polymerase I subunit B function: preferred_term: RNA polymerase I core promoter sequence-specific DNA binding term: id: GO:0001164 label: RNA polymerase I core promoter sequence-specific DNA binding - id: sl1_taf1c label: TAF1C role: TAF(I)110; SL1 subunit that binds the core promoter and RRN3. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: TAF1C term: id: UniProtKB:Q15572 label: TATA box-binding protein-associated factor RNA polymerase I subunit C function: preferred_term: RNA polymerase I core promoter sequence-specific DNA binding term: id: GO:0001164 label: RNA polymerase I core promoter sequence-specific DNA binding - id: sl1_taf1d label: TAF1D role: TAF(I)41; SL1 subunit required for SL1 and Pol I occupancy of the rDNA promoter. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: TAF1D term: id: UniProtKB:Q9H5J8 label: TATA box-binding protein-associated factor RNA polymerase I subunit D - id: sl1_taf12 label: TAF12 role: TFIID and SAGA subunit also found in SL1. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: TAF12 term: id: UniProtKB:Q16514 label: Transcription initiation factor TFIID subunit 12 function: preferred_term: RNA polymerase I general transcription initiation factor activity term: id: GO:0001181 label: RNA polymerase I general transcription initiation factor activity processes: - preferred_term: RNA polymerase I preinitiation complex assembly term: id: GO:0001188 label: RNA polymerase I preinitiation complex assembly locations: - preferred_term: nucleolus term: id: GO:0005730 label: nucleolus role_description: >- The complex carries RNA polymerase I general transcription initiation factor activity, the IDA function of TAF1C (PMID:12498690); TBP, TAF1B and TAF1C each carry IDA rows for RNA polymerase I core promoter sequence-specific DNA binding (TBP, PMID:11250903; TAF1C, PMID:22368283; TAF1B, two further IDA papers). TAF1A, TAF1D and TAF12 have no experimental molecular function for this step and are units without a function. evidence: - source_id: PMID:17318177 statement: SL1 is an assembly of TBP and TAFs essential for Pol I preinitiation complex formation, and TAF1D is one of its subunits. supporting_text: SL1, an assembly of TBP and associated factors (TAFs), is essential for preinitiation complex formation at ribosomal RNA gene promoters in vitro. - source_id: PMID:17318177 statement: Loss of TAF1D removes SL1 and Pol I from the rDNA promoter. supporting_text: These data suggest that TAF(I)41 is integral to transcriptionally active SL1 - order: 2 role: recruitment of initiation-competent Pol I node: id: pol1_recruitment label: RRN3 (TIF-IA) recruits initiation-competent Pol I to SL1 module_type: BIOLOGICAL_PROCESS concepts: - preferred_term: transcription initiation at RNA polymerase I promoter term: id: GO:0006361 label: transcription initiation at RNA polymerase I promoter annotons: - id: rrn3_recruitment label: RRN3 bridges Pol I to the SL1 subunits TAF1B and TAF1C participant: selector_type: GENE_PRODUCT gene_product: preferred_term: RRN3 term: id: UniProtKB:Q9NYV6 label: RNA polymerase I-specific transcription initiation factor RRN3 function: preferred_term: RNA polymerase I general transcription initiation factor activity term: id: GO:0001181 label: RNA polymerase I general transcription initiation factor activity processes: - preferred_term: transcription initiation at RNA polymerase I promoter term: id: GO:0006361 label: transcription initiation at RNA polymerase I promoter locations: - preferred_term: nucleolus term: id: GO:0005730 label: nucleolus role_description: >- RRN3 binds the RPA43 stalk of Pol I and the TAF1B and TAF1C subunits of SL1, defining the Pol I beta subpopulation that can initiate. Its function is the IDA row RNA polymerase I general transcription initiation factor activity (PMID:11250903). It is the main point at which mTOR, ERK and AMPK signalling act on Pol I output. evidence: - source_id: PMID:11250903 statement: RRN3 contacts two SL1 subunits directly, and blocking this contact prevents Pol I recruitment. supporting_text: Human RRN3 interacts directly with TAF(I)110 and TAF(I)63 of promoter-selectivity factor SL1. Blocking this connection prevents recruitment of Pol I beta to the rDNA promoter. - source_id: PMID:34887565 statement: Cryo-EM of human Pol I bound to RRN3. supporting_text: the structure of human Pol I in complex with the initiation factor RRN3 at 3.1 Å resolution reveals stalk flipping upon RRN3 binding - order: 3 role: pre-rRNA synthesis node: id: pol1_transcription label: Pol I synthesises the 47S pre-rRNA module_type: PROTEIN_COMPLEX concepts: - preferred_term: transcription elongation by RNA polymerase I term: id: GO:0006362 label: transcription elongation by RNA polymerase I annotons: - id: pol1_enzyme label: RNA polymerase I (13 subunits) participant: selector_type: PROTEIN_COMPLEX protein_complex: preferred_term: RNA polymerase I term: id: GO:0005736 label: RNA polymerase I complex active_units: - id: pol1_polr1a label: POLR1A role: RPA1, largest catalytic subunit; forms the active centre and DNA cleft with RPA2. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR1A term: id: UniProtKB:O95602 label: DNA-directed RNA polymerase I subunit RPA1 function: preferred_term: DNA-directed RNA polymerase activity term: id: GO:0003899 label: DNA-directed RNA polymerase activity - id: pol1_polr1b label: POLR1B role: RPA2, second-largest catalytic subunit; forms the active centre with RPA1. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR1B term: id: UniProtKB:Q9H9Y6 label: DNA-directed RNA polymerase I subunit RPA2 function: preferred_term: DNA-directed RNA polymerase activity term: id: GO:0003899 label: DNA-directed RNA polymerase activity - id: pol1_rpac1_polr1c label: POLR1C role: RPAC1 (AC40), shared by Pol I and Pol III; forms the assembly platform with RPAC2 (alpha-like heterodimer). participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR1C term: id: UniProtKB:O15160 label: DNA-directed RNA polymerases I and III subunit RPAC1 - id: pol1_rpac2_polr1d label: POLR1D role: RPAC2 (AC19), shared by Pol I and Pol III; partner of RPAC1. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR1D term: id: UniProtKB:P0DPB6 label: DNA-directed RNA polymerases I and III subunit RPAC2 - id: pol1_rpabc1_polr2e label: POLR2E role: RPABC1, shared by Pol I, II and III; part of the lower jaw and core. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR2E term: id: UniProtKB:P19388 label: DNA-directed RNA polymerases I, II, and III subunit RPABC1 - id: pol1_rpabc2_polr2f label: POLR2F role: RPABC2, shared by Pol I, II and III; associates with the largest subunit. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR2F term: id: UniProtKB:P61218 label: DNA-directed RNA polymerases I, II, and III subunit RPABC2 - id: pol1_rpabc3_polr2h label: POLR2H role: RPABC3, shared by Pol I, II and III. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR2H term: id: UniProtKB:P52434 label: DNA-directed RNA polymerases I, II, and III subunit RPABC3 - id: pol1_rpabc4_polr2k label: POLR2K role: RPABC4, shared by Pol I, II and III; zinc-binding core subunit. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR2K term: id: UniProtKB:P53803 label: DNA-directed RNA polymerases I, II, and III subunit RPABC4 - id: pol1_rpabc5_polr2l label: POLR2L role: RPABC5, shared by Pol I, II and III; zinc-binding core subunit. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR2L term: id: UniProtKB:P62875 label: DNA-directed RNA polymerases I, II, and III subunit RPABC5 - id: pol1_polr1e label: POLR1E role: RPA49 (PAF53), with RPA34 the TFIIF/TFIIE-like heterodimer; needed for full activity and target of CBP acetylation and SIRT7 deacetylation. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR1E term: id: UniProtKB:Q9GZS1 label: DNA-directed RNA polymerase I subunit RPA49 - id: pol1_polr1g label: POLR1G role: RPA34 (PAF49, CAST), partner of RPA49 in the TFIIF-like heterodimer; interacts with UBF in activated transcription. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR1G term: id: UniProtKB:O15446 label: DNA-directed RNA polymerase I subunit RPA34 - id: pol1_polr1f label: POLR1F role: RPA43, the single-subunit Pol I stalk; contacts RRN3. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR1F term: id: UniProtKB:Q3B726 label: DNA-directed RNA polymerase I subunit RPA43 - id: pol1_polr1h label: POLR1H role: RPA12, TFIIS-like subunit that supports intrinsic RNA cleavage by the enzyme. participant: selector_type: GENE_PRODUCT gene_product: preferred_term: POLR1H term: id: UniProtKB:Q9P1U0 label: DNA-directed RNA polymerase I subunit RPA12 function: preferred_term: DNA-directed RNA polymerase activity term: id: GO:0003899 label: DNA-directed RNA polymerase activity processes: - preferred_term: nucleolar large rRNA transcription by RNA polymerase I term: id: GO:0042790 label: nucleolar large rRNA transcription by RNA polymerase I - preferred_term: transcription elongation by RNA polymerase I term: id: GO:0006362 label: transcription elongation by RNA polymerase I locations: - preferred_term: nucleolus term: id: GO:0005730 label: nucleolus role_description: >- One complex annoton with 13 active units, following the convention of modules/dmel_nuclear_rna_polymerases.yaml and the NER module's TFIIH. The two catalytic subunits carry DNA-directed RNA polymerase activity (IDA, PMID:34671025 and PMID:36271492; the EXP child 5'-3' RNA polymerase activity is also annotated). The shared RPAC and RPABC subunits and the Pol I-specific RPA49, RPA34, RPA43 and RPA12 are units without a GO function; their roles are given per unit. The seven shared subunits are listed with the same accessions in modules/rna_polymerase_iii_transcription.yaml. evidence: - source_id: PMID:34887565 statement: Human Pol I has 13 subunits, with a single-subunit stalk. supporting_text: Our structure confirms that human Pol I consists of 13 subunits with only one subunit forming the Pol I stalk. - source_id: PMID:34671025 statement: Seven of the ten core subunits are shared with Pol II and/or Pol III. supporting_text: Among the 10 core subunits of the hPol I, five subunits (RPABC1, RPABC2, RPABC3, RPABC4, and RPABC5) are shared by the three RNA polymerases (Pol I, II, and III) and two subunits (RPAC1 and RPAC2) are shared by Pol I and Pol III, indicating a highly conserved catalytic core - source_id: PMID:36271492 statement: Pol I-specific subunits carry TFIIF/TFIIE-like (RPA49/34) and TFIIS-like (RPA12) elements. supporting_text: In addition to TFIIF and TFIIE elements within the Pol I-specific subunits RPA49/34, TFIIS elements in subunit RPA12 and a DNA-mimicking element in RPA1, the integration of an HMG box element seems to contribute to the accumulating specialization. - order: 4 role: termination and release node: id: pol1_termination label: TTF1 pauses Pol I at the terminator and CAVIN1 (PTRF) releases the transcript and polymerase module_type: BIOLOGICAL_PROCESS concepts: - preferred_term: termination of RNA polymerase I transcription term: id: GO:0006363 label: termination of RNA polymerase I transcription annotons: - id: ttf1_terminator_binding label: TTF1 binds the rDNA terminator and pauses elongating Pol I participant: selector_type: GENE_PRODUCT gene_product: preferred_term: TTF1 term: id: UniProtKB:Q15361 label: Transcription termination factor 1 function: preferred_term: transcription termination site sequence-specific DNA binding term: id: GO:0001147 label: transcription termination site sequence-specific DNA binding processes: - preferred_term: termination of RNA polymerase I transcription term: id: GO:0006363 label: termination of RNA polymerase I transcription locations: - preferred_term: nucleolus term: id: GO:0005730 label: nucleolus role_description: >- Myb-domain protein that binds the terminator elements downstream of the transcribed region (T1 to T11 in human). The function is curator-authored: human TTF1 has no experimental molecular-function row in GOA, and the term is chosen from the recombinant human protein's terminator binding and termination activity reported in PMID:7597036. evidence: - source_id: PMID:7597036 statement: Recombinant human and mouse TTF-I bind the terminator in a species-specific way and terminate transcription. supporting_text: Recombinant TTF-I exhibits species-specific DNA binding and terminates transcription both in cell-free transcription assays and in transfection experiments. - id: cavin1_transcript_release label: CAVIN1 (PTRF) binds the 3' end of the pre-rRNA and releases Pol I and the transcript participant: selector_type: GENE_PRODUCT gene_product: preferred_term: CAVIN1 term: id: UniProtKB:Q6NZI2 label: Caveolae-associated protein 1 function: preferred_term: rRNA primary transcript binding term: id: GO:0042134 label: rRNA primary transcript binding processes: - preferred_term: termination of RNA polymerase I transcription term: id: GO:0006363 label: termination of RNA polymerase I transcription locations: - preferred_term: nucleolus term: id: GO:0005730 label: nucleolus role_description: >- The nuclear pool of CAVIN1 acts as the Pol I and transcript release factor. The function is the CAVIN1 gene review's second core function (rRNA primary transcript binding); the review records that the biochemistry was done with the murine protein. CAVIN1's main cellular role, in caveola coat assembly, is outside this module. evidence: - source_id: PMID:9582279 statement: PTRF dissociates paused Pol I ternary complexes, interacts with TTF-I and Pol I, and binds the 3' end of pre-rRNA. supporting_text: Consistent with its function in transcription termination, PTRF interacts with both TTF-I and Pol I. Moreover, we demonstrate specific binding of PTRF to transcripts containing the 3' end of pre-rRNA. connections: - source: ttf1_terminator_binding target: cavin1_transcript_release connection_type: PRECEDES description: TTF1-paused ternary complexes are the substrate for PTRF-mediated release. connections: - source: promoter_recognition target: pol1_recruitment connection_type: PRECEDES description: Promoter-bound SL1 is the docking site for RRN3-bound Pol I. - source: pol1_recruitment target: pol1_transcription connection_type: PRECEDES description: RRN3 is released after initiation and Pol I escapes the promoter and elongates. - source: pol1_transcription target: pol1_termination connection_type: PRECEDES description: Elongating Pol I reaches the terminator downstream of the 28S region.