Function and regulation of Alx4 in limb development: complex genetic interactions with Gli3 and Shh.
Dev Biol
; 285(2): 533-44, 2005 Sep 15.
Article
em En
| MEDLINE
| ID: mdl-16039644
ABSTRACT
The role of the aristaless-related homeobox gene Alx4 in antero-posterior (AP-) patterning of the developing vertebrate limb has remained somewhat elusive. Polydactyly of Alx4 mutant mice is known to be accompanied by ectopic anterior expression of genes like Shh, Fgf4 and 5'Hoxd. We reported previously that polydactyly in Alx4 mutant mice requires SHH signaling, but we now show that in early Alx4-/- limb buds the anterior ectopic expression of Fgf4 and Hoxd13, and therefore disruption of AP-patterning, occurs independently of SHH signaling. To better understand how Alx4 functions in the pathways that regulate AP-patterning, we also studied genomic regulatory sequences that are capable of directing expression of a reporter gene in a pattern corresponding to endogenous Alx4 expression in anterior limb bud mesenchyme. We observed, as expected for authentic Alx4 expression, expansion of reporter construct expression in a Shh-/- background. Total lack of reporter expression in a Gli3-/- background confirms the existence of Gli3-dependent and -independent Alx4 expression in the limb bud. Apparently, these two modules of Alx4 expression are linked to dissimilar functions.
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Base de dados:
MEDLINE
Assunto principal:
Transdução de Sinais
/
Transativadores
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Proteínas de Homeodomínio
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Padronização Corporal
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Fatores de Transcrição Kruppel-Like
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Extremidades
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Proteínas do Tecido Nervoso
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article