Affinage

TUT7

Terminal uridylyltransferase 7 · UniProt Q5VYS8

Length
1495 aa
Mass
171.2 kDa
Annotated
2026-04-28
14 papers in source corpus 11 papers cited in narrative 11 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

TUT7 (ZCCHC6/TENT3B) is a terminal uridylyltransferase that controls RNA fate by adding non-templated uridine residues to microRNA precursors, mature miRNAs, and mRNA degradation intermediates. Its catalytic module performs distributive mono-uridylation of group II pre-miRNAs with 1-nt 3ʹ overhangs to restore the canonical 2-nt overhang for Dicer processing, while in the presence of Lin28, a separate Lin28-interacting module drives processive oligo-uridylation of pre-let-7 to block let-7 biogenesis—a switch governed by crystal-structure-resolved duplex-RNA-binding and uracil-specific recognition pockets (PMID:22898984, PMID:25979828, PMID:28671666). TUT7 cooperates with the 3ʹ-to-5ʹ exonuclease 3ʹhExo to uridylate histone mRNA degradation intermediates, facilitating exosome-mediated decay during S-phase exit (PMID:27609902, PMID:36041871). Beyond precursor processing, TUT7 selectively mono-uridylates specific mature miRNAs to regulate their stability, and it participates in a DIS3L2-dependent RNA surveillance pathway that becomes essential in cancer cells lacking the SKI-complex stabilizer FOCAD (PMID:25223788, PMID:36071058, PMID:39235218).

Mechanistic history

Synthesis pass · year-by-year structured walk · 10 steps
  1. 2012 High

    Establishing TUT7 as a bona fide TUTase redundant with TUT4 resolved the question of which enzymes mediate Lin28-dependent pre-let-7 uridylation in embryonic stem cells and identified the C2H2-type zinc finger as the Lin28-interaction domain.

    Evidence In vitro uridylation assays, domain dissection, and ES cell depletion experiments

    PMID:22898984

    Open questions at the time
    • No structural information on TUT7–Lin28 interface
    • Relative contribution of TUT7 vs TUT4 in vivo not quantified
  2. 2014 High

    Demonstrating that TUT7 selectively mono-uridylates a subset of mature miRNAs via a bipartite sequence motif showed that TUT7 activity extends beyond precursor processing and can stabilize rather than destabilize target miRNAs.

    Evidence In vitro uridylation, small RNA sequencing of TUTase-depleted cells, zebrafish knockdown

    PMID:25223788

    Open questions at the time
    • Structural basis of motif recognition unknown
    • Mechanism by which mono-U stabilizes miRNAs not defined
  3. 2015 High

    Single-molecule and biochemical dissection revealed that pre-miRNA 3ʹ overhang length is the key structural determinant switching TUT7 between mono-uridylation (promoting Dicer processing) and oligo-uridylation (promoting degradation), and that TUT7 acts distributively in the absence of Lin28.

    Evidence Single-molecule FRET, deep sequencing, in vitro uridylation with defined substrates

    PMID:25979828

    Open questions at the time
    • How cofactors other than Lin28 modulate processivity was unclear
    • In vivo validation of overhang-length model not provided
  4. 2016 Medium

    Identification of TUT7 as the primary TUTase for histone mRNA uridylation, cooperating with 3ʹhExo, expanded TUT7 substrates from miRNAs to replication-dependent mRNAs and linked it to cell-cycle-dependent mRNA turnover.

    Evidence High-throughput sequencing of histone mRNA 3ʹ ends with selective siRNA knockdowns

    PMID:27609902

    Open questions at the time
    • Knockdown-only evidence; genetic confirmation needed
    • Mechanism of TUT7 recruitment to histone mRNAs unresolved
  5. 2017 High

    Crystal structures of TUT7's catalytic module and biochemical reconstitution of the Lin28/pre-let-7/TUT7 ternary complex provided an atomic-level explanation for the mono- to oligo-uridylation switch, revealing a duplex-RNA-binding pocket in the catalytic module and uracil-specific interactions in the ZK2 subdomain.

    Evidence X-ray crystallography, domain mutagenesis, in vitro reconstitution

    PMID:28671666

    Open questions at the time
    • Full-length TUT7 structure not determined
    • Dynamics of processivity transition not captured structurally
  6. 2019 Medium

    A knockout mouse model showed that TUT7-mediated uridylation of miR-26b derepresses IL-6 in chondrocytes, linking TUT7 to inflammatory gene regulation and osteoarthritis pathology.

    Evidence Zcchc6-knockout mice with surgically induced OA, mRNA stability assays, deep sequencing, rescue

    PMID:30302948

    Open questions at the time
    • Directness of TUT7→miR-26b→IL-6 axis versus other miRNA targets not fully dissected
    • Relevance beyond murine surgical OA model unclear
  7. 2022 High

    CRISPR knockouts confirmed that TUT7 and 3ʹhExo cooperate sequentially—3ʹhExo initiates degradation into the stem-loop and TUT7 uridylates intermediates for exosome-mediated decay—establishing the ordered mechanism of histone mRNA turnover.

    Evidence CRISPR knockout of TUT7 and 3ʹhExo, sequencing of histone mRNA ends, cell synchronization

    PMID:36041871

    Open questions at the time
    • How TUT7 is recruited specifically to histone mRNA intermediates remains unknown
    • Exosome recognition of oligo-U tails not mechanistically defined
  8. 2022 High

    Isogenic knockout studies separated TUT4 and TUT7 substrate specificities for mature miRNAs, showing TUT7 is largely dispensable for global miRNA uridylation but specifically upregulates the miR-888 cluster, while both enzymes negatively regulate miR-181b and miR-222.

    Evidence Isogenic CRISPR KO HEK293T lines, deep sequencing, Northern blot, rescue experiments

    PMID:36071058

    Open questions at the time
    • Mechanism of TUT7 selectivity for miR-888 cluster undefined
    • Functional consequences of miR-888 upregulation not explored
  9. 2024 Medium

    Identification of a synthetic-lethal relationship between FOCAD loss and TUT7/DIS3L2 dependency revealed that TUT7 participates in an RNA surveillance pathway that becomes essential when canonical exosome targeting via the SKI complex is compromised.

    Evidence CRISPR screens, small-molecule TUT4/7 inhibitors, FOCAD rescue, in vitro and in vivo proliferation assays

    PMID:39235218

    Open questions at the time
    • Identity of aberrant RNA substrates in FOCAD-null cells not determined
    • Mechanistic connection between SKI complex loss and TUT7 dependency is model-level
  10. 2025 Medium

    Placing TUT7 in the ZAP/TRIM25/KHNYN antiviral pathway as the enzyme that uridylates 5ʹ cleavage fragments for DIS3L2-dependent degradation extended TUT7 function to innate immune RNA decay.

    Evidence (preprint) RNase-resistant co-immunoprecipitation, epistasis ordering, sequencing of cleavage and uridylation products, CRISPR/siRNA depletion

    PMID:bio_10.1101_2025.04.28.650959

    Open questions at the time
    • Not yet peer-reviewed
    • Stoichiometry and assembly of ZAP–TUT7–DIS3L2 complex not characterized
    • Relative contributions of TUT4 vs TUT7 in this pathway not separated

Open questions

Synthesis pass · forward-looking unresolved questions
  • A full-length structure of TUT7, the mechanism by which TUT7 is recruited to specific mRNA substrates (histone mRNAs, viral RNA fragments), and the structural basis for its selectivity toward particular mature miRNAs remain unresolved.
  • No full-length TUT7 structure
  • Recruitment mechanism to non-miRNA substrates unknown
  • Basis for miR-888 cluster specificity undefined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0016740 transferase activity 7 GO:0003723 RNA binding 2
Localization
GO:0005829 cytosol 2
Pathway
R-HSA-8953854 Metabolism of RNA 7 R-HSA-1640170 Cell Cycle 2 R-HSA-168256 Immune System 1
Partners
3'HEXODIS3L2LIN28ALIN28BTRIM25TUT4ZAP

Evidence

Reading pass · 11 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2012 TUT7 (Zcchc6) functions as an alternative TUTase that cooperates with Lin28 to uridylate pre-let-7 microRNAs, redundantly with TUT4 (Zcchc11), to block let-7 biogenesis in embryonic stem cells. A C2H2-type zinc finger domain of Zcchc11 (and by implication TUT7) mediates the functional interaction with Lin28. Biochemical reconstitution assays, in vitro uridylation, domain dissection, ES cell depletion experiments RNA (New York, N.Y.) High 22898984
2014 TUT7 (Zcchc6) selectively mono-uridylates a specific subset of mature miRNAs (involved in cell differentiation and Hox gene control) through recognition of a bipartite sequence motif in the miRNA, and this uridylation stabilizes those miRNAs; TUTase depletion leads to loss of 3' mono-uridylation and a concomitant increase in non-templated 3' mono-adenylation. In vitro uridylation assays, small RNA sequencing of TUTase-depleted cells, biochemical motif definition, zebrafish knockdown with developmental phenotype Nucleic acids research High 25223788
2015 TUT7 recognizes the overhang structure of pre-miRNAs as the key determinant: for group II pre-miRNAs with a 1-nt 3' overhang, TUT7 performs mono-uridylation to restore the canonical 2-nt overhang and promote Dicer processing; for pre-miRNAs with a recessed 3' end, TUT7 generates an oligo-U tail leading to degradation. In the absence of Lin28, TUT7 uses a distributive (not processive) mode for both mono- and oligo-uridylation, with overhang length dictating frequency of TUT7-RNA interaction. Biochemistry, single-molecule FRET, deep sequencing, in vitro uridylation assays with defined substrates The EMBO journal High 25979828
2017 TUT7 has two functional modules: a catalytic module (CM) sufficient for mono-uridylation, and a Lin28-interacting module (LIM) required for oligo-uridylation. A crystal structure of the TUT7 CM trapped in mono-uridylation state revealed a duplex-RNA-binding pocket orienting group II pre-let-7 hairpins to favor monoU addition. The ZK domain of Lin28 drives formation of a stable ternary complex (Lin28/pre-let-7/TUT7 LIM) to switch to processive oligo-uridylation, and TUT7's ZK2 subdomain engages the growing oligo-U tail through uracil-specific interactions. Crystal structure determination, domain mutagenesis, in vitro uridylation assays, biochemical reconstitution of ternary complex Nature structural & molecular biology High 28671666
2016 TUT7 is specifically responsible for oligouridylation of histone mRNAs at the 3' end and uridylation of degradation intermediates in the stem-loop during histone mRNA degradation; TUT7 and 3'hExo cooperate in trimming and uridylating histone mRNAs. TUT4 knockdown had minimal effect, indicating TUT7 is the primary TUTase for this substrate. High-throughput sequencing of histone mRNA 3' ends, siRNA knockdown of TUT7, TUT4, and 3'hExo, comparison of uridylation patterns RNA (New York, N.Y.) Medium 27609902
2022 Knockout of TUT7 (TENT3B/ZCCHC6) prevents uridylation of histone mRNA degradation intermediates and slows the rate of histone mRNA degradation, while 3'hExo knockout prevents initiation of 3'-to-5' degradation and stabilizes histone mRNA. The two enzymes cooperate: 3'hExo initiates degradation into the stem-loop and TUT7 uridylates the resulting intermediates to facilitate exosome-mediated decay. CRISPR knockout of TUT7 and 3'hExo, high-throughput sequencing of histone mRNA ends, cell synchronization assays RNA (New York, N.Y.) High 36041871
2022 In isogenic knockout cell lines, TUT4 uridylates most miRNAs broadly whereas TUT7 is largely dispensable for general miRNA uridylation but specifically upregulates the miR-888 cluster; TUT4 and TUT7 together negatively regulate miR-181b and miR-222 via distinct mechanisms. Uridylation loss (but not adenylation loss) leads to dysregulation of specific miRNA levels. Isogenic CRISPR knockout HEK293T lines (single and combinatorial), deep sequencing, Northern blot, in vitro uridylation assays, rescue experiments Nature communications High 36071058
2019 ZCCHC6 (TUT7) promotes IL-6 expression in chondrocytes by stabilizing IL-6 transcripts and by uridylating miR-26b (reducing its abundance), which abrogates miR-26b-mediated repression of IL-6. Zcchc6-knockout mice show reduced IL-6 and decreased OA severity in a surgical model. siRNA knockdown, actinomycin D mRNA stability assay, deep sequencing of miRNA 3' uridylation, Zcchc6-/- mouse model with surgically induced OA, rescue by Zcchc6 reintroduction Arthritis & rheumatology (Hoboken, N.J.) Medium 30302948
2024 In FOCAD-deficient cancer cells, TUT7 (but not TUT4) functions as part of a salvage mechanism with DIS3L2 to degrade aberrant RNA; loss of FOCAD disrupts SKI complex stability posttranscriptionally, making cells dependent on TUT7/DIS3L2 for viability. Small-molecule TUT4/7 inhibitors demonstrate antiproliferative activity specifically in FOCAD-deleted cancer cells in vitro and in vivo. CRISPR knockout screens, public functional genomics data, small-molecule TUT4/7 inhibitors, FOCAD rescue experiments, in vitro and in vivo antiproliferative assays Molecular cancer therapeutics Medium 39235218
2025 In the ZAP-mediated RNA decay pathway, TUT4/TUT7 uridylate the 5' cleavage fragment generated by KHNYN endonuclease cleavage of viral RNA, and this uridylated fragment is then degraded by DIS3L2; ZAP and TRIM25 interact with TUT7, DIS3L2, and XRN1 in an RNase-resistant manner, placing TUT7 in an RNA decay complex downstream of ZAP/TRIM25/KHNYN. Co-immunoprecipitation (RNase-resistant), epistasis ordering of pathway steps, sequencing of RNA cleavage and uridylation products, CRISPR/siRNA depletion of pathway components bioRxivpreprint Medium bio_10.1101_2025.04.28.650959
2025 TUT7 uridylates MCPIP1 mRNA, reducing its stability and thereby decreasing MCPIP1 protein levels; loss of MCPIP1 impairs the TRAF6-BECN1 autophagy pathway and promotes pterygium fibroblast migration and proliferation. In vitro transcription and uridylation experiments, co-immunoprecipitation, ubiquitination assays, transwell migration and wound-healing assays, siRNA knockdown Investigative ophthalmology & visual science Low 40238115

Source papers

Stage 0 corpus · 14 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2012 Lin28-mediated control of let-7 microRNA expression by alternative TUTases Zcchc11 (TUT4) and Zcchc6 (TUT7). RNA (New York, N.Y.) 176 22898984
2015 TUT7 controls the fate of precursor microRNAs by using three different uridylation mechanisms. The EMBO journal 88 25979828
2014 Selective microRNA uridylation by Zcchc6 (TUT7) and Zcchc11 (TUT4). Nucleic acids research 85 25223788
2017 Multi-domain utilization by TUT4 and TUT7 in control of let-7 biogenesis. Nature structural & molecular biology 45 28671666
2022 TENT2, TUT4, and TUT7 selectively regulate miRNA sequence and abundance. Nature communications 42 36071058
2016 TUT7 catalyzes the uridylation of the 3' end for rapid degradation of histone mRNA. RNA (New York, N.Y.) 40 27609902
2019 Genetic Inactivation of ZCCHC6 Suppresses Interleukin-6 Expression and Reduces the Severity of Experimental Osteoarthritis in Mice. Arthritis & rheumatology (Hoboken, N.J.) 31 30302948
2024 The Uridylyl Transferase TUT7-Mediated Accumulation of Exosomal miR-1246 Reprograms TAMs to Support CRC Progression. Advanced science (Weinheim, Baden-Wurttemberg, Germany) 18 38342611
2017 The RNA uridyltransferase Zcchc6 is expressed in macrophages and impacts innate immune responses. PloS one 17 28665939
2024 Targeting the Synthetic Lethal Relationship between FOCAD and TUT7 Represents a Potential Therapeutic Opportunity for TUT4/7 Small-Molecule Inhibitors in Cancer. Molecular cancer therapeutics 5 39235218
1997 [Menogaril (TUT-7) late phase II study for malignant lymphoma, adult T-cell leukemia and lymphoma (ATLL)]. Gan to kagaku ryoho. Cancer & chemotherapy 4 9279345
2022 Knockouts of TUT7 and 3'hExo show that they cooperate in histone mRNA maintenance and degradation. RNA (New York, N.Y.) 3 36041871
2020 Induction of ZCCHC6 expression in peripheral blood mononuclear cells by HNSCC secretions. Gene 3 32526260
2025 TUT7-Mediated Uridine Degradation of MCPIP1 in the Pterygium to Regulate TRAF6-Mediated Autophagy. Investigative ophthalmology & visual science 2 40238115