Affinage

SP5

Transcription factor Sp5 · UniProt Q6BEB4

Length
398 aa
Mass
42.0 kDa
Annotated
2026-04-28
44 papers in source corpus 17 papers cited in narrative 17 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

SP5 is a Wnt/β-catenin–responsive C2H2 zinc-finger transcription factor that functions as both a context-dependent transcriptional repressor and coactivator to shape Wnt signaling output during embryonic patterning, stem cell self-renewal, and ciliogenesis. SP5 binds GC-box elements shared with Sp1 and represses Sp1 target genes through its R1 domain–mediated interaction with the corepressor mSin3a, while also repressing Wnt target genes (including Wnt3 itself) to establish a negative feedback loop that restricts Wnt pathway activity (PMID:17090534, PMID:30659200, PMID:29044119). In a feed-forward capacity, SP5 binds GC boxes at Wnt target gene enhancers and interacts with TCF1/LEF1 to recruit β-catenin, amplifying select Wnt transcriptional responses, and directly activates the Nanog promoter to sustain embryonic stem cell self-renewal (PMID:26969725, PMID:28961274). Together with its paralog SP8, SP5 is required for primary cilia formation, neuromesodermal progenitor maintenance during axial elongation, and neural crest specification, and its promoter-binding activity can be enhanced by CPT1A-mediated succinylation (PMID:40875857, PMID:15797017, PMID:24038420, PMID:38494680).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 2000 High

    Establishing that SP5 is a GC-box–binding zinc-finger protein that genetically interacts with the mesodermal transcription factor Brachyury resolved the question of whether Sp5 has sequence-specific DNA-binding activity relevant to embryonic development.

    Evidence In vitro DNA binding assay plus compound-mutant mouse genetics (Sp5/Brachyury)

    PMID:11071760

    Open questions at the time
    • No identification of direct transcriptional targets beyond Brachyury promoter element
    • Activator vs. repressor function not yet distinguished
  2. 2005 High

    Placement of SP5 as a direct transcriptional target of the Wnt/β-catenin pathway—with identification of TCF/LEF binding sites in its promoter and β-catenin/Tcf4 response elements—answered how SP5 expression is regulated and linked it to canonical Wnt signaling across species.

    Evidence EMSA, luciferase reporters in human cells, and zebrafish epistasis (morpholino knockdown/overexpression rescue of wnt8 phenotype)

    PMID:15797017 PMID:16273202 PMID:16380080

    Open questions at the time
    • Genome-wide binding profile of SP5 not yet determined
    • Mechanism of transcriptional repression vs. activation not resolved
  3. 2006 High

    Identification of three independent repressor domains and the physical interaction of the R1 domain with corepressor mSin3a established how SP5 represses Sp1 target genes such as p21, resolving the mechanistic basis of its repressor function.

    Evidence Co-immunoprecipitation (Sp5–mSin3a), luciferase reporter domain mapping, conditional β-catenin activation in mouse CNS

    PMID:17090534

    Open questions at the time
    • Whether SP5 can also function as an activator was not addressed
    • Genome-wide repression targets unknown
  4. 2013 Medium

    Demonstrating that Sp5 operates downstream of both Wnt and FGF signaling to specify neural crest (regulating Msx1 and Pax3) extended its developmental role beyond mesoderm/neuroectoderm patterning.

    Evidence Morpholino knockdown and gain-of-function in Xenopus with Wnt/FGF epistasis

    PMID:24038420

    Open questions at the time
    • Direct promoter binding to Msx1/Pax3 not shown
    • Relative contribution of Sp5 vs. Sp8 in neural crest not dissected
  5. 2015 Medium

    Showing that Sp5 integrates LIF-Stat3 and Wnt/β-catenin inputs to maintain mouse ESC self-renewal and can revert epiblast stem cells to naïve pluripotency established SP5 as a convergence node for pluripotency signaling.

    Evidence Forced expression, knockdown, and signaling pathway inhibition in mESCs

    PMID:26598557

    Open questions at the time
    • Direct transcriptional targets mediating self-renewal not identified at this point
    • Mechanism of LIF-Stat3 input to Sp5 promoter not resolved
  6. 2016 High

    ChIP-seq and double-null genetics revealed that SP5 (with SP8) also acts as a transcriptional coactivator at Wnt target gene enhancers by binding GC boxes and recruiting β-catenin via TCF1/LEF1 interaction, resolving the apparent paradox of repressor and activator functions through a feed-forward circuit.

    Evidence ChIP-seq, co-immunoprecipitation, Sp5/Sp8 double-null mouse embryo phenotyping

    PMID:26969725

    Open questions at the time
    • Structural basis of SP5–TCF1/LEF1 interaction unknown
    • How context determines repressor vs. coactivator mode not defined
  7. 2017 High

    Two complementary studies resolved the dual output of SP5: direct binding to the Nanog promoter explained its stem-cell self-renewal function, while genome-wide profiling in SP5-mutant hPSCs demonstrated that SP5 represses previously WNT-activated genes, establishing SP5 as a WNT-induced negative feedback factor in stem cells.

    Evidence ChIP (Nanog promoter); ChIP-seq and RNA-seq in WT vs. SP5-mutant human pluripotent stem cells

    PMID:28961274 PMID:29044119

    Open questions at the time
    • Whether Nanog activation and global Wnt repression are independent or sequential is unclear
    • Chromatin remodeling mechanisms downstream of SP5 not characterized
  8. 2019 High

    Demonstrating that Hydra Sp5 directly represses the Wnt3 promoter and that its loss produces multi-headed animals provided deep evolutionary evidence for a conserved Sp5–Wnt negative feedback loop restricting organizer activity.

    Evidence RNAi knockdown in Hydra; luciferase reporter assay of Wnt3 promoter; conservation with zebrafish Sp5

    PMID:30659200

    Open questions at the time
    • Whether the Sp5–Wnt3 repression is direct in mammalian tissues not shown
    • Relative contribution of mSin3a vs. other corepressors in this feedback not tested
  9. 2023 Medium

    Identification of SP5 as a direct activator of BAMBI transcription in colorectal cancer, regulated by a circular RNA/miRNA axis, provided the first evidence of a noncoding RNA circuit controlling SP5 protein levels in a disease context.

    Evidence ChIP at BAMBI promoter; luciferase reporter; RNA pulldown and RIP for circSP5/miR-1249-3p; xenograft models

    PMID:37596430

    Open questions at the time
    • Whether the circSP5 regulatory axis operates in normal tissue is unknown
    • Functional consequence of BAMBI activation by SP5 on Wnt vs. TGF-β balance not dissected
  10. 2024 Medium

    Discovery that CPT1A succinylates SP5 to enhance its binding to the PDPK1 promoter revealed a previously unknown post-translational regulatory mechanism controlling SP5 transcriptional activity.

    Evidence Co-immunoprecipitation (CPT1A–SP5); ChIP (SP5 at PDPK1 promoter); luciferase reporter in prostate cancer cells

    PMID:38494680

    Open questions at the time
    • Specific succinylation sites on SP5 not mapped
    • Whether succinylation broadly modulates SP5 activity at other targets not tested
    • Independent confirmation pending
  11. 2025 High

    Conditional knockout of Sp5/Sp8 revealed an essential role in primary cilia formation and axial elongation: double mutants exhibit shorter/fewer cilia (causing situs inversus and hydrocephalus) and loss of neuromesodermal progenitors, establishing SP5 as a transcriptional regulator of ciliogenesis programs.

    Evidence Conditional knockout mouse genetics; multiomics transcriptome analysis; cilia imaging; SP8 gain-of-function in unciliated cells

    PMID:40875857

    Open questions at the time
    • Direct ciliogenesis target genes of SP5 (vs. SP8) not individually resolved
    • Whether SP5 alone is sufficient for cilia induction not tested

Open questions

Synthesis pass · forward-looking unresolved questions
  • Key unresolved questions include the structural basis of SP5's context-dependent switch between repressor and coactivator modes, the identity of the full post-translational modification landscape beyond succinylation, and whether SP5's ciliogenesis function is independent of its Wnt feedback role.
  • No crystal or cryo-EM structure of SP5 or SP5–TCF complex
  • Genome-wide mapping of SP5 succinylation-dependent targets not performed
  • Ciliogenesis function not mechanistically separated from Wnt feedback

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140110 transcription regulator activity 8 GO:0003677 DNA binding 5
Localization
GO:0005634 nucleus 4
Pathway
R-HSA-74160 Gene expression (Transcription) 8 R-HSA-162582 Signal Transduction 6 R-HSA-1266738 Developmental Biology 3 R-HSA-1852241 Organelle biogenesis and maintenance 1
Partners
CPT1ACTNNB1LEF1MSIN3ASP8TBXTTCF1

Evidence

Reading pass · 17 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2000 Mouse Sp5 protein binds to the GC box DNA motif (present in many gene promoters including Brachyury) via its C-terminal C2H2 zinc finger domain, as shown by in vitro DNA binding studies. Sp5 genetically interacts with Brachyury, since compound mutant mice (Sp5lacZ/Sp5lacZ, T/+) show enhancement of the T/+ phenotype. In vitro DNA binding assay; genetic epistasis (compound mutant mice) Developmental biology High 11071760
2005 Zebrafish sp5-like (and its paralog sp5) act downstream of Wnt8 in mesoderm and neuroectoderm patterning; sp5-like is a direct transcriptional target of Wnt/β-catenin signaling. Genetic epistasis shows combined knockdown of sp5 and sp5-like phenocopies loss of wnt8 (expansion of dorsal mesoderm), and overexpression of sp5-like partially rescues hindbrain patterning in wnt8 morphants. Zebrafish DNA microarray (target identification); morpholino knockdown; overexpression rescue; genetic epistasis Current biology : CB High 15797017
2006 Mouse Sp5 functions as a transcriptional repressor with three independent repressor domains (R1, R2, R3); the R1 domain mediates repression through direct physical interaction with the corepressor mSin3a. Sp5 shares DNA binding specificity with Sp1 and represses Sp1 target genes such as p21. The Sp5 gene promoter contains five TCF/LEF binding sites that mediate direct transcriptional activation by canonical Wnt/β-catenin signaling. Conditional Cre/loxP β-catenin activation in mouse CNS; luciferase reporter assays; co-immunoprecipitation (Sp5–mSin3a interaction); promoter deletion analysis The Journal of biological chemistry High 17090534
2005 Human SP5 is a direct transcriptional target of the β-catenin/Tcf4 complex; an electromobility-shift assay and reporter assays identified the DNA element between −285 and −279 in the SP5 5′ flanking region as the β-catenin/Tcf4 binding site. SP5 expression is down-regulated after depletion of β-catenin by wild-type APC transduction in SW480 cells. cDNA microarray; electromobility-shift assay (EMSA); luciferase reporter assay; APC transduction International journal of oncology Medium 16273202
2005 Human SP5 contains a transcriptional activation domain (N-terminal), an intrinsic repressive element, and a C-terminal synergistic domain, as determined by Gal4-Sp5 fusion protein assays. Overexpression of SP5 in MCF-7 cells promotes cell growth and regulates genes associated with tumorigenesis and Wnt/β-catenin signaling (e.g., p21WAF1, BAMBI, SIX1). Gal4 fusion transcriptional domain mapping; inducible gene expression + microarray; cell growth assay Biochemical and biophysical research communications Medium 16380080
2013 Xenopus Sp5 functions as an early regulator of neural crest (NC) specification downstream of Wnt/β-catenin and FGF signaling. Knockdown of Sp5 causes defects in craniofacial cartilage, pigmentation, and dorsal fin, and reduces NC marker expression in the neural fold. Sp5 regulates NPB specifiers Msx1 and Pax3, and co-expression of Sp5 rescues NC markers when Wnt or FGF signaling is blocked. Morpholino knockdown; gain- and loss-of-function; epistasis with Wnt/β-catenin and FGF pathway inhibition; in situ hybridization Developmental dynamics : an official publication of the American Association of Anatomists Medium 24038420
2015 Sp5 acts as a convergence point of LIF-Stat3 and Wnt/β-catenin signaling to promote mouse embryonic stem cell (mESC) self-renewal. Forced Sp5 expression reproduces effects of LIF-Stat3 signaling and maintains undifferentiated mESCs; Sp5 can convert mouse epiblast stem cells to naïve pluripotent state. Forced expression; knockdown; signaling pathway inhibition; pluripotency assays in mESCs Journal of cell science Medium 26598557
2016 SP5 (and SP8) function as transcriptional coactivators in the Wnt/β-catenin pathway. They bind directly to GC boxes in Wnt target gene enhancers and interact with chromatin-bound TCF1/LEF1 to facilitate recruitment of β-catenin to target gene enhancers, acting in a feed-forward loop because Sp5 is itself a direct Wnt target. ChIP in mouse embryos and differentiating ES cells; co-immunoprecipitation; Sp5/Sp8 double null mutant mouse embryo phenotyping; ChIP-seq Proceedings of the National Academy of Sciences of the United States of America High 26969725
2017 SP5 directly binds to the Nanog promoter (shown by ChIP) and induces Nanog expression to mediate mESC self-renewal. The zinc finger domains of Sp5 are required for this self-renewal-promoting function. Knockdown of Nanog eliminates the self-renewal-promoting ability of Sp5. Chromatin immunoprecipitation (ChIP); overexpression; knockdown/knockout; mESC self-renewal assays PloS one Medium 28961274
2017 SP5 acts to terminate/diminish Wnt-induced transcriptional programs in human pluripotent stem cells. Integration of SP5 genome-wide binding (ChIP-seq) with gene expression profiles of wild-type and SP5 mutant hPSCs shows SP5 represses genes previously activated by WNT signaling. SP5 activation by WNT is most robust in developmentally potent (stem) cells. ChIP-seq; RNA-seq of wild-type vs. SP5 mutant hPSCs; WNT pathway activation experiments Nature communications High 29044119
2019 Hydra Sp5 functions as a transcriptional repressor of Wnt3 and is positively regulated by Wnt/β-catenin signaling, forming a negative feedback loop that restricts head organizer activity. Both Hydra and zebrafish Sp5 repress Wnt3 promoter activity in reporter assays; Hydra Sp5 also activates its own expression likely via β-catenin/TCF interaction. Knockdown of Sp5 in Hydra produces a robust multi-headed phenotype. RNAi knockdown; luciferase reporter assay (Wnt3 promoter); genetic epistasis; promoter analysis Nature communications High 30659200
2018 Sp5 inhibits proliferation of HCT116 colon cancer cells by upregulating transcription of the cell cycle inhibitor p27. Sp5 overexpression in HCT116 cells; cell proliferation assay; p27 expression analysis Oncology letters Low 29456745
2024 CPT1A acts as a succinyltransferase that promotes succinylation of SP5, which strengthens the binding of SP5 to the PDPK1 promoter, thereby activating PDPK1 transcription and downstream AKT/mTOR signaling in prostate cancer cells. Co-immunoprecipitation (CPT1A–SP5); ChIP (SP5 binding to PDPK1 promoter); luciferase reporter assay; Seahorse glycolysis assay; CCK-8 viability assay Cancer biology & therapy Medium 38494680
2025 SP5 (and SP8) act as transcription factors required for primary cilia formation; in Sp5/Sp8 double-mutant mouse embryos, primary and motile cilia are shorter and reduced in number, contributing to situs inversus and hydrocephalus. SP8 expression alone is sufficient to induce primary cilia in unciliated cells. Conditional knockout mouse genetics; multiomics (transcriptome comparison of ciliated vs. unciliated cells); stem cell overexpression of SP8; cilia imaging Science (New York, N.Y.) High 40875857
2025 SP5 binds to the SERPING1 gene promoter and activates its transcription, placing SP5 as an upstream regulator of the SERPING1/TSC2/mTOR axis that suppresses lung adenocarcinoma progression. ChIP; luciferase reporter assay; in vitro and in vivo proliferation/migration/invasion assays Cell death & disease Medium 39962118
2025 SP5 and SP8 are essential regulators of neuromesodermal progenitor (NMC) maintenance during axial elongation. Mechanistically, Sp5/8 cooperate with Tbxt, Tcf7, and Cdx2 to sustain the Wnt3a/Fgf autoregulatory loop by binding a novel enhancer essential for Wnt3a expression. Sp5/8 regulate the dynamic exchange of activating and repressive Tcf complexes at Wnt-responsive enhancers. Conditional mouse genetics; ChIP-seq; enhancer deletion; multiomics transcriptome analysis; stem cell differentiation models bioRxivpreprint Medium bio_10.1101_2025.06.03.657492
2023 CircSP5 (has_circ_0057010) functions as a miR-1249-3p sponge to upregulate SP5 protein, which then directly activates BAMBI transcription (shown by ChIP and luciferase assay), promoting colorectal cancer liver metastasis via EMT. RNA pulldown; RIP; luciferase reporter assay; ChIP (SP5 at BAMBI promoter); wound healing and transwell assays; xenograft models Functional & integrative genomics Medium 37596430

Source papers

Stage 0 corpus · 44 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
1987 Low molecular weight human pulmonary surfactant protein (SP5): isolation, characterization, and cDNA and amino acid sequences. Proceedings of the National Academy of Sciences of the United States of America 193 3479771
2005 The Sp1-related transcription factors sp5 and sp5-like act downstream of Wnt/beta-catenin signaling in mesoderm and neuroectoderm patterning. Current biology : CB 180 15797017
1991 Characterization of Sp-5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole- 3',5'-monophosphorothioate (Sp-5,6-DCl-cBiMPS) as a potent and specific activator of cyclic-AMP-dependent protein kinase in cell extracts and intact cells. The Biochemical journal 144 1659381
2000 Sp5, a new member of the Sp1 family, is dynamically expressed during development and genetically interacts with Brachyury. Developmental biology 108 11071760
2019 An evolutionarily-conserved Wnt3/β-catenin/Sp5 feedback loop restricts head organizer activity in Hydra. Nature communications 73 30659200
2006 Wnt-mediated down-regulation of Sp1 target genes by a transcriptional repressor Sp5. The Journal of biological chemistry 68 17090534
2017 The WNT target SP5 negatively regulates WNT transcriptional programs in human pluripotent stem cells. Nature communications 58 29044119
2008 SP5: improving protein fold recognition by using torsion angle profiles and profile-based gap penalty model. PloS one 58 18523556
2016 Sp5 and Sp8 recruit β-catenin and Tcf1-Lef1 to select enhancers to activate Wnt target gene transcription. Proceedings of the National Academy of Sciences of the United States of America 53 26969725
2015 Wnt/β-catenin and LIF-Stat3 signaling pathways converge on Sp5 to promote mouse embryonic stem cell self-renewal. Journal of cell science 53 26598557
2001 The novel transcription factor gene Sp5 exhibits a dynamic and highly restricted expression pattern during mouse embryogenesis. Mechanisms of development 46 11231070
2018 Genome Analysis of Fimbriiglobus ruber SP5T, a Planctomycete with Confirmed Chitinolytic Capability. Applied and environmental microbiology 45 29374042
2005 Identification of SP5 as a downstream gene of the beta-catenin/Tcf pathway and its enhanced expression in human colon cancer. International journal of oncology 39 16273202
2005 Elevated expression and potential roles of human Sp5, a member of Sp transcription factor family, in human cancers. Biochemical and biophysical research communications 39 16380080
2019 A small set of conserved genes, including sp5 and Hox, are activated by Wnt signaling in the posterior of planarians and acoels. PLoS genetics 34 31626630
1994 Studies on intrachromosomal recombination in SP5/V79 Chinese hamster cells upon exposure to different agents related to carcinogenesis. Carcinogenesis 34 7955071
2022 Genomic Insight Into Lacticaseibacillus paracasei SP5, Reveals Genes and Gene Clusters of Probiotic Interest and Biotechnological Potential. Frontiers in microbiology 25 35783439
2013 Role of Sp5 as an essential early regulator of neural crest specification in xenopus. Developmental dynamics : an official publication of the American Association of Anatomists 21 24038420
2024 CPT1A mediates the succinylation of SP5 which activates transcription of PDPK1 to promote the viability and glycolysis of prostate cancer cells. Cancer biology & therapy 20 38494680
2015 D-SP5 Peptide-Modified Highly Branched Polyethylenimine for Gene Therapy of Gastric Adenocarcinoma. Bioconjugate chemistry 20 26052814
2011 Analysis of the surface proteins of Acidithiobacillus ferrooxidans strain SP5/1 and the new, pyrite-oxidizing Acidithiobacillus isolate HV2/2, and their possible involvement in pyrite oxidation. Archives of microbiology 19 21698546
1992 Reversion of the hprt mutant clone SP5 by intrachromosomal recombination. Carcinogenesis 19 1576714
2022 Investigating the plant growth promoting and biocontrol potentiality of endophytic Streptomyces SP. SP5 against early blight in Solanum lycopersicum seedlings. BMC microbiology 16 36447141
1994 cDNA cloning and expression of Xenopus sperm-specific basic nuclear protein 5 (SP5) gene. Molecular reproduction and development 11 8011321
2017 Sp5 induces the expression of Nanog to maintain mouse embryonic stem cell self-renewal. PloS one 10 28961274
2017 Amphioxus Sp5 is a member of a conserved Specificity Protein complement and is modulated by Wnt/β-catenin signalling. The International journal of developmental biology 10 29319119
2018 Sp5 negatively regulates the proliferation of HCT116 cells by upregulating the transcription of p27. Oncology letters 8 29456745
2016 In vitro cytotoxicity and antimicrobial activity of Talaromyces flavus SP5 inhabited in the marine sediment of Southern Coast of India. Chinese journal of natural medicines 7 28262118
2023 Evolutionarily conserved Wnt/Sp5 signaling is critical for anterior-posterior axis patterning in sea urchin embryos. iScience 6 38179064
2021 The hokW-sokW Locus Encodes a Type I Toxin-Antitoxin System That Facilitates the Release of Lysogenic Sp5 Phage in Enterohemorrhagic Escherichia coli O157. Toxins 6 34822580
2015 A recombined fusion protein SP5.2/tTF induce thrombosis in tumor blood vessel. Neoplasma 6 25997964
1993 The effect of splenopentin (DA SP-5) on in vitro myelopoiesis and on AZT-induced bone marrow toxicity. International journal of immunopharmacology 6 8505137
2024 The Wnt/β-catenin/TCF/Sp5/Zic4 Gene Network That Regulates Head Organizer Activity in Hydra Is Differentially Regulated in Epidermis and Gastrodermis. Biomedicines 5 38927481
1997 Upregulation of HLA class-I gene transcription in K562 cells by analogs of splenopentin (SP-5). Biochemistry and molecular biology international 5 9090459
2025 Transcription factors SP5 and SP8 drive primary cilia formation in mammalian embryos. Science (New York, N.Y.) 4 40875857
2025 Organizer formation, organizer maintenance and epithelial cell plasticity in Hydra: Role of the Wnt3/β-catenin/TCF/Sp5/Zic4 gene network. Cells & development 3 39929422
2025 WNT inhibitor SP5-mediated SERPING1 suppresses lung adenocarcinoma progression via TSC2/mTOR pathway. Cell death & disease 3 39962118
2024 Divergent functions of the evolutionarily conserved, yet seemingly dispensable, Wnt target, sp5. Differentiation; research in biological diversity 3 39675112
2019 Xenopus laevis FGF16 activates the expression of genes coding for the transcription factors Sp5 and Sp5l. The International journal of developmental biology 3 32149373
2023 Circular RNA circSP5 promotes liver metastasis of colorectal cancer via SP5-mediated BAMBI transcription. Functional & integrative genomics 2 37596430
1989 Prevention of graft-vs-host reaction induced immunodeficiency by treatment with splenopentin (DAc-SP5). Allergie und Immunologie 1 2624251
2025 Transcription factors SP5 and SP8 drive primary cilia formation. bioRxiv : the preprint server for biology 0 40501818
2010 [Construction of eukaryotic vector of small hairpin interfering RNA against NYD-SP5]. Zhonghua nan ke xue = National journal of andrology 0 20684327
1996 Relative amounts of basic nuclear proteins SP4 and SP5 in Xenopus laevis sperm correlate with gene copy number. Development, growth & differentiation 0 37281109