Affinage

Showing POLR1H — RPA12 is a alias.

POLR1H

DNA-directed RNA polymerase I subunit RPA12 · UniProt Q9P1U0

Length
126 aa
Mass
13.9 kDa
Annotated
2026-06-10
44 papers in source corpus 29 papers cited in narrative 30 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 9/9 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

POLR1H (RPA12/A12.2) is an intrinsic subunit of the RNA polymerase I catalytic core that endows the enzyme with built-in 3'-RNA cleavage and proofreading activity, functioning as an internal counterpart of the Pol II elongation factor TFIIS (PMID:18160037, PMID:26929337). It is a two-zinc-binding subunit (PMID:1939219) organized into two functionally distinct domains. The C-terminal zinc-ribbon domain extends from the A190 jaw and inserts into the NTP entry pore to reach the active site, where it stimulates strong intrinsic RNA cleavage; deletion of this domain abolishes cleavage activity, and structures of human Pol I show this zinc ribbon entering an open funnel in the backtracked state to drive dinucleotide cleavage of mismatched DNA-RNA hybrids, establishing the proofreading mechanism (PMID:22396529, PMID:24153184, PMID:34671025, PMID:33737158). The N-terminal (Rpb9-like) domain does not stimulate cleavage but promotes backtracking and accurate nucleotide incorporation, and both domains are jointly required for faithful NTP addition, indicating that efficient backtracking and cleavage are prerequisites for proofreading (PMID:33737158, PMID:35341765). The C-terminal domain is conformationally dynamic: it is displaced from the active site as the cleft contracts during active elongation and repositioned during backtracking, with the A49-A34.5 heterodimer modulating its placement (PMID:27867008, PMID:27842382, PMID:30913026). Kinetically, A12.2 reshapes the nucleotide addition cycle by promoting pyrophosphate release and conferring an irreversible step per cycle (PMID:28846843, PMID:37355033), and it acts as an intrinsic destabilizer of the elongation complex that is required for proper transcription termination (PMID:29874602, PMID:33737158). In vivo, A12.2 is needed for elongation fidelity and termination at the rDNA, where backtracked-transcript cleavage releases torsional entrainment between polymerases and read-through occurs upon its loss (PMID:34946888, PMID:39999833), and it terminates transcription in part through direct interaction with the terminator-binding protein Reb1 (PMID:27035982). It also facilitates Pol I passage through nucleosomes (PMID:32060094) and contributes to assembly/stabilization of the largest catalytic subunit A190 (PMID:8417319). In human cells RPA12 localizes to the nucleolus and nucleoplasm, influences the basal expression and localization of the catalytic subunits RPA194 and RPA135 without being required for core complex integrity, and modulates cell proliferation and migration (PMID:33984768).

Mechanistic history

Synthesis pass · year-by-year structured walk · 26 steps
  1. 1991 Medium

    Established the basic biochemical character of A12.2 as a metal-binding Pol I subunit, defining a structural feature later shown to underlie its active-site function.

    Evidence 65Zn overlay (zinc-blotting) on purified yeast Pol I subunits

    PMID:1939219

    Open questions at the time
    • Number and arrangement of zinc sites not resolved
    • No functional consequence assigned to zinc binding at this stage
  2. 1993 High

    Identified RPA12 as the gene encoding A12.2 and linked it to assembly/stabilization of the largest Pol I subunit, framing an early structural role.

    Evidence Genetic complementation, peptide sequencing, deletion and multicopy suppressor assays in S. cerevisiae

    PMID:8417319

    Open questions at the time
    • Mechanism of A190 stabilization not defined
    • Catalytic contributions of A12.2 not yet known
  3. 1997 Medium

    Defined the genetic essentiality landscape of A12.2, showing it is conditionally required and acts collectively with A49/A34.5/A14 for rRNA synthesis.

    Evidence Gene deletion, synthetic lethality, and Pol II-promoter pre-rRNA rescue in yeast

    PMID:9121426

    Open questions at the time
    • Does not separate roles in initiation, elongation, or termination
    • Molecular basis of conditional essentiality unresolved
  4. 2001 Medium

    Confirmed functional conservation in fission yeast and provided early domain dissection assigning the N-terminal zinc finger as required and the C-terminal as dispensable for viability.

    Evidence Gene disruption, multicopy suppressor assay, and domain mutation in S. pombe

    PMID:11254133

    Open questions at the time
    • Apparent dispensability of CTD for growth contrasts with later catalytic findings
    • No in vitro biochemistry to resolve domain roles
  5. 2008 High

    Connected the structural location of A12.2 to enzymatic function, showing the C-terminal domain is required for the strong intrinsic RNA cleavage activity of Pol I.

    Evidence Cryo-EM of 14-subunit Pol I, crystal structure of subcomplex, and RNA cleavage assays

    PMID:18160037

    Open questions at the time
    • Resolution insufficient to define active-site geometry of the zinc ribbon
    • Mechanism of CTD entry into the active site not visualized
  6. 2012 High

    Established the architectural analogy to TFIIS by positioning the C-ribbon at the active site through the pore, explaining intrinsic cleavage.

    Evidence Lysine-lysine crosslinking-MS and homology modeling

    PMID:22396529

    Open questions at the time
    • Modeling-based positioning, not atomic structure
    • Dynamics of the ribbon not addressed
  7. 2013 High

    Provided atomic-resolution proof that the TFIIS-like zinc ribbon inserts into the NTP entry pore, giving a structural basis for cleavage and α-amanitin insensitivity.

    Evidence 3.0 Å X-ray crystal structure of 14-subunit yeast Pol I

    PMID:24153184

    Open questions at the time
    • Static structure does not capture elongation-state rearrangements
    • Catalytic mechanism of cleavage inferred from geometry
  8. 2016 High

    Resolved A12.2 as a dynamic element, showing its C-terminal domain is displaced from the active site during active elongation and repositioned by cleft contraction and A49-A34.5 contacts.

    Evidence Multiple cryo-EM structures of elongating and Rrn3-bound Pol I and cryo-electron tomography

    PMID:27418187 PMID:27842382 PMID:27867008

    Open questions at the time
    • Trigger for CTD repositioning during backtracking not fully defined
    • Initiation-complex resolution limited
  9. 2016 High

    Showed A12.2 protects Pol I from irreversible backtracking by slowing 1D diffusion and enabling cleavage of long transcripts, making external TFIIS unnecessary.

    Evidence Single-molecule optical tweezers with stochastic modeling

    PMID:26929337

    Open questions at the time
    • Does not separate N- and C-terminal domain contributions
    • In vivo relevance of long-transcript cleavage not tested
  10. 2016 High

    Identified direct protein-protein interaction between A12.2 and the terminator Reb1 as integral to Pol I termination.

    Evidence Crystal structure of Reb1-Ter, structure-guided mutagenesis, and termination assays in S. pombe

    PMID:27035982

    Open questions at the time
    • Whether the interaction couples cleavage to termination not mechanistically resolved
    • Conservation to human Pol I termination not tested here
  11. 2015 Medium

    Placed A12.2 in a regulatory pathway linking Ccr4-Not and mTORC1 signaling to Pol I elongation.

    Evidence Reciprocal Co-IP, genetic epistasis, and drug-sensitivity assays in yeast

    PMID:25815716

    Open questions at the time
    • Direct versus indirect repression of Ccr4-Not contacts unresolved
    • Single-lab genetic interaction
  12. 2016 Medium

    Reported a moonlighting role for A12.2 outside transcription, as a negative regulator of lipid metabolism via Msn4p sequestration.

    Evidence Co-IP, ChIP, deletion epistasis, and lipid measurements in yeast

    PMID:27637775

    Open questions at the time
    • Mechanistic link to Pol I function unclear
    • Not independently replicated
  13. 2016 Low

    Reported a conserved interaction between the initiation factor TIF-IA orthologue and RPA12 in a divergent protozoan.

    Evidence Co-IP, in vitro pull-down, and MS in Entamoeba histolytica

    PMID:26949087

    Open questions at the time
    • Single Co-IP/pulldown in divergent organism, not replicated
    • Functional consequence of interaction untested
    • Relevance to mammalian Pol I unknown
  14. 2017 High

    Quantified how A12.2 governs elementary catalytic steps, showing it profoundly alters the kinetics and energetics of nucleotide incorporation.

    Evidence Transient-state kinetics of ΔA12.2 versus wild-type Pol I

    PMID:28846843

    Open questions at the time
    • Specific chemical step affected not yet assigned
    • Domain-level resolution not addressed here
  15. 2018 High

    Defined A12.2 as an intrinsic destabilizer of the elongation complex, providing a mechanistic basis for its requirement in termination.

    Evidence In vitro EC dissociation kinetics and salt-dependence analysis

    PMID:29874602

    Open questions at the time
    • Link between EC destabilization and physiological termination not directly shown
    • Structural basis of altered electrostatics not defined
  16. 2019 High

    Showed reversible binding of A49-A34.5 controls A12.2 positioning and identified a novel CTD position at the A135 surface in nucleotide-bound elongation complexes.

    Evidence Near-atomic cryo-EM of elongation complexes with GMPCPP and biochemistry

    PMID:30913026

    Open questions at the time
    • Functional consequence of the A135-surface position not tested in vivo
    • Regulation of A49-A34.5 occupancy unresolved
  17. 2019 Medium

    Genetically implicated the jaw-lobe module including Rpa12 in regulating DNA insertion into the active cleft.

    Evidence Suppressor screen, in vivo rRNA analysis, ChIP, and tailed-template transcription in yeast

    PMID:31136569

    Open questions at the time
    • Rpa12 role inferred from suppressor mapping, not direct mutation
    • Mechanism of cleft regulation not isolated
  18. 2020 High

    Demonstrated a chromatin-transcription role, showing the Rpa12.2 C-terminal part supports processivity on naked DNA and through nucleosomes.

    Evidence In vitro transcription on naked and nucleosomal templates with defined Pol I mutants

    PMID:32060094

    Open questions at the time
    • In vivo contribution to nucleosome traversal not quantified
    • Coordination with A34.5/A49 not fully separated
  19. 2021 High

    Dissected domain-specific functions, assigning cleavage to the CTD and elongation/sequence-context effects and EC stabilization to the full subunit.

    Evidence Domain-deletion mutational analysis with cleavage, single-nucleotide addition, and EC stability assays

    PMID:33737158

    Open questions at the time
    • NTD mechanism in elongation not structurally explained
    • Interplay between domains during proofreading not yet integrated
  20. 2021 High

    Established the proofreading mechanism of human Pol I by visualizing the RPA12 zinc ribbon inserting into the funnel to cleave mismatched hybrid in the backtracked state.

    Evidence Cryo-EM of human Pol I in pre-translocation, post-translocation, and backtracked states

    PMID:34671025

    Open questions at the time
    • Cellular consequences of human proofreading not assessed structurally
    • Kinetics of human cleavage not measured here
  21. 2021 Medium

    Connected loss of A12.2 to genome-wide elongation infidelity and termination read-through in vivo, implicating Reb1 as a terminator.

    Evidence NET-seq in rpa12Δ S. cerevisiae

    PMID:34946888

    Open questions at the time
    • Causality between cleavage defect and read-through correlative
    • Single-lab genome-wide dataset
  22. 2021 Medium

    Characterized the human cellular role of RPA12, showing nucleolar/nucleoplasmic localization and opposing effects on proliferation and migration despite dispensability for core complex integrity.

    Evidence RNAi knockdown, Co-IP, chromatin fractionation, localization, proliferation and migration assays in HeLa/293T cells

    PMID:33984768

    Open questions at the time
    • Mechanism linking RPA12 loss to migration suppression unknown
    • Single-lab, two cell lines
  23. 2022 High

    Refined the domain logic of proofreading, showing CTD alone suffices for cleavage while both domains are required for faithful incorporation, establishing backtracking/cleavage as a prerequisite for fidelity.

    Evidence In vitro cleavage, backtracking, and fidelity assays with reconstituted mutant Pol I

    PMID:35341765

    Open questions at the time
    • Quantitative error-rate impact in vivo not measured
    • Structural intermediates of backtracking not captured
  24. 2023 Medium

    Showed RPA12 affects basal but not drug-inducible turnover of RPA194, distinguishing its role from BMH-21-mediated degradation in cancer cells.

    Evidence siRNA knockdown, BMH-21 treatment, IF, Co-IP, ChIP in human cancer cells

    PMID:37167337

    Open questions at the time
    • Mechanism of basal expression/localization control unresolved
    • Single-lab study
  25. 2023 High

    Assigned A12.2 a direct role in every nucleotide addition cycle by promoting pyrophosphate release, conferring an irreversible step.

    Evidence Transient-state kinetics of multi-nucleotide addition with PPi-dependence assays

    PMID:37355033

    Open questions at the time
    • Structural basis for PPi release acceleration not defined
    • Domain responsible for PPi effect not isolated
  26. 2025 Medium

    Integrated cleavage with termination physiology, showing Rpa12-mediated backtracked-transcript cleavage releases torsional entrainment between polymerases to facilitate termination at rDNA.

    Evidence In vitro cleavage assays, in vivo NET-seq/occupancy, and mathematical modeling

    PMID:39999833

    Open questions at the time
    • Direct measurement of torsional relief not provided
    • Generalization beyond rDNA untested

Open questions

Synthesis pass · forward-looking unresolved questions
  • How RPA12's biochemical activities (cleavage, PPi release, EC destabilization) translate into the human cellular phenotypes of altered RPA194/RPA135 expression, proliferation, and migration, and whether any disease association exists, remains unresolved.
  • No mechanistic link between catalytic roles and human proliferation/migration phenotypes
  • No disease-causing mutation characterized in the corpus
  • Human in vivo termination/fidelity consequences not directly tested

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140098 catalytic activity, acting on RNA 7 GO:0098772 molecular function regulator activity 4 GO:0003723 RNA binding 3 GO:0005198 structural molecule activity 2
Localization
GO:0005654 nucleoplasm 1 GO:0005730 nucleolus 1
Pathway
R-HSA-74160 Gene expression (Transcription) 4
Partners
A49-A34.5 HETERODIMERCCR4-NOTMSN4REB1RPA135RPA194RRN3
Complex memberships
RNA polymerase I

Evidence

Reading pass · 30 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1993 The RRN4/RPA12 gene encodes the A12.2 subunit of RNA polymerase I; deletion of RPA12 reduces the cellular concentration of A190 (the largest Pol I subunit), and overexpression of RPA190 partially suppresses the temperature-sensitive phenotype of rpa12 null mutants, indicating A12.2 plays a role in the assembly/stabilization of A190 into a functional Pol I structure. Genetic complementation, E. coli-expressed protein with specific antiserum, tryptic peptide sequencing, deletion analysis, multicopy suppressor assay Molecular and cellular biology High 8417319
1991 A12.2 is a zinc-binding subunit of yeast RNA polymerase I, identified by zinc-blotting (65Zn binding assay). Zinc-blotting technique (65Zn(II) overlay) on purified Pol I subunits The Journal of biological chemistry Medium 1939219
2007 Pol I has strong intrinsic 3'-RNA cleavage activity that requires the C-terminal domain of subunit A12.2; the cryo-EM structure places A12.2 within the 14-subunit Pol I complex, and the A49/34.5 heterodimer near the funnel acts as a built-in elongation factor. 12 Å cryo-EM structure, crystal structure of subcomplex A14/43, RNA cleavage assays Cell High 18160037
2012 Crosslinking-MS and structural modeling positioned A12.2 on the Pol I core such that the C-terminal zinc ribbon (C-ribbon) domain reaches the active site via the polymerase pore, analogous to the TFIIS C-ribbon in Pol II, explaining the strong intrinsic RNA cleavage activity of Pol I. Lysine-lysine crosslinking, mass spectrometry, homology modeling based on five crystal structures Nucleic acids research High 22396529
2013 The 3.0 Å crystal structure of 14-subunit yeast Pol I showed that A12.2 extends from the A190 jaw to the active site and inserts a TFIIS-like zinc ribbon into the NTP entry pore, providing a structural basis for A12.2's role in RNA cleavage and Pol I insensitivity to α-amanitin; the A49-A34.5 heterodimer contacts and potentially regulates A12.2 through extended arms. X-ray crystallography at 3.0 Å resolution Nature High 24153184
2016 Single-molecule optical tweezers experiments showed that A12.2 decreases the rate of 1D diffusion during backtracking and enables transcript cleavage up to 20 nt, protecting Pol I from nonrecoverable backtracking; unlike Pol II, Pol I does not require an external cleavage factor (TFIIS) because A12.2 fulfills this role as an intrinsic subunit. Single-molecule optical tweezers, stochastic theoretical modeling Proceedings of the National Academy of Sciences of the United States of America High 26929337
2016 Cryo-EM structures of elongating Pol I showed that during formation of the elongation complex the A12.2 C-terminal domain is displaced from the active site, revealing a conformational change associated with the transition from inactive to active polymerase states. Cryo-EM structures at 4.0 Å and 4.6 Å resolution of elongating Pol I Molecular cell High 27867008
2016 Cryo-EM structure of active transcribing Pol I at 3.8 Å resolution revealed a narrowed pore beneath the active site that no longer holds the RNA-cleavage-stimulating domain of subunit A12.2, consistent with A12.2 CTD displacement upon cleft contraction during active elongation. Single-particle cryo-EM at 3.8 Å and cryo-electron tomography at 29 Å Nature High 27842382
2016 Cryo-EM structure of the Pol I–Rrn3 initiation complex showed that in the Rrn3-bound (initiation-competent) monomeric Pol I, the A12.2 C-terminus is repositioned differently compared to dimeric Pol I, supporting a dual role for Rrn3 in stabilizing a monomeric form and influencing A12.2 active-site positioning. Cryo-EM structure at 7.5 Å resolution of the Pol I–Rrn3 complex Nature communications Medium 27418187
2017 Transient-state kinetics demonstrated that A12.2 profoundly affects the kinetics and energetics of elementary steps of Pol I-catalyzed nucleotide incorporation; a Pol I isoform lacking A12.2 shows dramatically altered incorporation kinetics compared to wild-type. Transient-state kinetic analysis (stopped-flow/quench-flow) of ΔA12.2 vs. wild-type Pol I Biochemistry High 28846843
2018 Using a novel EC dissociation kinetics assay, A12.2 was found to be an intrinsic destabilizer of the Pol I elongation complex; the salt-concentration dependence of Pol I EC dissociation indicates A12.2 alters electrostatic interactions within the EC, providing a mechanistic basis for A12.2's requirement in Pol I termination. In vitro elongation complex dissociation kinetics assay, salt-concentration dependence analysis Biophysical journal High 29874602
2019 Cryo-EM structures of Pol I elongation complexes revealed that most nucleotide-bound ECs lack the A49-A34.5 heterodimer and adopt a Pol II-like conformation in which the A12.2 C-terminal domain occupies a previously unobserved position at the A135 surface, suggesting that reversible binding of A49-A34.5 regulates A12.2 positioning and thereby modulates Pol I transcription initiation and elongation. Cryo-EM at 3.2–3.4 Å resolution of elongation complexes with nucleotide analog GMPCPP eLife High 30913026
2019 Genetic suppressor analysis showed that mutations in the jaw-lobe module interface (involving Rpa190 jaw, Rpa135 lobe, and Rpa12) act as extragenic suppressors of rpa49 deletion; the Rpa135-F301S suppressor mutant restores normal rRNA synthesis, increases Pol I density on rDNA, and generates a hyper-active Pol I in vitro tailed-template assay, indicating this region (including Rpa12) regulates DNA insertion into the active cleft. Spontaneous suppressor screen, in vivo rRNA synthesis analysis, ChIP, in vitro transcription tailed-template assay PLoS genetics Medium 31136569
2020 In vitro transcription assays with purified Pol I mutants showed that Pol I lacking the C-terminal part of Rpa12.2 has reduced processivity on naked DNA and further reduced ability to transcribe through nucleosomes, indicating that Rpa12.2 (together with the Rpa34.5/Rpa49 heterodimer) facilitates Pol I passage through nucleosomal barriers. In vitro transcription assays on naked and nucleosomal templates with purified wild-type and mutant Pol I variants The Journal of biological chemistry High 32060094
2021 Human Pol I cryo-EM structures in pre-translocation, post-translocation, and backtracked states showed that the C-terminal zinc ribbon of RPA12 inserts into an open funnel in the backtracked state and facilitates 'dinucleotide cleavage' on mismatched DNA-RNA hybrid, establishing the proofreading mechanism of human Pol I. Cryo-EM structures of human Pol I in multiple states at near-atomic resolution Cell discovery High 34671025
2021 Mutational analysis of A12.2 domain contributions showed: (1) deletion of the C-terminal domain (ΔA12CTD) abolishes RNA cleavage activity; (2) ΔA12CTD Pol I is slightly faster than WT in single-nucleotide addition; (3) the N-terminal domain of A12 does not stimulate intrinsic RNA cleavage but contributes to core elongation properties, including sensitivity to downstream AT-rich sequence context; (4) removal of the entire A12 subunit (not just the CTD) stabilizes elongation complexes. Mutational analysis (domain deletions), single-nucleotide addition kinetics, RNA cleavage assays, elongation complex stability assays Biophysical journal High 33737158
2021 NET-seq of rpa12Δ yeast showed template-sequence-specific changes in Pol I occupancy throughout the 35S gene, read-through of both known termination sites and into the IGS including the 5S gene, and increased occupancy upstream of a Reb1 binding site with sharp drop downstream, implicating Reb1 as a third terminator and demonstrating A12.2's essential role in elongation fidelity and termination in vivo. Native elongating transcript sequencing (NET-seq) in rpa12Δ S. cerevisiae Genes Medium 34946888
2021 RPA12 knockdown in human HeLa and 293T cells alters the expression and localization of Pol I subunits RPA194 and RPA135, but the core Pol I complex between RPA194 and RPA135 remains intact, and transcription of Pol I and its chromatin engagement are unaffected, indicating RPA12 affects basal expression of RPA194 but is not required for core complex integrity or chromatin engagement. RNAi knockdown, co-immunoprecipitation, chromatin fractionation, RT-qPCR in human cancer cells Biochemical and biophysical research communications Medium 33984768
2021 RPA12 localizes to the nucleolus and nucleoplasm in HeLa cells; knockdown reduces Pol I-mediated transcription and inhibits proliferation of 293T and HeLa cells, while unexpectedly suppressing HeLa cell migration, demonstrating opposing roles in proliferation and migration. Subcellular fractionation/immunofluorescence, RNAi knockdown, cell proliferation assays, cell migration assays Biochemical and biophysical research communications Medium 33984768
2022 In vitro studies with Pol I mutants showed that (1) the intact C-terminal domain of Rpa12.2 is sufficient for the RNA cleavage reaction; (2) the N-terminal domains of both Rpa12.2 and the Rpa34.5/49 heterodimer facilitate backtracking and RNA cleavage; (3) both N- and C-terminal domains of Rpa12.2 are required for faithful NTP incorporation, suggesting that efficient backtracking/cleavage is a prerequisite for proofreading. In vitro RNA cleavage assays, backtracking assays, transcription fidelity assays with reconstituted mutant Pol I enzymes The Journal of biological chemistry High 35341765
2023 RPA12 silencing in human cancer cells causes alterations in expression and localization of Pol I subunits RPA194 and RPA135; the BMH-21-mediated degradation of RPA194 is independent of RPA12, indicating RPA12 affects basal expression but not drug-inducible turnover of the catalytic subunit. siRNA knockdown, small-molecule inhibitor treatment (BMH-21), immunofluorescence, co-immunoprecipitation, chromatin immunoprecipitation PloS one Medium 37167337
2023 Transient-state kinetics of multi-nucleotide addition demonstrated that A12.2 contributes to every repeating cycle of nucleotide addition; ΔA12 Pol I exhibits a fundamentally different kinetic mechanism requiring a reversible step (slow PPi release/pyrophosphorolysis), whereas wild-type Pol I has an irreversible step per cycle, indicating A12.2 promotes PPi release from the active site. Transient-state kinetics of multi-nucleotide addition, pyrophosphate concentration-dependence assays Journal of molecular biology High 37355033
1997 Genetic analysis in S. cerevisiae showed that A12.2 is nonessential at 30°C but essential at extreme temperatures; triple mutants lacking A34.5, A49, and A12.2 are viable, but inactivating A12.2 together with A14 is lethal, and this lethality is rescued by expressing pre-rRNA from a Pol II promoter, demonstrating that these subunits are collectively essential for rRNA synthesis. Gene deletion analysis, synthetic lethality tests, Pol II-promoter-driven pre-rRNA rescue experiment Molecular and cellular biology Medium 9121426
2016 In S. pombe, protein-protein interactions between the transcription termination domain (TTD) of Reb1 and the Rpa12 subunit of RNA Pol I are an integral part of the transcription termination mechanism; double mutations in TTD that abolished interaction with Rpa12 greatly reduced transcription termination. Crystal structure of Reb1-Ter complex, structure-guided mutagenesis, protein-protein interaction assays, transcription termination assays Proceedings of the National Academy of Sciences of the United States of America High 27035982
2016 Rpa12p interacts with the stress-responsive transcription factor Msn4p and prevents its binding to the AYR1 promoter; deletion of RPA12 leads to triacylglycerol accumulation due to unrestrained Msn4p-driven AYR1 transcription, revealing a role for Rpa12p as a negative regulator of lipid metabolism. Co-immunoprecipitation, chromatin immunoprecipitation, deletion analysis, lipid measurements, double deletion epistasis FEBS letters Medium 27637775
2001 Disruption of S. pombe Sprpa12+ causes temperature-sensitive growth; overexpression of Sprpa190+/nuc1+ partially suppresses the growth defect, mirroring S. cerevisiae findings and confirming functional conservation; mutant analysis revealed that the N-terminal zinc-finger domain is required for function but the C-terminal zinc-finger domain is dispensable. Gene disruption, multicopy suppressor assay, domain deletion/mutation analysis in S. pombe Molecular & general genetics Medium 11254133
2007 Phosphorylation analysis identified 13 phosphoserine/phosphothreonine residues in yeast Pol I distributed across 5 subunits; systematic mutation of individual phosphosites showed they are non-essential, but one mutation in A190 (S685D) was synthetically lethal with rpa12Δ, suggesting a functional link between A190 phosphorylation and A12.2 in RNA cleavage/elongation or termination. Mass spectrometry phosphoproteomics, systematic site-directed mutagenesis, synthetic lethality analysis Nucleic acids research Medium 18084032
2015 The A12.2 and A14 subunits repress Ccr4-Not interactions with Pol I; ccr4Δ rpa12Δ double mutants show enhanced sensitivity to transcription elongation inhibition, and the double mutant rescues the growth defect of ccr4Δ on mTORC1 inhibitors, placing A12.2 in a pathway where Ccr4-Not promotes Pol I elongation downstream of mTORC1 signaling. Co-immunoprecipitation, genetic interaction analysis, drug sensitivity assays, deletion epistasis PLoS genetics Medium 25815716
2016 In E. histolytica, the TIF-IA orthologue (EhTIF-IA) interacts with the RNA Pol I-specific subunit RPA12 both in vivo (co-immunoprecipitation) and in vitro (pull-down), and mass spectrometry confirmed RPA12 among the interacting partners, indicating a conserved interaction between the TIF-IA initiation factor and RPA12. Co-immunoprecipitation in vivo, in vitro pull-down, mass spectrometry Journal of biosciences Low 26949087
2025 In vitro and in vivo experiments showed that Rpa12-mediated backtracked transcript cleavage facilitates transcription termination at the rDNA; co-transcriptional 3' end cleavage releases torsional entrainment between polymerases, and Rpa12's cleavage activity is reproduced in vitro, demonstrating its direct mechanistic role in RNAPI termination dynamics. In vitro transcription cleavage assays, in vivo NET-seq/occupancy analysis, mathematical modeling Cell reports Medium 39999833

Source papers

Stage 0 corpus · 44 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
1995 Transcription in archaea: similarity to that in eucarya. Proceedings of the National Academy of Sciences of the United States of America 255 7597027
2007 Functional architecture of RNA polymerase I. Cell 175 18160037
2013 Crystal structure of the 14-subunit RNA polymerase I. Nature 165 24153184
1993 Gene RRN4 in Saccharomyces cerevisiae encodes the A12.2 subunit of RNA polymerase I and is essential only at high temperatures. Molecular and cellular biology 107 8417319
2016 Mechanisms of backtrack recovery by RNA polymerases I and II. Proceedings of the National Academy of Sciences of the United States of America 90 26929337
2016 Molecular Structures of Transcribing RNA Polymerase I. Molecular cell 76 27867008
2016 Structure of RNA polymerase I transcribing ribosomal DNA genes. Nature 73 27842382
1991 Zinc-binding subunits of yeast RNA polymerases. The Journal of biological chemistry 68 1939219
1997 A34.5, a nonessential component of yeast RNA polymerase I, cooperates with subunit A14 and DNA topoisomerase I to produce a functional rRNA synthesis machine. Molecular and cellular biology 64 9121426
2016 Structure of the initiation-competent RNA polymerase I and its implication for transcription. Nature communications 59 27418187
2012 Crosslinking-MS analysis reveals RNA polymerase I domain architecture and basis of rRNA cleavage. Nucleic acids research 59 22396529
1994 The sequence, and its evolutionary implications, of a Thermococcus celer protein associated with transcription. Proceedings of the National Academy of Sciences of the United States of America 40 8171001
2007 Site specific phosphorylation of yeast RNA polymerase I. Nucleic acids research 38 18084032
2015 Ccr4-not regulates RNA polymerase I transcription and couples nutrient signaling to the control of ribosomal RNA biogenesis. PLoS genetics 36 25815716
2019 The cryo-EM structure of a 12-subunit variant of RNA polymerase I reveals dissociation of the A49-A34.5 heterodimer and rearrangement of subunit A12.2. eLife 33 30913026
2006 Purification of an eight subunit RNA polymerase I complex in Trypanosoma brucei. Molecular and biochemical parasitology 33 16730080
2016 Functional architecture of the Reb1-Ter complex of Schizosaccharomyces pombe. Proceedings of the National Academy of Sciences of the United States of America 32 27035982
2021 Structure of the human RNA polymerase I elongation complex. Cell discovery 31 34671025
2014 Heterocyclic cyclohexanone monocarbonyl analogs of curcumin can inhibit the activity of ATP-binding cassette transporters in cancer multidrug resistance. Biochemical pharmacology 29 25543853
2018 The A12.2 Subunit Is an Intrinsic Destabilizer of the RNA Polymerase I Elongation Complex. Biophysical journal 26 29874602
2019 Genetic analyses led to the discovery of a super-active mutant of the RNA polymerase I. PLoS genetics 25 31136569
2020 RNA polymerase I (Pol I) passage through nucleosomes depends on Pol I subunits binding its lobe structure. The Journal of biological chemistry 23 32060094
2017 Multisubunit RNA Polymerase Cleavage Factors Modulate the Kinetics and Energetics of Nucleotide Incorporation: An RNA Polymerase I Case Study. Biochemistry 23 28846843
2019 RNA polymerase III subunits C37/53 modulate rU:dA hybrid 3' end dynamics during transcription termination. Nucleic acids research 21 30407541
2021 The N-terminal domain of the A12.2 subunit stimulates RNA polymerase I transcription elongation. Biophysical journal 19 33737158
2022 RNA polymerase I (Pol I) lobe-binding subunit Rpa12.2 promotes RNA cleavage and proofreading. The Journal of biological chemistry 15 35341765
2006 Molecular cloning, characterization and expression analysis of an ILF2 homologue from Tetraodon nigroviridis. Journal of biochemistry and molecular biology 11 17129403
2021 Defining the Influence of the A12.2 Subunit on Transcription Elongation and Termination by RNA Polymerase I In Vivo. Genes 10 34946888
2001 Isolation and characterization of the fission yeast gene Sprpa12+ reveals that the conserved C-terminal zinc-finger region is dispensable for the function of its product. Molecular & general genetics : MGG 10 11254133
2021 Identification of Candidate Cotton Genes Associated With Fiber Length Through Quantitative Trait Loci Mapping and RNA-Sequencing Using a Chromosome Segment Substitution Line. Frontiers in plant science 8 34970293
2023 Expression of RNA polymerase I catalytic core is influenced by RPA12. PloS one 7 37167337
2021 RNA polymerase I subunit 12 plays opposite roles in cell proliferation and migration. Biochemical and biophysical research communications 7 33984768
2023 The A12.2 Subunit Plays an Integral Role in Pyrophosphate Release of RNA Polymerase I. Journal of molecular biology 5 37355033
2025 Multiple mechanisms of termination modulate the dynamics of RNAPI transcription. Cell reports 4 39999833
2024 Reversible Kinetics in Multi-nucleotide Addition Catalyzed by S. cerevisiae RNA polymerase II Reveal Slow Pyrophosphate Release. Journal of molecular biology 4 38729258
2017 RNA Polymerase-I-Dependent Transcription-coupled Nucleotide Excision Repair of UV-Induced DNA Lesions at Transcription Termination Sites, in Saccharomyces cerevisiae. Photochemistry and photobiology 4 27935059
2017 Ribosomal DNA status inferred from DNA cloud assays and mass spectrometry identification of agarose-squeezed proteins interacting with chromatin (ASPIC-MS). Oncotarget 4 28212567
2016 The RNA polymerase I subunit Rpa12p interacts with the stress-responsive transcription factor Msn4p to regulate lipid metabolism in budding yeast. FEBS letters 4 27637775
2024 RNA Polymerase Subunits and Ribosomal Proteins: An Overview and Their Genetic Impact on Complex Human Traits. Frontiers in bioscience (Landmark edition) 2 38812329
2016 Identification of EhTIF-IA: The putative E. histolytica orthologue of the human ribosomal RNA transcription initiation factor-IA. Journal of biosciences 2 26949087
2016 Microarray data analyses of yeast RNA Pol I subunit RPA12 deletion strain. Genomics data 2 27222810
1996 Analysis of a 62 kb DNA sequence of chromosome X reveals 36 open reading frames and a gene cluster with a counterpart on chromosome XI. Yeast (Chichester, England) 2 8840504
2026 Design and evaluation of selective BET PROTACs with potent antitumor efficacy and safety against acute myeloid leukemia. European journal of medicinal chemistry 0 41740583
2025 An unconventional effector MoRpa12 targeting host nuclei is essential for the development and pathogenicity of Magnaporthe oryzae. Microbiological research 0 40056712

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