Gene Ontology annotation through association of InterPro records with GO terms
Annotation inferences using phylogenetic trees
Electronic Gene Ontology annotations created by transferring manual GO annotations between related proteins based on shared sequence features
Combined Automated Annotation using Multiple IEA Methods
Brn1/2/4, the predicted midgut regulator of the endo16 gene of the sea urchin embryo.
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Sp-Brn1/2/4 is a POU domain factor closely related to mammalian Brain-1, -2 and -4, cloned as the predicted midgut regulator of endo16.
"The cDNA sequence reveals it to be a POU domain factor related closely to the mammalian factors Brain-1, -2, and -4."
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Zygotic activation at 20 h at about 100 molecules per embryo, then an abrupt ten-fold increase at the start of gastrulation; expression confined to the gut (midgut) coincident with endo16.
"the gene is first activated in the 20-h blastula, but there remain only about 100 molecules of brn1/2/4 mRNA per embryo (only a few per endoderm cell) until an abrupt 10-fold increase occurs as gastrulation begins."
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Morpholino knockdown blocks the late phase of endo16 expression and specifically abolishes Module B-driven expression, not Module A.
"Arrest of Brn1/2/4 translation by MASO treatment blocks the late phase of endo16 expression and specifically abolishes expression of cis-regulatory Module B of endo16, while not affecting Module A, also as predicted."
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brn1/2/4 lies downstream of the regulatory genes executing post-gastrular midgut specification.
"The brn1/2/4 gene lies downstream of the regulatory genes executing post-gastrular specification of the midgut, as shown by further gene expression perturbation experiments which provide an initial glimpse of the underlying network architecture."
A gene regulatory network controlling the embryonic specification of endoderm.
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brn1/2/4 is activated in veg2-derived (anterior endoderm) cells in the final hours before gastrulation, by 27 h.
"A few additional regulatory genes are activated in the final hours before gastrulation: brn1/2/4, gatae, dac and tgif are expressed in veg2-derived cells and hnf1 is expressed in the veg1 endoderm domain by 27 h after fertilization."
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Blimp1 activates brn1/2/4 in veg2 endoderm; the veg1 regulator Eve affects it only indirectly through a proposed signal.
"Blimp1 then activates brn1/2/4 and tgif expression (Fig. 1f)."
Regulation of spblimp1/krox1a, an alternatively transcribed isoform expressed in midgut and hindgut of the sea urchin gastrula.
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The midgut/hindgut cis-regulatory module of blimp1/krox1a contains predicted Brn1/2/4 binding sites.
"Its sequence contains binding sites for Brn1/2/4, Otx, and Blimp1/Krox itself, as predicted in a prior regulatory network analysis."
Fluorescent in situ hybridization reveals multiple expression domains for SpBrn1/2/4 and identifies a unique ectodermal cell type that co-expresses the ParaHox gene SpLox.
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By FISH, endodermal SpBrn1/2/4 expression is restricted to the foregut, with additional domains in stomodeal ectoderm and scattered ciliary band cells, some co-expressing SpLox.
"Endodermal expression of this gene is restricted to the foregut. SpBrn1/2/4 is also expressed in two distinct ectodermal domains: throughout the stomodeal ectoderm, and within cells scattered throughout the ciliated band."
Neurogenic gene regulatory pathways in the sea urchin embryo.
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Brn1/2/4 acts downstream of SoxC in the neurogenic regulatory pathway and is required for differentiation of all neurons.
"Using a combination of molecular screens and tests of gene function by morpholino-mediated knockdown, we identified SoxC and Brn1/2/4 , which function sequentially in the neurogenic regulatory pathway and are also required for the differentiation of all neurons."
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Brn1/2/4 knockdown prevents serotonergic and SynB-expressing neuron development; low-dose misexpression gives excess neurons.
"We conclude that Brn1/2/4 is required for the development of serotonergic and all SynB -expressing neurons and can directly or indirectly drive the production of excess neurons at low dose"
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Ectodermal (neural precursor) Brn1/2/4 expression depends on SoxC; foregut expression does not.
"in SoxC morphants, labeling of individual ectoderm cells for Brn1/2/4 transcripts was dramatically reduced, whereas expression in the foregut was not detectably affected"
New Neuronal Subtypes With a "Pre-Pancreatic" Signature in the Sea Urchin Stongylocentrotus purpuratus.
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Human Brn1, Brn2, Brn4 and Oct6 are equal co-orthologs of SpBrn1/2/4 (POU3 family).
"The human genes Brn1, Brn2, Brn4, and Oct6 are all equal co-orthologs of the sea urchin gene SpBRN1/2/4"