Xenopus laevis c-Ets-1-A (Ets1a; the S-subgenome ets1 homeolog) is an ETS-family sequence-specific transcription factor with an N-terminal pointed (PNT/SAM) domain, a transactivation region and a C-terminal ETS winged helix-turn-helix DNA-binding domain whose DNA binding is autoinhibited by flanking helices. It acts in the nucleus, mainly as an activator of RNA polymerase II target genes, but can also repress targets by recruiting HDAC1 (e.g. the BMP-responsive id3 promoter). In the embryo ets1 is expressed in premigratory and migrating neural crest, especially cranial and cardiac crest, and in hemangioblastic, endothelial and endocardial precursors. Within the neural crest gene regulatory network it belongs to the crest-specifier layer rather than the neural plate border layer: in amniotes it is switched on after the border genes, downstream of Tfap2b, as part of a cranial-identity circuit with Sox8 and Tfap2b, and it directly activates the cranial Sox10E2 enhancer. In frog its loss impairs neural crest delamination, collective migration and stream segregation rather than initial crest induction, and it is separately required in heart mesoderm for endocardium and heart-tube formation. Expression of Ets1 in premigratory/migratory crest is absent in lamprey but present in skate, so its recruitment into the crest programme appears to be a gnathostome innovation.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000981 DNA-binding transcription factor activity, RNA polymerase II-specific | IBA GO_REF:0000033 | ACCEPT | Summary: Sequence-specific RNA polymerase II DNA-binding transcription factor activity, inherited from the ETS family PAINT node. Reason: P18755 has a canonical ETS DNA-binding domain and the ETS-family function as an RNA polymerase II sequence-specific transcription factor is conserved and experimentally established for the vertebrate orthologs (e.g. direct binding of chick Ets1 to the cranial Sox10E2 enhancer; Xenopus Ets1a occupancy of the id3 promoter). Correct core molecular function at an appropriate level. Supporting Evidence: PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. file:XENLA/ets1-a/ets1-a-deep-research-falcon.md FLAG-tagged frog Ets1a occupied its predicted binding region in embryo chromatin-immunoprecipitation assays. |
| GO:0000981 DNA-binding transcription factor activity, RNA polymerase II-specific | IEA GO_REF:0000118 | ACCEPT | Summary: TreeGrafter electronic transfer of RNA polymerase II-specific DNA-binding transcription factor activity. Reason: Same assertion as the IBA, consistent with domain architecture and ortholog experiments. Supporting Evidence: PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. |
| GO:0003677 DNA binding | ISS GO_REF:0000024 | MODIFY | Summary: DNA binding, transferred from mouse Ets1 (P27577), where the autoinhibited ETS domain/DNA interaction was characterised. Reason: Correct but uninformative. Ets1 binds specific ETS motifs (GGA core) in cis-regulatory regions of RNA polymerase II genes; ortholog ChIP/gel-shift data show direct binding to the Sox10E2 enhancer and frog Ets1a occupies the id3 promoter. Replace with the cis-regulatory sequence-specific term. Proposed replacements: RNA polymerase II cis-regulatory region sequence-specific DNA binding Supporting Evidence: PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. file:XENLA/ets1-a/ets1-a-deep-research-falcon.md FLAG-tagged frog Ets1a occupied its predicted binding region in embryo chromatin-immunoprecipitation assays. |
| GO:0003700 DNA-binding transcription factor activity | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro-based mapping of DNA-binding transcription factor activity from ETS domain signatures. Reason: Correct, if more general than the RNA polymerase II-specific term; acceptable for an electronic mapping. Supporting Evidence: PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. |
| GO:0003700 DNA-binding transcription factor activity | ISS GO_REF:0000024 | ACCEPT | Summary: DNA-binding transcription factor activity transferred from human ETS1 (P14921). Reason: Correct general statement of the core activity; the more precise activator term is proposed separately as NEW. Supporting Evidence: PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. PMID:26198637 Mechanistically, we found that Ets1 binds to id3 promoter as well as histone deacetylase 1, suggesting that Ets1 recruits histone deacetylase 1 to the promoter of id3, thereby inducing histone deacetylation of the id3 promoter. |
| GO:0005634 nucleus | IBA GO_REF:0000033 | ACCEPT | Summary: Nuclear localization of the Ets1 transcription factor. Reason: A sequence-specific transcription factor acting on chromatin; frog Ets1a occupies the id3 promoter in embryo ChIP, and ortholog Ets1 binds the Sox10E2 enhancer in vivo. Nucleus is the functional location. Supporting Evidence: file:XENLA/ets1-a/ets1-a-deep-research-falcon.md FLAG-tagged frog Ets1a occupied its predicted binding region in embryo chromatin-immunoprecipitation assays. PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. |
| GO:0005634 nucleus | IEA GO_REF:0000120 | ACCEPT | Summary: Nuclear localization of the Ets1 transcription factor. Reason: A sequence-specific transcription factor acting on chromatin; frog Ets1a occupies the id3 promoter in embryo ChIP, and ortholog Ets1 binds the Sox10E2 enhancer in vivo. Nucleus is the functional location. Supporting Evidence: file:XENLA/ets1-a/ets1-a-deep-research-falcon.md FLAG-tagged frog Ets1a occupied its predicted binding region in embryo chromatin-immunoprecipitation assays. PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. |
| GO:0005634 nucleus | ISS GO_REF:0000024 | ACCEPT | Summary: Nuclear localization of the Ets1 transcription factor. Reason: A sequence-specific transcription factor acting on chromatin; frog Ets1a occupies the id3 promoter in embryo ChIP, and ortholog Ets1 binds the Sox10E2 enhancer in vivo. Nucleus is the functional location. Supporting Evidence: file:XENLA/ets1-a/ets1-a-deep-research-falcon.md FLAG-tagged frog Ets1a occupied its predicted binding region in embryo chromatin-immunoprecipitation assays. PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. |
| GO:0005634 nucleus | ISS GO_REF:0000024 | ACCEPT | Summary: Nuclear localization of the Ets1 transcription factor. Reason: A sequence-specific transcription factor acting on chromatin; frog Ets1a occupies the id3 promoter in embryo ChIP, and ortholog Ets1 binds the Sox10E2 enhancer in vivo. Nucleus is the functional location. Supporting Evidence: file:XENLA/ets1-a/ets1-a-deep-research-falcon.md FLAG-tagged frog Ets1a occupied its predicted binding region in embryo chromatin-immunoprecipitation assays. PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. |
| GO:0005737 cytoplasm | IEA GO_REF:0000044 | KEEP AS NON CORE | Summary: Cytoplasmic localization transferred from human ETS1 (UniProt subcellular location). Reason: Human ETS1 has been detected in the cytoplasm and ETS1 activity is regulated in part by nucleocytoplasmic distribution, so the transfer is plausible, but there is no frog localization data and the cytoplasm is not where Ets1 carries out its function; its activity is at nuclear cis-regulatory elements. Supporting Evidence: file:XENLA/ets1-a/ets1-a-deep-research-falcon.md FLAG-tagged frog Ets1a occupied its predicted binding region in embryo chromatin-immunoprecipitation assays. |
| GO:0005737 cytoplasm | ISS GO_REF:0000024 | KEEP AS NON CORE | Summary: Cytoplasmic localization transferred from human ETS1 (UniProt subcellular location). Reason: Human ETS1 has been detected in the cytoplasm and ETS1 activity is regulated in part by nucleocytoplasmic distribution, so the transfer is plausible, but there is no frog localization data and the cytoplasm is not where Ets1 carries out its function; its activity is at nuclear cis-regulatory elements. Supporting Evidence: file:XENLA/ets1-a/ets1-a-deep-research-falcon.md FLAG-tagged frog Ets1a occupied its predicted binding region in embryo chromatin-immunoprecipitation assays. |
| GO:0006355 regulation of DNA-templated transcription | IEA GO_REF:0000002 | ACCEPT | Summary: Regulation of DNA-templated transcription from the InterPro ETS domain mapping. Reason: Correct, general electronic process annotation for a sequence-specific transcription factor. Supporting Evidence: PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. PMID:26198637 Mechanistically, we found that Ets1 binds to id3 promoter as well as histone deacetylase 1, suggesting that Ets1 recruits histone deacetylase 1 to the promoter of id3, thereby inducing histone deacetylation of the id3 promoter. |
| GO:0006357 regulation of transcription by RNA polymerase II | IBA GO_REF:0000033 | ACCEPT | Summary: Regulation of transcription by RNA polymerase II, inherited from the ETS family. Reason: Ets1 regulates RNA polymerase II target genes both positively (cranial Sox10E2 enhancer, msmb3) and negatively (id3, via HDAC1 recruitment). Appropriate general process. Supporting Evidence: PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. PMID:26198637 Mechanistically, we found that Ets1 binds to id3 promoter as well as histone deacetylase 1, suggesting that Ets1 recruits histone deacetylase 1 to the promoter of id3, thereby inducing histone deacetylation of the id3 promoter. |
| GO:0006357 regulation of transcription by RNA polymerase II | IEA GO_REF:0000120 | ACCEPT | Summary: Regulation of transcription by RNA polymerase II, inherited from the ETS family. Reason: Ets1 regulates RNA polymerase II target genes both positively (cranial Sox10E2 enhancer, msmb3) and negatively (id3, via HDAC1 recruitment). Appropriate general process. Supporting Evidence: PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. PMID:26198637 Mechanistically, we found that Ets1 binds to id3 promoter as well as histone deacetylase 1, suggesting that Ets1 recruits histone deacetylase 1 to the promoter of id3, thereby inducing histone deacetylation of the id3 promoter. |
| GO:0010595 positive regulation of endothelial cell migration | ISS GO_REF:0000024 | KEEP AS NON CORE | Summary: Positive regulation of endothelial cell migration, transferred from human ETS1 (IMP, PMID:15592518). Reason: Ets1 is a conserved endothelial transcription factor and frog ets-1 is expressed in hemangioblastic precursors and endothelial cells of the forming heart and vessels, so the transfer is biologically plausible. No Xenopus functional data test endothelial migration, and in frog the best-characterized roles are in neural crest and heart mesoderm; keep as non-core. Supporting Evidence: PMID:9303349 Specific transcription can also be observed for ets-1 in the hemangioblastic precursors, in endothelial cells of the forming heart and blood vessels. |
| GO:0030154 cell differentiation | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: Cell differentiation, a very general process inherited across the ETS family. Reason: Not wrong, since ETS factors act in many lineage programmes, but uninformative. The specific roles supported for Xenopus Ets1 (neural crest delamination and migration, endocardium development) are proposed as NEW terms. Supporting Evidence: file:XENLA/ets1-a/ets1-a-deep-research-falcon.md Thus, impaired migration and delamination are better-established physiological outcomes than an absolute requirement for initial whole-embryo crest induction. PMID:25691536 The formation of the primitive heart tube was dramatically delayed and the endocardial tissue appeared depleted. |
| GO:0030154 cell differentiation | IEA GO_REF:0000118 | KEEP AS NON CORE | Summary: Cell differentiation, a very general process inherited across the ETS family. Reason: Not wrong, since ETS factors act in many lineage programmes, but uninformative. The specific roles supported for Xenopus Ets1 (neural crest delamination and migration, endocardium development) are proposed as NEW terms. Supporting Evidence: file:XENLA/ets1-a/ets1-a-deep-research-falcon.md Thus, impaired migration and delamination are better-established physiological outcomes than an absolute requirement for initial whole-embryo crest induction. PMID:25691536 The formation of the primitive heart tube was dramatically delayed and the endocardial tissue appeared depleted. |
| GO:0043565 sequence-specific DNA binding | IEA GO_REF:0000002 | ACCEPT | Summary: Sequence-specific DNA binding from ETS and PNT domain InterPro signatures. Reason: Correct; the ETS domain recognizes GGA(A/T)-core motifs. The more precise cis-regulatory term is proposed via the DNA binding MODIFY. Supporting Evidence: PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. |
| GO:0045648 positive regulation of erythrocyte differentiation | ISS GO_REF:0000024 | MARK AS OVER ANNOTATED | Summary: Positive regulation of erythrocyte differentiation, transferred from a single human ETS1 IDA (PMID:8620536). Reason: The source is a human cell-based result; there is no Xenopus evidence that Ets1a regulates erythroid differentiation. Frog ets-1 is expressed in hemangioblastic precursors, but its documented functional roles are endothelial/endocardial and neural crest. Transferring a peripheral erythroid regulatory claim by sequence similarity overstates what is known for this protein. Supporting Evidence: PMID:9303349 Specific transcription can also be observed for ets-1 in the hemangioblastic precursors, in endothelial cells of the forming heart and blood vessels. |
| GO:0045765 regulation of angiogenesis | ISS GO_REF:0000024 | KEEP AS NON CORE | Summary: Regulation of angiogenesis, transferred from human ETS1 (IMP, PMID:15592518). Reason: Conserved vascular role of Ets1 and frog endothelial expression make this plausible; not tested in Xenopus and peripheral to the embryonic neural crest and endocardial roles. Supporting Evidence: PMID:9303349 Specific transcription can also be observed for ets-1 in the hemangioblastic precursors, in endothelial cells of the forming heart and blood vessels. |
| GO:0045893 positive regulation of DNA-templated transcription | ISS GO_REF:0000024 | ACCEPT | Summary: Positive regulation of DNA-templated transcription, transferred from human ETS1. Reason: Ets1 is primarily a transcriptional activator; the chick ortholog directly activates the cranial Sox10E2 enhancer, and Ets1 positively regulates msmb3 in Xenopus. Ets1a can also repress (id3, via HDAC1), so both directions occur, but activation is the principal mode. Supporting Evidence: PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. PMID:20139305 Three transcription factors, Sox9, Ets1, and cMyb, acting via one of the identified enhancers, Sox10E2, are required for direct initial activation of endogenous Sox10 expression and the specification of delaminating/migrating cranial NC. |
| GO:0001228 DNA-binding transcription activator activity, RNA polymerase II-specific | ISS PMID:20139305 Genomic code for Sox10 activation reveals a key regulatory e... | NEW | Summary: Ets1 directly binds ETS motifs in the cranial Sox10E2 enhancer and is required for its activation and for onset of endogenous Sox10 in cranial neural crest (chick ortholog). Reason: The existing MF annotations stop at generic DNA-binding transcription factor activity. Activation is the principal mode of Ets1 action, shown in vivo for the ortholog by ChIP, gel shift and binding-site mutation, and human ETS1 carries this term by IDA. Repression of id3 via HDAC1 in frog overexpression assays is context-dependent and not proposed as a separate MF. Supporting Evidence: PMID:20139305 ChIP, DNA-pull down, and gel-shift assays demonstrate their direct binding to the Sox10E2 enhancer in vivo, whereas mutation of their corresponding binding sites, or inactivation of the three upstream regulators, abolishes both reporter and endogenous Sox10 expression. PMID:20139305 Three transcription factors, Sox9, Ets1, and cMyb, acting via one of the identified enhancers, Sox10E2, are required for direct initial activation of endogenous Sox10 expression and the specification of delaminating/migrating cranial NC. |
| GO:0001755 neural crest cell migration | IMP PMID:25691536 Dual developmental role of transcriptional regulator Ets1 in... | NEW | Summary: Ets1 knockdown in Xenopus neural crest disrupts collective migration and segregation of cranial and cardiac crest streams; transplantation shows the requirement is within the crest. Reason: Synthesis of expression in premigratory and migratory crest, crest-autonomous loss of function in frog (morpholino and transplantation), chick gain/loss of function, and downstream migratory targets (msmb3). Ets1 acts as a transcription factor within the migrating cells, the same role in which other Xenopus TFs (sox10.S, snai2.S, hic1.L, kmt2d.L) carry this term. Note that frog reagents targeted both homeologs. Supporting Evidence: PMID:25691536 Using a translation-blocking antisense morpholino to knockdown Ets1 protein selectively in the NC, we observed defects in NC delamination from the neural tube, collective cell migration, as well as segregation of NC streams in the cranial and cardiac regions. file:XENLA/ets1-a/ets1-a-deep-research-falcon.md Independently, transplantation of Ets1-depleted cranial-crest tissue into wild-type hosts supported a requirement within the crest for normal migration. PMID:32713114 The proto-oncogene ets1 is highly expressed in the pre-migratory and migratory neural crest (NC), and has been implicated in the delamination and migration of the NC cells. file:XENLA/ets1-a/ets1-a-deep-research-falcon.md These experiments show distinct tissue requirements but used a morpholino recognizing both Ets1a and Ets1b. |
| GO:0036032 neural crest cell delamination | IMP PMID:25691536 Dual developmental role of transcriptional regulator Ets1 in... | NEW | Summary: Ets1 is required for neural crest delamination from the neural tube in Xenopus, and in chick it is required and sufficient for the cranial-type mass recruitment and basal lamina breaching that make up cranial delamination. Reason: Frog crest-targeted knockdown shows delamination defects, and chick gain and loss of function show that ets-1 drives cranial delamination (sufficient for ectopic delamination; dominant-negative blocks cranial but not trunk delamination). This is the most specific process for which Ets1 is both necessary and sufficient. Chick SOX9 carries the same term. Supporting Evidence: PMID:25691536 Using a translation-blocking antisense morpholino to knockdown Ets1 protein selectively in the NC, we observed defects in NC delamination from the neural tube, collective cell migration, as well as segregation of NC streams in the cranial and cardiac regions. PMID:17987123 We show that ets-1 promotes massive cell recruitment and induces local degradations of the basal lamina, two separable events which are sufficient to initiate ectopic delaminations. PMID:17987123 Altogether, these data show a specific requirement of ets-1 in cranial NCCs delamination. |
| GO:0003157 endocardium development | IMP PMID:25691536 Dual developmental role of transcriptional regulator Ets1 in... | NEW | Summary: Ets1 knockdown targeted to Xenopus heart mesoderm delays heart tube formation and depletes endocardial tissue, with loss of trabeculae. Reason: Tissue-targeted loss of function separates a heart-mesoderm role from the cardiac neural crest role; ets-1 is expressed in endothelial cells of the forming heart, consistent with a cell-autonomous transcriptional role in endocardial precursors. Kept at the development level because no direct endocardial target has been identified, and the morpholino targeted both homeologs. Supporting Evidence: PMID:25691536 The formation of the primitive heart tube was dramatically delayed and the endocardial tissue appeared depleted. PMID:9303349 Specific transcription can also be observed for ets-1 in the hemangioblastic precursors, in endothelial cells of the forming heart and blood vessels. file:XENLA/ets1-a/ets1-a-deep-research-falcon.md These experiments show distinct tissue requirements but used a morpholino recognizing both Ets1a and Ets1b. |
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Download this section (compressed HTML)Q: Should Ets1 be annotated to neural crest cell fate specification? In chick it directly activates the Sox10E2 enhancer needed for initial Sox10 expression in cranial crest, but in Xenopus combined ets1a/ets1b knockdown leaves early foxd3/snai2 expression largely intact. Is this a species difference, homeolog redundancy, or a sign that Ets1 acts after specification?
Q: GO has no neural plate border specification/formation process term. Ets1 is not a border gene (its onset follows Brn3c/Lhx5/Dmbx1 and depends on Tfap2b), but should a border term be created so that border specifiers and late crest specifiers such as Ets1 can be distinguished in annotation?
Q: Do ets1a (ets1.S, P18755) and ets1b (ets1.L) have divergent roles in Xenopus neural crest versus heart mesoderm, given that ets1b is reported to be more prominent in presumptive crest and all loss-of-function reagents target both?
Q: Is the HDAC1-dependent repression of id3 seen on overexpression a physiological activity of endogenous Ets1 in crest cells, or a dosage artefact?
Experiment: Generate homeolog-specific CRISPR F0 mutants (ets1.S vs ets1.L) in X. laevis, assay delamination, stream segregation (sox10, twist1) and endocardial markers, and rescue with each homeolog mRNA.
Hypothesis: ets1a and ets1b make separable contributions to neural crest delamination/migration and to endocardium formation.
Experiment: CUT&RUN with an epitope-tagged knock-in ets1 allele on dissected premigratory cranial crest, combined with ATAC-seq after ets1 knockdown and enhancer-reporter mutagenesis of bound ETS sites.
Hypothesis: Endogenous Ets1 directly occupies and activates cranial crest enhancers (Sox10E2 orthologous region, msmb3, alx1) in Xenopus.
Experiment: Electroporate gnathostome or lamprey Ets1 under a lamprey crest enhancer into lamprey embryos and score delamination timing, cell recruitment and Sox10 enhancer activity.
Hypothesis: Deploying Ets1 in lamprey premigratory crest is sufficient to confer gnathostome-like cranial delamination behaviour.
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