Affinage

ZHX1

Zinc fingers and homeoboxes protein 1 · UniProt Q9UKY1

Length
873 aa
Mass
98.1 kDa
Annotated
2026-06-11
20 papers in source corpus 14 papers cited in narrative 14 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

ZHX1 is a nuclear zinc-finger/homeodomain transcription factor that functions principally as a transcriptional repressor but can also act as a context-specific activator (PMID:8713137, PMID:12237128). It harbors two C2-H2 zinc fingers and five homeodomains, and represses transcription through an acidic C-terminal domain (residues 831–873), homodimerizes via its first homeodomain (residues 272–432) as a requirement for full repressor activity, and enters the nucleus through an arginine-rich C-terminal NLS (residues 734–768) (PMID:12237128). ZHX1 was first identified as a direct binding partner of the NF-YA subunit of the CCAAT-binding factor NF-Y (PMID:10441475), and it integrates into repressive transcriptional machinery by binding the de novo DNA methyltransferase DNMT3B—engaging the DNMT3B PWWP domain through its homeobox motifs and enhancing DNMT3B-mediated repression—and by binding the corepressor BS69 via a PxLxP motif (PMID:17303076, PMID:17127430). ZHX1 activity and stability are tuned by Ubc9-mediated SUMOylation at K159, K454, and K626, which modulates its ubiquitination and repressor function (PMID:23686912). Beyond repression, ZHX1 acts as a co-activator: it partners with hnRNPA1 through residues in its second zinc finger to drive a transcriptional program for cardiac progenitor specification (PMID:37452012), and it promotes transcription of the mitochondrial ribosomal protein genes Mrps15 and Mrps21 to protect mitochondrial function in hypertensive heart disease (PMID:42162768). In cancer cells ZHX1 restrains proliferation by enforcing G1/S arrest and promoting apoptosis (PMID:26722361, PMID:28559996).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 1996 High

    Establishing that ZHX1 encodes a zinc-finger-class homeodomain protein defined it as a candidate transcription factor and set the structural framework for all later mechanistic work.

    Evidence cDNA cloning and ORF sequencing with Northern blot expression profiling in mouse

    PMID:8713137

    Open questions at the time
    • No DNA-binding specificity or target genes identified
    • Function inferred from domain content, not tested
  2. 1999 Medium

    Identifying ZHX1 as a direct NF-YA interactor connected it to the CCAAT-binding transcriptional machinery, giving its first defined molecular partner.

    Evidence Yeast two-hybrid screen of a human liver cDNA library using NF-YA as bait

    PMID:10441475

    Open questions at the time
    • Single-method interaction without reciprocal in-cell validation
    • Functional consequence of NF-YA binding not defined
  3. 2002 High

    Domain mapping defined ZHX1 as a repressor and assigned its repression, dimerization, and nuclear-targeting functions to discrete regions, converting it from a presumed factor to a mechanistically dissected one.

    Evidence Mammalian one-hybrid, GFP-fusion localization and truncation interaction assays in HEK293; independent yeast two-hybrid homodimerization with GFP localization

    PMID:12062805 PMID:12237128

    Open questions at the time
    • Direct DNA target sequences not identified
    • Cofactors mediating repression not yet known
  4. 2003 Medium

    Mapping the ZHX1 promoter showed how ZHX1 expression is itself controlled, identifying PEA3 and YY1 as synergistic upstream activators.

    Evidence Luciferase reporter deletion analysis and EMSA with supershift in mouse

    PMID:12527199

    Open questions at the time
    • Regulation in physiological/disease contexts not tested
    • Single lab
  5. 2007 Medium

    Discovery of DNMT3B and BS69 partnerships placed ZHX1 within repressive chromatin/corepressor machinery, explaining how it executes repression mechanistically.

    Evidence Reciprocal Co-IP, co-localization and transcriptional repression assays (DNMT3B); domain-mapped PxLxP-MYND interaction and reporter assays (BS69)

    PMID:17127430 PMID:17303076

    Open questions at the time
    • Endogenous target genes co-regulated by these complexes not defined
    • Whether DNMT3B recruitment alters DNA methylation at ZHX1 targets untested
  6. 2013 High

    Identifying Ubc9-mediated SUMOylation at three lysines established a post-translational control layer governing ZHX1 stability and activity.

    Evidence Yeast two-hybrid, Co-IP, site-directed mutagenesis of SUMO acceptor sites and SUMOylation assays

    PMID:23686912

    Open questions at the time
    • Signals triggering ZHX1 SUMOylation unknown
    • SUMO-dependent partner switching not characterized
  7. 2014 Medium

    A solution NMR structure of a ZHX1 homeodomain provided atomic-level structural information for one of its functional modules.

    Evidence Solution NMR structure determination

    PMID:24941917

    Open questions at the time
    • No functional validation of the solved homeodomain
    • Full-length or multi-domain architecture unresolved
  8. 2016 Medium

    Loss- and gain-of-function studies in cancer cells linked ZHX1 to cell-cycle arrest and apoptosis, assigning it a tumor-suppressive cellular role.

    Evidence siRNA/overexpression in gastric and cholangiocarcinoma cells with cell-cycle, apoptosis and invasion readouts

    PMID:26722361 PMID:27835650

    Open questions at the time
    • Direct transcriptional targets driving these effects not defined
    • EGR1 mediation only correlative
  9. 2017 Medium

    Epistasis placing ZHX1 upstream of PUMA defined a specific pro-apoptotic effector pathway downstream of ZHX1 in hepatocellular carcinoma.

    Evidence siRNA, Western blot and xenograft model

    PMID:28559996

    Open questions at the time
    • Whether ZHX1 directly transcribes PUMA untested
    • Single lab
  10. 2023 High

    Identifying the ZHX1/hnRNPA1 co-activator complex demonstrated that ZHX1 can activate transcription and drive a developmental program for cardiac progenitor specification.

    Evidence Reciprocal Co-IP, residue-level domain mapping, and loss-of-function in mouse and human ESC differentiation with transcriptomics

    PMID:37452012

    Open questions at the time
    • Direct target promoters bound by the complex not fully mapped
    • Mechanism of repressor-to-activator switch unknown
  11. 2026 Medium

    Demonstrating that ZHX1 drives Mrps15/Mrps21 transcription to protect mitochondria established a concrete activator target set and a cardioprotective function.

    Evidence Overexpression, mithramycin activation, combined Mrps15/Mrps21 siRNA rescue, mitochondrial respiration assays and in vivo L-NAME model

    PMID:42162768

    Open questions at the time
    • Direct binding of ZHX1 to Mrps15/Mrps21 promoters not shown
    • Coactivator partners in this context not identified

Open questions

Synthesis pass · forward-looking unresolved questions
  • What determines whether ZHX1 acts as a repressor versus an activator at a given locus, and the genome-wide set of its direct DNA targets, remain unresolved.
  • No genome-wide ZHX1 binding map
  • Molecular basis of the repressor/activator switch unknown
  • Direct DNA recognition sequence undefined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140110 transcription regulator activity 4 GO:0003677 DNA binding 2
Localization
GO:0005634 nucleus 3
Pathway
R-HSA-74160 Gene expression (Transcription) 4
Partners
BS69DNMT3BHNRNPA1NFYAUBE2I

Evidence

Reading pass · 14 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1996 ZHX1 (zhx-1) encodes a novel protein of 873 amino acids containing two C2-H2 zinc fingers and five homeodomains, classifying it as a ZF-class homeodomain transcription factor; mRNA is widely expressed in adult mouse with preferential expression in brain. cDNA cloning, ORF sequencing, Northern blot analysis Biochemical and biophysical research communications High 8713137
1999 Human ZHX1 was isolated as a direct binding partner of the NF-YA subunit of the heterotrimeric transcription factor NF-Y (CCAAT-binding protein); interaction identified by yeast two-hybrid screening of a human liver cDNA library using NF-YA as bait. Yeast two-hybrid screen, cDNA library screening, Northern blot Biochemical and biophysical research communications Medium 10441475
2002 ZHX1 functions as a transcriptional repressor: its acidic C-terminal region (amino acids 831–873) is the repressor domain; homodimerization via homeodomain 1 (amino acids 272–432) is required for full repressor activity; nuclear localization signal maps to an arginine-rich region (amino acids 734–768). Mammalian one-hybrid assay, GFP-fusion transfection into HEK293 cells, protein-protein interaction assays with truncation mutants Biochemical and biophysical research communications High 12237128
2002 Rat ZHX1 forms a homodimer, as identified by yeast two-hybrid screening of an ovarian granulosa cell cDNA library; full-length ZHX1 fused to GFP localizes to the nucleus in HEK293 cells. Yeast two-hybrid, GFP fusion transfection, Northern blot Gene Medium 12062805
2003 Transcription of the mouse ZHX1 gene is driven by two positive cis-acting elements (Box A and Box B) in the proximal promoter; PEA3 binds Box A and YY1 binds Box B, and they synergistically stimulate ZHX1 transcription. Luciferase reporter assays with 5'- and 3'-deletion constructs, electrophoretic mobility shift assay (EMSA) with antibodies and specific competitors Gene Medium 12527199
2007 ZHX1 directly binds DNMT3B; the N-terminal PWWP domain of DNMT3B interacts with the homeobox motifs of ZHX1; both proteins co-localize in the nucleus; ZHX1 enhances DNMT3B-mediated transcriptional repression when DNMT3B is directly targeted to DNA. Yeast two-hybrid, co-immunoprecipitation (in vivo and in vitro), co-localization, transcriptional repression assay Biochemical and biophysical research communications High 17303076
2007 Corepressor BS69 interacts with ZHX1 through its C-terminal MYND domain binding to the PxLxP motif of ZHX1; this interaction suppresses BS69-mediated transcriptional activation in HEK293 cells. Co-transfection with wild-type and PxLxP-mutant ZHX1, transcriptional reporter assay, domain mapping Frontiers in bioscience Medium 17127430
2013 ZHX1 is SUMOylated by the SUMO E2 conjugating enzyme Ubc9 at lysine residues K159, K454, and K626 using SUMO1; SUMOylation regulates ZHX1 protein stability, ubiquitination, and transcriptional repression activity. Yeast two-hybrid (interaction screen), co-immunoprecipitation, co-localization, site-directed mutagenesis of SUMO acceptor sites, SUMOylation assay Journal of cellular biochemistry High 23686912
2014 Solution NMR structures of a ZHX1 homeodomain were solved, providing structural characterization of this domain. Solution NMR structure determination Journal of structural and functional genomics Medium 24941917
2016 ZHX1 induces G1/S cell-cycle arrest by decreasing cyclin D1 and cyclin E expression, and induces apoptosis by downregulating Bcl2 and upregulating Bax and cleaved caspase-3 in gastric cancer cells. siRNA knockdown and overexpression in gastric cancer cell lines, cell-cycle analysis, Western blot for cyclins and apoptosis markers Journal of Cancer Medium 26722361
2016 ZHX1 knockdown decreases cholangiocarcinoma cell proliferation, migration, and invasion; EGR1 was identified as a partial downstream mediator of ZHX1's effect on CCA cell proliferation. siRNA knockdown, overexpression, in silico analysis, immunohistochemistry, proliferation/migration/invasion assays PloS one Low 27835650
2017 ZHX1 acts upstream of PUMA in a pro-apoptotic pathway in hepatocellular carcinoma cells; targeting ZHX1 with siRNA inhibits PUMA upregulation following miR-199a-3p overexpression, reversing effects on Bcl2, Bax, and cleaved caspase-3. siRNA transfection, Western blot, in vivo xenograft model American journal of translational research Medium 28559996
2023 Zhx1 directly interacts with hnRNPA1 via amino acid residues Thr111–His120 of its second zinc finger domain; the Zhx1/hnRNPA1 complex co-activates transcription of genes required for cardiac progenitor specification during cardiomyocyte differentiation from embryonic stem cells. Co-immunoprecipitation, domain-level interaction mapping, loss-of-function experiments in mouse and human ESC differentiation models, transcriptomics Cell death discovery High 37452012
2026 ZHX1 promotes transcription of mitochondrial ribosomal protein genes Mrps15 and Mrps21; ZHX1 overexpression or pharmacological activation with mithramycin ameliorates mitochondrial dysfunction in hypertensive heart disease, and combined silencing of Mrps15/Mrps21 abrogates ZHX1's cardioprotective effect. ZHX1 overexpression, mithramycin treatment, combined Mrps15/Mrps21 siRNA rescue experiment, mitochondrial respiration assay, membrane potential assay, in vivo L-NAME mouse model Biochemical pharmacology Medium 42162768

Source papers

Stage 0 corpus · 20 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2019 Blocking lncRNA MALAT1/miR-199a/ZHX1 Axis Inhibits Glioblastoma Proliferation and Progression. Molecular therapy. Nucleic acids 89 31648104
2014 MiR-199a-3p promotes gastric cancer progression by targeting ZHX1. FEBS letters 83 25448600
2018 lncRNA DLG1-AS1 Promotes Cell Proliferation by Competitively Binding with miR-107 and Up-Regulating ZHX1 Expression in Cervical Cancer. Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology 48 30231238
1996 zhx-1: a novel mouse homeodomain protein containing two zinc-fingers and five homeodomains. Biochemical and biophysical research communications 47 8713137
2016 ZHX1 Inhibits Gastric Cancer Cell Growth through Inducing Cell-Cycle Arrest and Apoptosis. Journal of Cancer 43 26722361
1999 Human ZHX1: cloning, chromosomal location, and interaction with transcription factor NF-Y. Biochemical and biophysical research communications 41 10441475
2007 Zinc-fingers and homeoboxes 1 (ZHX1) binds DNA methyltransferase (DNMT) 3B to enhance DNMT3B-mediated transcriptional repression. Biochemical and biophysical research communications 39 17303076
2017 MicroRNA-199a-3p inhibits tumorigenesis of hepatocellular carcinoma cells by targeting ZHX1/PUMA signal. American journal of translational research 37 28559996
2002 Functional analysis and the molecular dissection of zinc-fingers and homeoboxes 1 (ZHX1). Biochemical and biophysical research communications 34 12237128
2002 Rat zinc-fingers and homeoboxes 1 (ZHX1), a nuclear factor-YA-interacting nuclear protein, forms a homodimer. Gene 29 12062805
2003 Genomic structure and analysis of transcriptional regulation of the mouse zinc-fingers and homeoboxes 1 (ZHX1) gene. Gene 21 12527199
2020 Long non-coding RNA SNHG17 promotes proliferation, migration and invasion of glioma cells by regulating the miR-23b-3p/ZHX1 axis. The journal of gene medicine 15 32602607
2016 ZHX1 Promotes the Proliferation, Migration and Invasion of Cholangiocarcinoma Cells. PloS one 15 27835650
2013 The SUMOylation of zinc-fingers and homeoboxes 1 (ZHX1) by Ubc9 regulates its stability and transcriptional repression activity. Journal of cellular biochemistry 15 23686912
2007 BS69, a corepressor interacting with ZHX1, is a bifunctional transcription factor. Frontiers in bioscience : a journal and virtual library 14 17127430
2020 LncRNA LINC01140 Inhibits Glioma Cell Migration and Invasion via Modulation of miR-199a-3p/ZHX1 Axis. OncoTargets and therapy 13 32184618
2023 Cooperative regulation of Zhx1 and hnRNPA1 drives the cardiac progenitor-specific transcriptional activation during cardiomyocyte differentiation. Cell death discovery 5 37452012
2014 Solution NMR structures of homeodomains from human proteins ALX4, ZHX1, and CASP8AP2 contribute to the structural coverage of the Human Cancer Protein Interaction Network. Journal of structural and functional genomics 1 24941917
2026 Mrps15/Mrps21 induced by Zhx1 protects mice from hypertensive heart disease by restoring mitochondrial translation. Biochemical pharmacology 0 42162768
2024 LncRNA LINC01140 Inhibits Glioma Cell Migration and Invasion via Modulation of miR-199a-3p/ZHX1 Axis [Retraction]. OncoTargets and therapy 0 39011138

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