The Xvex-1 antimorph reveals the temporal competence for organizer formation and an early role for ventral homeobox genes.
Mech Dev
; 90(1): 77-87, 2000 Jan.
Article
em En
| MEDLINE
| ID: mdl-10585564
ABSTRACT
The organizer in vertebrate embryos has been shown to play a central role in their development by antagonizing ventralizing signals and promoting dorsal development. The ventral homeobox gene, Xvex-1, is capable of fulfilling some of the functions of BMP-4. By fusion to activation and repression domains, Xvex-1 was shown to function as a repressor of transcription. The activator version of Xvex-1, the antimorph, was made inducible by fusion to the ligand binding domain of the glucocorticoid receptor. The organizer genes, gsc and Otx-2, were identified as direct targets of Xvex-1. The XVEX-1 antimorph can induce the formation of secondary axes. Temporal analysis of secondary axis induction revealed that the competence to induce a secondary organizer ends with the onset of gastrulation. The same temporal competence window was exhibited by an inducible gsc construct. Partial loss of Xvex-1 activity was able to improve the efficiency of secondary axis induction by the dominant negative BMP receptor or Smad6. These observations together with the early widespread expression of Xvex-1 throughout the embryo prior to gastrulation encoding a homeodomain repressor protein, suggest that elements of the ventral signaling pathway play an important role during late blastula in restricting the formation of Spemann's organizer.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Xenopus
/
Proteínas de Homeodomínio
/
Regulação da Expressão Gênica no Desenvolvimento
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Proteínas Morfogenéticas Ósseas
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Proteínas de Xenopus
Limite:
Animals
Idioma:
En
Ano de publicação:
2000
Tipo de documento:
Article