Gene Ontology annotation through association of InterPro records with GO terms
Annotation inferences using phylogenetic trees
TreeGrafter-generated GO annotations
Combined Automated Annotation using Multiple IEA Methods
Expression of gbx2 in the neural plate border
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Reactome models direct Wnt/TCF activation of the gbx2 promoter in the neural plate border (regulation of gbx2, not an activity of Gbx2).
"Canonical Wnt signaling activates expression of gbx2 in the neural plate border via direct binding of tcf7l1:ctnnb1 (tcf3:beta-catenin) to the promoter of the gbx2 gene (Li et al. 2009)."
Deep research report for Xenopus laevis gbx2 (falcon)
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Full-text-based summary of Li 2009 epistasis, placing Gbx2 upstream of Pax3/Msx1.
"At gastrula stages, depletion reduced *pax3* and *msx1*; supplying Pax3 or Msx1 restored downstream crest markers, whereas supplying Gbx2 did not rescue Pax3/Msx1 inhibition."
The posteriorizing gene Gbx2 is a direct target of Wnt signalling and the earliest factor in neural crest induction.
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Gbx2 is a direct Wnt/beta-catenin target and is required for neural crest induction, upstream of Pax3 and Msx1 and dependent on Zic1.
"Our results place Gbx2 as the earliest factor in the NC genetic cascade being directly regulated by the inductive molecules, and support the notion that posteriorization of the neural folds is an essential step in NC specification."
Mutual repression between Gbx2 and Otx2 in sensory placodes reveals a general mechanism for ectodermal patterning.
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Gbx2 and Otx2 mutually repress each other as transcriptional repressors in the pre-placodal region, and Gbx2 is required for otic specification.
"Thus, Gbx2 is required for otic, but not for PPR specification."
Directional cell movements downstream of Gbx2 and Otx2 control the assembly of sensory placodes.
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Repressing Gbx2 targets with an inducible Gbx2-EnR reduces the persistence of placodal cell movement.
"Automatic cell tracking reveals that when Gbx2 targets are repressed, the persistence of movement is decreased"
Gbx2 interacts with Otx2 and patterns the anterior-posterior axis during gastrulation in Xenopus.
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Xgbx2a acts as a transcriptional repressor and represses Otx2 at gastrula stages to set up the Otx2/Gbx2 boundary.
"Using obligatory activator and repressor versions of Xgbx2a, we demonstrate that, during early embryogenesis, Xgbx2a acts as a transcriptional repressor."
Otx2 can activate the isthmic organizer genetic network in the Xenopus embryo.
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In frog, Otx2 induces the MHB network, while Gbx2 restricts Otx2 and the MHB genes.
"In contrast, Gbx2 is a negative regulator of Otx2 and the MHB genes."
The two Xenopus Gbx2 genes exhibit similar, but not identical expression patterns and can affect head formation.
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X. laevis has two Gbx2 genes encoding functionally homologous proteins.
"Both genes encode functionally homologous proteins, which differ primarily in their temporal and spatial expression patterns."
The Xenopus laevis homeobox gene Xgbx-2 is an early marker of anteroposterior patterning in the ectoderm.
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Original cloning of Q91907. Expressed from mid-gastrula in dorsolateral ectoderm, with its anterior neural border at the MHB.
"Expression of Xgbx-2 is first detectable by in situ hybridization at the midgastrula stage when it is predominantly expressed in the dorsolateral ectoderm, with a gap in expression at the dorsal midline."
Anterior structural defects by misexpression of Xgbx-2 in early Xenopus embryos are associated with altered expression of cell adhesion molecules.
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Xgbx-2 misexpression disrupts anterior structures and reduces N-cadherin expression and Ca2+-dependent adhesion (gain of function only).
"misexpression of Xgbx-2 prevents N-cadherin expression during early neurulation"
Gbx2 and Otx2 interact with the WD40 domain of Groucho/Tle corepressors.
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An eh1-like motif in Gbx2 binds Groucho/TLE, which is required for Gbx2 repression of Otx2 (cell culture and medaka).
"In addition, heat shock-induced expression of wild-type and mutant Otx2 and Gbx2 in medaka embryos demonstrates that Groucho is required for the repression of Otx2 by Gbx2."
Zebrafish gbx1 refines the midbrain-hindbrain boundary border and mediates the Wnt8 posteriorization signal.
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In zebrafish, the Gbx paralog gbx1 mediates Wnt8 posteriorization, which shows that the Wnt-to-Gbx link is conserved.
"Considering that Wnt8 is required for the onset of gbx1 expression, as well as for the correct A-P positioning of its expression domain [32], we propose that gbx1 acts at the transcriptional level to mediate Wnt8 posteriorizing effects on hindbrain patterning."
Apolipoprotein C-I mediates Wnt/Ctnnb1 signaling during neural border formation and is required for neural crest development.
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Refers to the Wnt-target Gbx2 as gbx2.2, matching Q91907's Xenbase gene.
"However, unlike another Wnt/Ctnnb1 target, gbx2.2, apoc1 is not required for patterning of the neural border."
Patterning of the Vertebrate Head in Time and Space by BMP Signaling.
Pax3 and Zic1 trigger the early neural crest gene regulatory network by the direct activation of multiple key neural crest specifiers.
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Gbx2 is listed among the neural border specifiers.
"These neural border specifiers include the transcription factors Pax3, Pax7, Gbx2, Msx1, Zic1, AP2, and Hairy2"
Identification of Pax3 and Zic1 targets in the developing neural crest.
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gbx2 is induced by Pax3+Zic1 in animal caps, which suggests feedback within the border module.
"This group included 10 well-characterized NC-specific genes: ednra, foxd3, gbx2, olig4, snail2, sox8, sox9, tcf7, twist and zic5 (Table 2)."
Pax3 and Zic1 drive induction and differentiation of multipotent, migratory, and functional neural crest in Xenopus embryos.
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Gbx2 is described as essential for neural border specification.
"In addition, Pax3/Pax7, Gbx2, and Zic1 are also essential for neural border specification"
Shared features of blastula and neural crest stem cells evolved at the base of vertebrates.
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Lamprey gbx2 shows neural plate border expression dynamics like Xenopus gbx2.
"In both lamprey and Xenopus, clusters with this signature included canonical neural plate border factors such as prdm1, gbx2 and wnt8"
A Gbx homeobox gene in amphioxus: insights into ancestry of the ANTP class and evolution of the midbrain/hindbrain boundary.
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Amphioxus has a single Gbx whose CNS domain abuts Otx, so the MHB-positioning machinery is chordate-ancestral, while organizer induction is not.
"Amphioxus Gbx is expressed in all germ layers in the posterior 75% of the embryo, and in the CNS, the Gbx and Otx domains abut at the boundary between the cerebral vesicle (forebrain/midbrain) and the hindbrain."
Gene duplication, co-option and recruitment during the origin of the vertebrate brain from the invertebrate chordate brain.
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Amphioxus expresses border and Gbx/Otx genes in vertebrate-like patterns but lacks neural crest specifier expression at the neural plate edge.
"However, migratory neural crest is lacking in amphioxus, and although it has homologs of the genes that specify neural crest, they are not expressed at the edges of the amphioxus neural plate."
A genomewide survey of developmentally relevant genes in Ciona intestinalis. II. Genes for homeobox transcription factors.