Affinage

ZFC3H1

Zinc finger C3H1 domain-containing protein · UniProt O60293

Length
1989 aa
Mass
226.4 kDa
Annotated
2026-04-28
22 papers in source corpus 16 papers cited in narrative 16 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

ZFC3H1 is the central scaffold of the poly(A) exosome targeting (PAXT) connection, a nuclear RNA surveillance pathway that channels polyadenylated noncoding and aberrant RNAs for degradation by the nuclear exosome while simultaneously preventing their export to the cytoplasm. ZFC3H1 bridges the RNA helicase hMTR4 and the poly(A)-binding protein PABPN1 in a manner mutually exclusive with the NEXT complex adaptor ZCCHC8/RBM7, and it competes with ZC3H18 for ARS2 binding through an acidic short linear motif, thereby partitioning CBC-bound transcripts between PAXT- and NEXT-mediated decay (PMID:27871484, PMID:37889751). ZFC3H1 is co-transcriptionally loaded onto nascent RNA in a closed conformation that blocks premature exosome engagement; 3′-end processing of short, few-exon transcripts recruits ZC3H3 and RBM26/27 to trigger conformational opening and exosomal degradation, whereas multi-exon RNAs are instead routed to export (PMID:39461342, PMID:31950173). Through its condensate-forming activity, ZFC3H1 sequesters polyadenylated RNAs away from nuclear speckle–dependent export—cooperating with U1-70K and m6A readers YTHDC1/YTHDC2—and loss of ZFC3H1 causes excess nuclear RNA to titrate PRC2 from chromatin, reducing H3K27me3 and derepressing developmental genes in mouse ESCs (PMID:34530450, PMID:35351812, PMID:39626965, PMID:31722198).

Mechanistic history

Synthesis pass · year-by-year structured walk · 13 steps
  1. 2016 High

    Identification of ZFC3H1 as the core adaptor bridging MTR4 and PABPN1 established the existence of the PAXT connection as a distinct nuclear exosome targeting pathway for polyadenylated RNAs, separate from the NEXT complex.

    Evidence Reciprocal Co-IP, RNA-seq after individual depletions, proteomics in human cells

    PMID:27871484

    Open questions at the time
    • Additional PAXT subunits beyond ZFC3H1/MTR4/PABPN1 were unknown
    • How ZFC3H1 itself is recruited to substrates was unresolved
    • Whether ZFC3H1 has roles beyond exosome-mediated decay was untested
  2. 2017 High

    Demonstrating that ZFC3H1–MTR4 loss causes prematurely terminated and upstream antisense RNAs to leak into the cytoplasm and repress translation revealed that PAXT-mediated surveillance has broad consequences for gene expression beyond RNA turnover.

    Evidence Subcellular fractionation, polysome profiling, siRNA knockdown in human cells

    PMID:28733371

    Open questions at the time
    • The molecular mechanism by which ZFC3H1 prevents cytoplasmic leakage was unclear
    • Whether the translational repression was a direct or indirect consequence of RNA accumulation was not distinguished
  3. 2018 High

    Showing that ZFC3H1 forms nuclear foci containing pA+ RNA and that its depletion allows AlyREF-dependent export of these RNAs established ZFC3H1 as a nuclear retention factor, not merely a degradation factor.

    Evidence Immunofluorescence, siRNA knockdown, epistasis with AlyREF in human cells

    PMID:29768216

    Open questions at the time
    • The biophysical nature of ZFC3H1 nuclear foci was undefined
    • How ZFC3H1 retention activity is mechanistically coupled to or separated from degradation was unknown
  4. 2018 High

    Structural and biochemical characterization of NRDE2 locking MTR4 in a closed conformation that excludes ZFC3H1 binding defined a regulatory mechanism for PAXT assembly at the level of MTR4 accessibility.

    Evidence Crystal structure, mutagenesis of MID domain, Co-IP in human cells

    PMID:30842217

    Open questions at the time
    • Physiological contexts in which NRDE2 inhibition of PAXT is activated were not identified
    • No structure of the MTR4–ZFC3H1 interface itself was obtained
  5. 2019 High

    Discovery of ZC3H3, RBM26, and RBM27 as additional functional PAXT components expanded the complex beyond the core MTR4–ZFC3H1–PABPN1 trimer and showed that multiple accessory factors are individually required for substrate clearance.

    Evidence Proteomic analysis of nuclear pA+-RNA-bound proteins, Co-IP, siRNA with RNA-seq

    PMID:31950173

    Open questions at the time
    • Whether these components are constitutive or context-dependent subunits was unclear
    • Direct RNA-binding specificity of RBM26/27 within PAXT was not resolved
  6. 2019 High

    Linking ZFC3H1 loss to PRC2 eviction from chromatin and derepression of developmental genes in mouse ESCs demonstrated that PAXT-mediated RNA surveillance is coupled to epigenetic regulation via control of nuclear RNA levels.

    Evidence Mouse ESC knockout, ChIP-seq for PRC2/H3K27me3, RNA-IP for PRC2–RNA binding

    PMID:31722198

    Open questions at the time
    • Whether the PRC2 titration effect operates in somatic cell types was not tested
    • Identity of specific RNA species that titrate PRC2 was not determined
  7. 2019 Medium

    Association of ZFC3H1 with the HIV-1 TAR region and its repressive effect on LTR-driven transcription suggested PAXT components participate in viral latency maintenance.

    Evidence ChIP at HIV-1 TAR, siRNA knockdown, latency reactivation in J-Lat cells and PBMCs

    PMID:29554134

    Open questions at the time
    • Mechanism of transcriptional repression at the LTR was not fully resolved
    • Whether ZFC3H1 acts at HIV-1 TAR via RNA degradation or chromatin-level repression was not distinguished
    • Not independently replicated
  8. 2021 High

    Domain mapping revealed that ZFC3H1 uses separable domains for condensate formation and for promoting RNA degradation, establishing that nuclear retention (via condensate-mediated sequestration from speckles) and exosome targeting are mechanistically distinct functions.

    Evidence Live-cell imaging, domain deletion/mutagenesis, RNA trafficking assays in human cells

    PMID:34530450

    Open questions at the time
    • Molecular determinants driving ZFC3H1 phase separation were not fully characterized
    • Whether condensate formation is regulated by signaling or RNA load was untested
  9. 2022 High

    Demonstrating that ZFC3H1 and U1-70K cooperate to retain mRNAs bearing intact 5′ splice sites in nuclear speckles connected PAXT-mediated retention to splice-site-dependent quality control of pre-mRNAs.

    Evidence Fractionated RNA-seq, reporter assays, siRNA knockdown of ZFC3H1/U1-70K, nuclear speckle disruption

    PMID:35351812

    Open questions at the time
    • How 5′SS recognition by U1 snRNP is mechanistically relayed to ZFC3H1 was unknown
    • Whether this pathway acts on all 5′SS-containing transcripts or a subset was unresolved
  10. 2023 High

    Identification of a direct ARS2–ZFC3H1 interaction competing with ZC3H18 for the same ARS2 epitope explained how CBC-bound transcripts are partitioned between PAXT and NEXT branches of exosome targeting.

    Evidence Mutagenesis of ZFC3H1, competition binding assays, RNA-seq after depletion

    PMID:37889751

    Open questions at the time
    • What determines the competitive outcome (PAXT vs NEXT) for a given transcript was not fully resolved
    • Structural basis of the ARS2–ZFC3H1 interaction is lacking
  11. 2023 High

    Showing that PAPγ associates with PAXT through ZFC3H1 and that ZFC3H1 loss abolishes PAXT recruitment to transcription start sites genome-wide established that PAXT couples polyadenylation of PROMPTs with their degradation at the site of transcription.

    Evidence Mass spectrometry, ChIP-seq mapping of ZFC3H1/RBM27/PAPγ, nascent RNA analysis in ZFC3H1 knockout cells

    PMID:37875486

    Open questions at the time
    • Whether PAPγ-mediated polyadenylation is prerequisite for or concurrent with PAXT engagement was unclear
    • Genome-wide mapping was performed in a single cell type
  12. 2024 High

    CLIP-seq and conformational mutagenesis revealed that ZFC3H1 is co-transcriptionally loaded in a closed conformation that shields RNAs from premature degradation, with 3′-end processing of short transcripts triggering opening and exosome engagement — providing a kinetic model for how transcript length determines decay versus export.

    Evidence CLIP-seq, domain mutagenesis distinguishing closed/open conformations, RNA-seq

    PMID:39461342

    Open questions at the time
    • Structural basis of the closed-to-open conformational switch is unresolved
    • How exon number is mechanistically counted to determine the switch remains speculative
  13. 2024 Medium

    Connecting m6A readers YTHDC1/YTHDC2 to ZFC3H1- and U1-70K-dependent nuclear retention showed that m6A modification contributes to the recognition of aberrant 5′SS-containing mRNAs for nuclear sequestration.

    Evidence Co-IP of YTHDC1/2 with ZFC3H1, m6A inhibition, reporter retention assays, nuclear foci imaging

    PMID:39626965

    Open questions at the time
    • Whether m6A acts upstream of or in parallel with ZFC3H1 condensate formation is unknown
    • Single-lab observation awaiting independent confirmation

Open questions

Synthesis pass · forward-looking unresolved questions
  • A high-resolution structural model of the full PAXT complex, the molecular logic by which exon number is sensed to switch ZFC3H1 conformation, and the in vivo regulation of PAXT condensate dynamics remain unresolved.
  • No atomic structure of the ZFC3H1–MTR4 interface or full PAXT complex exists
  • How ZFC3H1 condensates are regulated by signaling or metabolic cues is untested
  • In vivo physiological consequences of ZFC3H1 loss in adult organisms are largely unexplored

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0003723 RNA binding 3 GO:0060090 molecular adaptor activity 3 GO:0098772 molecular function regulator activity 3
Localization
GO:0005634 nucleus 3 GO:0005654 nucleoplasm 3
Pathway
R-HSA-8953854 Metabolism of RNA 5 R-HSA-74160 Gene expression (Transcription) 2 R-HSA-4839726 Chromatin organization 1
Partners
ARS2MTR4PABPN1RBM26RBM27U1-70KYTHDC1ZC3H3
Complex memberships
PAXT connection

Evidence

Reading pass · 16 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2016 ZFC3H1 forms the core of the poly(A) tail exosome targeting (PAXT) connection by acting as a central link between hMTR4 and the nuclear poly(A)-binding protein PABPN1, enabling nuclear exosome degradation of polyadenylated RNAs. ZFC3H1/PABPN1 and ZCCHC8/RBM7 contact hMTR4 in a mutually exclusive manner, revealing that the exosome targets nuclear transcripts of different maturation status by substituting its hMTR4-associating adaptors. Co-immunoprecipitation, RNA-seq after individual depletion, identification of PAXT complex by proteomics Molecular cell High 27871484
2017 Mtr4 and ZFC3H1 form a distinct complex (separate from NEXT) that facilitates nuclear turnover of prematurely terminated RNAs (ptRNAs) and upstream antisense RNAs (uaRNAs). Knockdown of either Mtr4 or ZFC3H1 causes these lncRNAs to accumulate in the cytoplasm, associate with active ribosomes, and globally repress translation. Complex isolation by co-immunoprecipitation, subcellular fractionation, ribosome profiling, siRNA knockdown with polysome analysis Genes & development High 28733371
2018 ZFC3H1 is required for nuclear retention of polyadenylated RNAs. Upon nuclear exosome inactivation, ZFC3H1-containing PAXT components (MTR4, ZFC3H1, PABPN1) concentrate in distinct nuclear foci containing pA+ RNA. In the absence of ZFC3H1, selected pA+ RNAs are exported to the cytoplasm via the mRNA export factor AlyREF, establishing ZFC3H1 as a central nuclear pA+ RNA retention factor that counteracts nuclear export. Co-localization/immunofluorescence, siRNA knockdown, nuclear export assay, co-depletion epistasis with AlyREF Cell reports High 29768216
2018 NRDE2 interacts with MTR4's key residues and locks MTR4 in a closed conformation, thereby inhibiting MTR4 interaction with ZFC3H1 (and the exosome/CBC), negatively regulating exosome function. Structural and biochemical data defined the MTR4-interacting domain (MID) of NRDE2 responsible for this inhibition. Structural analysis, biochemical interaction assays, Co-IP, mutagenesis of MID domain Genes & development High 30842217
2019 ZC3H3, RBM26, and RBM27 are additional components of the PAXT connection required for its function. ZC3H3 interacts directly with the MTR4-ZFC3H1 core dimer, and loss of any of these new components results in accumulation of PAXT substrates. Proteomic characterization of nuclear pA+-RNA bound proteomes, Co-IP, siRNA knockdown with RNA-seq substrate analysis Nucleic acids research High 31950173
2019 Knockout of ZFC3H1 impairs mouse ESC differentiation and leads to de-repression of PRC2 target developmental genes. Elevated levels of unspecific RNA bind to PRC2 components in Zfc3h1-/- cells, compromising PRC2 complex stability and reducing H3K27 methylation, suggesting that excess nuclear RNA caused by loss of PAXT sequesters PRC2 from chromatin. Mouse ESC knockout, ChIP-seq for PRC2/H3K27me3, RNA-IP showing RNA binding to PRC2 components, RNA-seq Cell reports High 31722198
2019 ZFC3H1 physically associates with the HIV-1 TAR region along with RRP6, MTR4, and ZCCHC8, repressing HIV-1 transcriptional output and RNAPII recruitment to the LTR. Knockdown of ZFC3H1 increases GFP expression in J-Lat cells and reactivates HIV-1 from latently infected PBMCs, with concomitant increase in active histone marks. ChIP (association with HIV-1 TAR), siRNA knockdown, flow cytometry in J-Lat reporter cells, latency reactivation in PBMCs PLoS pathogens Medium 29554134
2021 Upon exosome inactivation, ZFC3H1 forms nuclear condensates that prevent RNA trafficking to nuclear speckles (where RNAs gain export competence). Systematic domain mapping showed ZFC3H1 uses distinct domains for condensation and for promoting RNA degradation, and condensation activity is required for preventing RNA trafficking to nuclear speckles but not for RNA degradation itself. Live-cell imaging of condensate formation, domain deletion/mutagenesis mapping, RNA trafficking assays, RNA-seq Nucleic acids research High 34530450
2022 ZFC3H1 promotes nuclear retention and degradation of mRNAs containing intact 5' splice site (5'SS) motifs (including intronic polyadenylated transcripts) by sequestering them into nuclear speckles. U1-70K (U1 snRNP component) functions in the same nuclear retention pathway as ZFC3H1, and disassembly of nuclear speckles impairs this retention. High-throughput sequencing of fractionated RNA, reporter mRNA assays, siRNA knockdown of ZFC3H1/U1-70K, nuclear speckle disruption experiments RNA (New York, N.Y.) High 35351812
2023 Mutational analysis of ZFC3H1 uncovered a direct ARS2-ZFC3H1 interaction that defines a separate PAXT branch targeting short adenylated RNAs. ZFC3H1 and ZC3H18 compete for a common ARS2 epitope via similar acidic-rich short linear motifs, such that ZC3H18 promotes NEXT function while simultaneously antagonizing PAXT activity. Mutagenesis of ZFC3H1, Co-IP, competition binding assays, RNA-seq after depletion Cell reports High 37889751
2023 Polyadenosine polymerase gamma (PAPγ) associates with the PAXT complex through ZFC3H1. Loss of ZFC3H1 abolishes recruitment of all PAXT subunits including PAPγ to transcription start sites genome-wide and concomitantly increases PROMPT ncRNA abundance at those sites. PAPγ, MTR4, and ZFC3H1 are all implicated in polyadenylation of PROMPTs. Proteomic analysis (mass spectrometry), ChIP-seq genome-wide mapping of ZFC3H1/RBM27/PAPγ, ZFC3H1 knockout with nascent RNA analysis Nature communications High 37875486
2024 ZFC3H1 is co-transcriptionally loaded onto the first exon/intron of RNA precursors. During loading, ZFC3H1 adopts a 'closed' conformation that blocks exosome recruitment and prevents premature degradation. Upon 3'-end processing, short RNAs with fewer exons recruit transient PAXT components ZC3H3 and RBM26/27 to the 3' end, triggering ZFC3H1 'opening' and subsequent exosomal degradation, while longer RNAs with more exons are directed to nuclear export. CLIP-seq for co-transcriptional loading, domain mutagenesis distinguishing closed/open ZFC3H1 conformations, RNA-seq after depletion of components Molecular cell High 39461342
2024 YTHDC1 and YTHDC2 (m6A reader proteins) interact with ZFC3H1 and U1-70K and are required for nuclear retention of mRNAs with intact 5'SS motifs. Disruption of m6A deposition inhibits nuclear retention of these transcripts and their accumulation in YTHDC1-enriched foci adjacent to nuclear speckles. Co-IP of YTHDC1/2 with ZFC3H1, m6A inhibition, reporter retention assays, imaging of nuclear foci Life science alliance Medium 39626965
2014 ZFC3H1 was identified as a direct binding protein of celastramycin A by pull-down assay. Knockdown of ZFC3H1 reduced IL-8 expression in TNFα-stimulated cells, and reporter assays showed ZFC3H1 participates in transcriptional activation of IL-8. ZFC3H1 may also indirectly interact with ERCC1 in a DNA repair complex. Celastramycin A pull-down assay, siRNA knockdown, IL-8 reporter assay PloS one Low 25268596
2022 ZFC3H1 participates in telomerase RNA (hTR) biogenesis via pathways related to polyadenylated RNA degradation, as knockdown of ZFC3H1 affects hTR isoform abundance and localization. siRNA knockdown of ZFC3H1 with RT-qPCR and cellular fractionation of hTR isoforms Biomedicines Low 35740297
2024 In lung adenocarcinoma, lncRNA MSL3P1 competes with ZFC3H1 for binding to CUL3 mRNA, preventing ZFC3H1-mediated degradation and nuclear retention of CUL3 mRNA and enabling its cytoplasmic export and translation, which activates EMT signaling. RNA pulldown/RIP showing competitive binding, siRNA knockdown, CUL3 mRNA stability/fractionation assays Molecular cancer research Low 38718076

Source papers

Stage 0 corpus · 22 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2016 Identification of a Nuclear Exosome Decay Pathway for Processed Transcripts. Molecular cell 227 27871484
2017 An Mtr4/ZFC3H1 complex facilitates turnover of unstable nuclear RNAs to prevent their cytoplasmic transport and global translational repression. Genes & development 109 28733371
2018 The RNA Exosome Adaptor ZFC3H1 Functionally Competes with Nuclear Export Activity to Retain Target Transcripts. Cell reports 72 29768216
1999 cSrc is a major cytosolic tyrosine kinase in vascular tissue. Canadian journal of physiology and pharmacology 71 10543724
2020 The human ZC3H3 and RBM26/27 proteins are critical for PAXT-mediated nuclear RNA decay. Nucleic acids research 60 31950173
2019 Identification of Celastramycin as a Novel Therapeutic Agent for Pulmonary Arterial Hypertension. Circulation research 46 31195886
2019 NRDE2 negatively regulates exosome functions by inhibiting MTR4 recruitment and exosome interaction. Genes & development 44 30842217
2007 A gene signature of 8 genes could identify the risk of recurrence and progression in Dukes' B colon cancer patients. Oncology reports 44 17390049
2019 A Functional Link between Nuclear RNA Decay and Transcriptional Control Mediated by the Polycomb Repressive Complex 2. Cell reports 34 31722198
2022 ZFC3H1 and U1-70K promote the nuclear retention of mRNAs with 5' splice site motifs within nuclear speckles. RNA (New York, N.Y.) 21 35351812
2018 Nuclear RNA surveillance complexes silence HIV-1 transcription. PLoS pathogens 20 29554134
2021 ZFC3H1 prevents RNA trafficking into nuclear speckles through condensation. Nucleic acids research 19 34530450
2023 Dual agonistic and antagonistic roles of ZC3H18 provide for co-activation of distinct nuclear RNA decay pathways. Cell reports 14 37889751
2023 PAPγ associates with PAXT nuclear exosome to control the abundance of PROMPT ncRNAs. Nature communications 12 37875486
2014 ZFC3H1, a zinc finger protein, modulates IL-8 transcription by binding with celastramycin A, a potential immune suppressor. PloS one 12 25268596
2020 Use of peripheral blood transcriptomic biomarkers to distinguish high-grade cervical squamous intraepithelial lesions from low-grade lesions. Oncology letters 11 32765790
2022 Construction of AP003469.4-miRNAs-mRNAs ceRNA network to reveal potential biomarkers for hepatocellular carcinoma. American journal of cancer research 10 35530270
2024 N-6-methyladenosine (m6A) promotes the nuclear retention of mRNAs with intact 5' splice site motifs. Life science alliance 6 39626965
2022 Role of RNA Biogenesis Factors in the Processing and Transport of Human Telomerase RNA. Biomedicines 5 35740297
2024 Dual modes of ZFC3H1 confer selectivity in nuclear RNA sorting. Molecular cell 4 39461342
2024 Long Noncoding RNA MSL3P1 Regulates CUL3 mRNA Cytoplasmic Transport and Stability and Promotes Lung Adenocarcinoma Metastasis. Molecular cancer research : MCR 3 38718076
2024 Genome-wide association study for conformation traits in Ayrshire cattle. Animal science journal = Nihon chikusan Gakkaiho 1 39165009