sox2

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0000122 negative regulation of transcription by RNA polymerase II	IBA GO_REF:0000033	KEEP AS NON CORE	Summary: Negative regulation of RNA polymerase II transcription, inherited from the SoxB1/SoxB2 node (PTN008496689) whose donors include mouse Sox1/2/3/21, Drosophila SoxNeuro and zebrafish sox paralogs. Reason: SoxB1 proteins can repress as well as activate (mammalian SOX2 repression is SUMO-dependent), and in the frog embryo SoxB1 gain of function at the neural plate border lowers foxd3 and snail2 expression. No repressed direct target of frog Sox2 has been mapped, and the frog evidence for repression is gain-of-function only. The node placement is sound and the target sits inside the clade, so the term is retained, but Sox2 is predominantly an activator and repression is a context-dependent, non-core facet. Supporting Evidence: PMID:30144418 Interestingly, we found that inducing SoxB1 activity at the neural plate border at these stages led to down-regulation of neural crest factors Foxd3 and Snail2 (Figure 3B, S1C).
GO:0000122 negative regulation of transcription by RNA polymerase II	IEA GO_REF:0000118	KEEP AS NON CORE	Summary: TreeGrafter (PTN008941903) transfer of negative regulation of RNA polymerase II transcription. Reason: Same inference as the IBA row, delivered by TreeGrafter; retained as non-core for the reasons given there (repression is context-dependent; frog evidence is SoxB1 gain of function at the border). Supporting Evidence: PMID:30144418 Interestingly, we found that inducing SoxB1 activity at the neural plate border at these stages led to down-regulation of neural crest factors Foxd3 and Snail2 (Figure 3B, S1C).
GO:0000978 RNA polymerase II cis-regulatory region sequence-specific DNA binding	IBA GO_REF:0000033	ACCEPT	Summary: RNA polymerase II cis-regulatory region sequence-specific DNA binding, inherited at the Sox family node PTN000030384. Reason: Sox2 has a canonical HMG box (residues 37-105), and endogenous frog Sox2 occupies the conserved CNS1 enhancer upstream of the Rax promoter together with Otx2. Sequence-specific binding of Pol II cis-regulatory elements is the core molecular activity of the protein. Supporting Evidence: file:XENLA/sox2/sox2-uniprot.txt /note="HMG box" PMID:18385377 We revealed that endogenous Otx2 and Sox2 proteins bound to the conserved noncoding sequence (CNS1) located approximately 2 kb upstream of the Rax promoter.
GO:0000978 RNA polymerase II cis-regulatory region sequence-specific DNA binding	IEA GO_REF:0000118	ACCEPT	Summary: TreeGrafter transfer of RNA polymerase II cis-regulatory region sequence-specific DNA binding. Reason: Consistent with the IBA row and with frog Sox2 occupancy of the Rax CNS1 enhancer. Supporting Evidence: PMID:18385377 We revealed that endogenous Otx2 and Sox2 proteins bound to the conserved noncoding sequence (CNS1) located approximately 2 kb upstream of the Rax promoter.
GO:0001228 DNA-binding transcription activator activity, RNA polymerase II-specific	IBA GO_REF:0000033	ACCEPT	Summary: DNA-binding transcription activator activity, RNA polymerase II-specific, inherited at PTN000030384. Reason: Frog Sox2 binds the Rax CNS1 enhancer and synergistically activates it with Otx2; the protein carries a C-terminal 9aaTAD transactivation motif; and Sox2/SoxB1 activity is required for neural gene expression in ectoderm. This is the best-supported molecular function and the activity through which Sox2 confers neural competence. Supporting Evidence: PMID:18385377 We revealed that endogenous Otx2 and Sox2 proteins bound to the conserved noncoding sequence (CNS1) located approximately 2 kb upstream of the Rax promoter. PMID:18385377 Reporter assays showed that Otx2 and Sox2 synergistically activated transcription via CNS1. file:XENLA/sox2/sox2-uniprot.txt The 9aaTAD motif is a transactivation domain present in a large number of yeast and animal transcription factors.
GO:0001228 DNA-binding transcription activator activity, RNA polymerase II-specific	IEA GO_REF:0000118	ACCEPT	Summary: TreeGrafter transfer of RNA polymerase II-specific activator activity. Reason: Consistent with the IBA row and with the Rax CNS1 reporter evidence. Supporting Evidence: PMID:18385377 Reporter assays showed that Otx2 and Sox2 synergistically activated transcription via CNS1.
GO:0005515 protein binding	IPI PMID:18385377 Molecular links among the causative genes for ocular malform...	MODIFY	Summary: Protein binding with Otx2 (otx2-a, Q91813) from Danno et al. 2008 (co-immunoprecipitation; IntAct). Reason: Generic protein binding is uninformative. The paper shows that Sox2 physically binds Otx2, a homeodomain DNA-binding transcription factor, and that the two co-occupy the Rax CNS1 enhancer and synergistically activate it; Sox2-missense mutations from ocular disorders affect the interaction. The informative function is binding to a DNA-binding transcription factor partner (GO:0140297), the term mouse Sox2 carries by IPI. The cached record is abstract-only, but the abstract states the interaction and its functional context directly. Proposed replacements: DNA-binding transcription factor binding Supporting Evidence: PMID:18385377 Furthermore, the Otx2 and Sox2 proteins physically interacted with each other PMID:18385377 Reporter assays showed that Otx2 and Sox2 synergistically activated transcription via CNS1.
GO:0005634 nucleus	IBA GO_REF:0000033	ACCEPT	Summary: Nucleus, inherited at PTN000030384 from many Sox family members. Reason: Sox2 is a nuclear HMG-box transcription factor; UniProt places it in the nucleus, and nuclear localisation is required for its activity. Supporting Evidence: file:XENLA/sox2/sox2-uniprot.txt SUBCELLULAR LOCATION: Nucleus file:XENLA/sox2/sox2-deep-research-falcon.md Its operative compartment is therefore the nucleus of expressing cells, rather than the extracellular space.
GO:0005634 nucleus	IEA GO_REF:0000120	ACCEPT	Summary: Nucleus from UniProt subcellular location mapping and TreeGrafter. Reason: Correct; see IBA row. Supporting Evidence: file:XENLA/sox2/sox2-uniprot.txt SUBCELLULAR LOCATION: Nucleus
GO:0005634 nucleus	ISS GO_REF:0000024	ACCEPT	Summary: Nucleus by similarity to chicken Sox2 (P48430). Reason: Correct; consistent with all other evidence for nuclear localisation. Supporting Evidence: file:XENLA/sox2/sox2-uniprot.txt SUBCELLULAR LOCATION: Nucleus
GO:0005737 cytoplasm	ISS GO_REF:0000024	KEEP AS NON CORE	Summary: Cytoplasm by similarity to mouse Sox2 (P48432). Reason: Mammalian Sox2 can be cytoplasmic in some cell types (nucleocytoplasmic shuttling, regulated export), so the transfer is plausible, but no frog study places Sox2 in the cytoplasm and its function is exercised in the nucleus. Retained as a non-core location. Supporting Evidence: file:XENLA/sox2/sox2-deep-research-falcon.md Its operative compartment is therefore the nucleus of expressing cells, rather than the extracellular space.
GO:0006355 regulation of DNA-templated transcription	IEA GO_REF:0000002	ACCEPT	Summary: Regulation of DNA-templated transcription from the InterPro SOX family signature (IPR022097). Reason: Correct but general; the more precise RNA polymerase II terms (GO:0045944, GO:0000122) are also present. Supporting Evidence: PMID:18385377 Reporter assays showed that Otx2 and Sox2 synergistically activated transcription via CNS1.
GO:0007399 nervous system development	IMP PMID:10648237 Requirement of Sox2-mediated signaling for differentiation o...	ACCEPT	Summary: Nervous system development, from Kishi et al. 2000: dominant-negative Sox2 (including a hormone-inducible version) blocks neural differentiation of animal caps and suppresses N-CAM and regional neural markers in embryos. Reason: This is the central frog role of Sox2: it is required for early neuroectoderm to consolidate neural identity, from late blastula onward. A dominant-negative construct may also block Sox3 (the authors write of "Sox2-class genes"), and later combined Sox2/Sox3 morpholino data confirm the SoxB1 requirement for neural induction, so the attribution is to SoxB1 activity in which Sox2 participates. Nervous system development is broad but accurate; core. Supporting Evidence: PMID:10648237 Microinjection of dominant-negative forms of Sox2 (dnSox2) mRNA inhibits neural differentiation of animal caps caused by attenuation of BMP signals. PMID:10648237 These data suggest that Sox2-class genes are essential for early neuroectoderm cells to consolidate their neural identity during secondary steps of neural differentiation. PMID:30144418 We first showed that morpholino-mediated depletion of Sox2 and Sox3 prevented chordin-mediated neural induction (Figure 6A–B).
GO:0007399 nervous system development	IMP PMID:9435279 Xenopus Zic-related-1 and Sox-2, two factors induced by chor...	ACCEPT	Summary: Nervous system development, from Mizuseki et al. 1998: Sox2 is an early Chordin-induced, BMP4-suppressed neuroectoderm gene that makes ectoderm responsive to FGF to initiate neural induction. Reason: Sox2 is not sufficient for neural differentiation alone but synergises with FGF to neuralise ectoderm, i.e. it confers neural competence. The cached record is abstract-only; the curator saw the full text, and the role is well established by the independent dnSox2 and Sox2/Sox3 morpholino studies. Core. Supporting Evidence: PMID:9435279 Sox-2 alone is not sufficient to cause neural differentiation, but can work synergistically with FGF signaling to initiate neural induction. PMID:9435279 Sox-2 makes the ectoderm responsive to extracellular signals file:XENLA/sox2/sox2-uniprot.txt participating in the differentiation of embryonic neuroectodermal cells into neural tissues by making the ectodermal cells responsive to FGF-neuralizing signals
GO:0007420 brain development	IBA GO_REF:0000033	KEEP AS NON CORE	Summary: Brain development, inherited at the SoxB node PTN008496689 (mouse Sox1/2/21, human SOX2, Drosophila SoxN, zebrafish sox paralogs). Reason: Sox2 is expressed throughout the developing frog brain and eye and its neural-progenitor role is conserved, so the inheritance is sound. The term is an anatomical-system-level consequence of its general neural progenitor role rather than a specific frog brain function, and is kept as non-core alongside the more informative neural induction and retinal terms. Supporting Evidence: file:XENLA/sox2/sox2-uniprot.txt At stage 23 (early tailbud), expressed in the primitive brain and optic vesicle, with expression high in the anterior neural tube.
GO:0007420 brain development	IEA GO_REF:0000118	KEEP AS NON CORE	Summary: TreeGrafter transfer of brain development. Reason: As for the IBA row. Supporting Evidence: file:XENLA/sox2/sox2-uniprot.txt At stage 23 (early tailbud), expressed in the primitive brain and optic vesicle, with expression high in the anterior neural tube.
GO:0030154 cell differentiation	IEA GO_REF:0000118	KEEP AS NON CORE	Summary: Cell differentiation from TreeGrafter. Reason: True but uninformative: Sox2 regulates neural progenitor competence and the timing of neuronal versus glial differentiation, captured by GO:0030182 and the proposed GO:0045665. Retained as a high-level non-core term. Supporting Evidence: PMID:19736324 We now report that Wnt and Sox2 inhibit neural differentiation through Notch activation.
GO:0030182 neuron differentiation	IBA GO_REF:0000033	ACCEPT	Summary: Neuron differentiation, inherited at PTN008496689 from SoxB proteins in fly, worm, fish and mammals. Reason: SoxB1 proteins are ancient regulators of neural progenitors and the node is well placed. In frog, Sox2 is required for proneural gene onset in the retina and for neural differentiation of ectoderm, and later restrains terminal neuronal differentiation through Notch until it is switched off. Involvement in neuron differentiation (both enabling competence and controlling timing) is therefore well supported; core, with GO:0045665 added for the restraining role. Supporting Evidence: PMID:15820691 Blocking Sox2 function mimics these effects. PMID:19736324 We now report that Wnt and Sox2 inhibit neural differentiation through Notch activation. PMID:19736324 For neuronal differentiation to proceed, Sox2 must also be switched off to relieve the inhibition of proneural activity.
GO:0030182 neuron differentiation	IEA GO_REF:0000118	ACCEPT	Summary: TreeGrafter transfer of neuron differentiation. Reason: As for the IBA row. Supporting Evidence: PMID:15820691 Blocking Sox2 function mimics these effects.
GO:0043565 sequence-specific DNA binding	ISS GO_REF:0000024	ACCEPT	Summary: Sequence-specific DNA binding by similarity to chicken Sox2 (P48430). Reason: Correct; less specific than GO:0000978 but accurate for an HMG-box factor that binds the Rax CNS1 enhancer. Supporting Evidence: file:XENLA/sox2/sox2-uniprot.txt /note="HMG box" PMID:18385377 We revealed that endogenous Otx2 and Sox2 proteins bound to the conserved noncoding sequence (CNS1) located approximately 2 kb upstream of the Rax promoter.
GO:0045893 positive regulation of DNA-templated transcription	ISS GO_REF:0000024	ACCEPT	Summary: Positive regulation of DNA-templated transcription by similarity to chicken Sox2 (P48430). Reason: Correct; parent of GO:0045944, supported by Rax CNS1 activation. Supporting Evidence: PMID:18385377 Reporter assays showed that Otx2 and Sox2 synergistically activated transcription via CNS1.
GO:0045944 positive regulation of transcription by RNA polymerase II	IBA GO_REF:0000033	ACCEPT	Summary: Positive regulation of RNA polymerase II transcription, inherited at PTN000030384. Reason: Sox2 activates the Rax CNS1 enhancer with Otx2 and is required for neural gene expression in ectoderm; this is the process counterpart of its core activator function. Supporting Evidence: PMID:18385377 Reporter assays showed that Otx2 and Sox2 synergistically activated transcription via CNS1. file:XENLA/sox2/sox2-uniprot.txt The 9aaTAD motif is a transactivation domain present in a large number of yeast and animal transcription factors.
GO:0045944 positive regulation of transcription by RNA polymerase II	IEA GO_REF:0000118	ACCEPT	Summary: TreeGrafter transfer of positive regulation of RNA polymerase II transcription. Reason: As for the IBA row. Supporting Evidence: PMID:18385377 Reporter assays showed that Otx2 and Sox2 synergistically activated transcription via CNS1.
GO:0045944 positive regulation of transcription by RNA polymerase II	ISS GO_REF:0000024	ACCEPT	Summary: Positive regulation of RNA polymerase II transcription by similarity to chicken Sox2 (P48430). Reason: As for the IBA row. Supporting Evidence: PMID:18385377 Reporter assays showed that Otx2 and Sox2 synergistically activated transcription via CNS1.
GO:0160108 animal gross anatomical part developmental process	IEA GO_REF:0000117	KEEP AS NON CORE	Summary: Animal gross anatomical part developmental process, from an ARBA machine-learning rule. Reason: A very high-level grouping term; it is true (Sox2 acts in brain, eye and spinal cord development) but adds no information beyond nervous system development and retina development. Kept as non-core, as for other ARBA rows of this term. Supporting Evidence: file:XENLA/sox2/sox2-uniprot.txt participating in the differentiation of embryonic neuroectodermal cells into neural tissues by making the ectodermal cells responsive to FGF-neuralizing signals
GO:0045665 negative regulation of neuron differentiation	IMP PMID:19736324 A directional Wnt/beta-catenin-Sox2-proneural pathway regula...	NEW	Summary: Proposed: Sox2 restrains neuronal differentiation of retinal progenitors through Notch, downstream of Wnt/beta-catenin. Reason: Agathocleous et al. 2009 show that sustained Sox2 blocks retinal neurogenesis cell-autonomously and that the block requires Notch (Su(H)DBM abolishes it); Sox2 must be switched off by the proneural factors for neurons to form. Sox2 does the work as the transcription factor that keeps Notch active and opposes proneural activity, so the participation test is met. Comparator (QuickGO 2026-10-07): mouse Sox2 carries GO:0045665 by IDA (PMID:16631155) and human SOX2 by ISS, so frog lacks only the curation. The evidence is gain-of-function plus epistasis; it complements, not replaces, the competence role. Supporting Evidence: PMID:19736324 We now report that Wnt and Sox2 inhibit neural differentiation through Notch activation. PMID:19736324 For neuronal differentiation to proceed, Sox2 must also be switched off to relieve the inhibition of proneural activity.
GO:0060041 retina development in camera-type eye	IMP PMID:15820691 Frizzled 5 signaling governs the neural potential of progeni...	NEW	Summary: Proposed: Sox2 is required in retinal progenitors for neural potential, downstream of Frizzled-5/Wnt. Reason: Van Raay et al. 2005 show that Xfz5/Wnt maintains Sox2 in the optic vesicle and that blocking Sox2 reproduces the Xfz5 loss phenotype (reduced proliferation, no proneural onset, non-neural bias of progenitors), with Sox2 rescuing Xfz5 loss. Sox2 is the transcription factor that confers neural competence on retinal progenitors, so it performs part of retinal development rather than merely being needed for it. Kept non-core relative to the general neural progenitor role. Abstract-only in cache; the abstract states the Sox2 loss-of-function result directly. Supporting Evidence: PMID:15820691 We show that the frizzled (Fz) transmembrane receptor Xfz5 selectively governs neural potential in the developing Xenopus retina by regulating the expression of Sox2. PMID:15820691 Blocking Sox2 function mimics these effects.

Gene Description

Existing Annotations Review

Core Functions

Nuclear SoxB1 HMG-box transcriptional activator that binds Sox motifs in RNA polymerase II enhancers and cooperates with partner DNA-binding factors (Otx2 at the Rax CNS1 enhancer).

Neural competence of ectoderm: induced by BMP antagonism at gastrulation, Sox2 (with Sox3) makes ectoderm responsive to FGF neuralising signals and is required for neural induction and for consolidation of neural identity in the neural plate.

Neural progenitor state in the retina: maintained by Frizzled-5/Wnt, Sox2 confers proneural competence, then restrains neuronal differentiation through Notch (favouring Muller glia) until proneural factors switch it off.

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