Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10934033 | Developmental Biology | 2005 | 12 Pages |
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 5â²Hoxd. We reported previously that polydactyly in Alx4 mutant mice requires SHH signaling, but we now show that in early Alx4â/â 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 Shhâ/â background. Total lack of reporter expression in a Gli3â/â 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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Authors
Sanne Kuijper, Harma Feitsma, Rushikesh Sheth, Jeroen Korving, Mark Reijnen, Frits Meijlink,