Extended exposure to Sonic hedgehog is required for patterning the posterior digits of the vertebrate limb.

ABSTRACT: Sonic hedgehog (Shh) is a key signal in establishing different digit fates along the anterior-posterior axis of the vertebrate limb bud. Although the anterior digits appear to be specified by differential concentrations of Shh in a traditional, morphogen-like response, recent studies have suggested that posterior digits are specified by an extended time of exposure to Shh rather than, or in addition to, a threshold concentration of Shh. This model for digit patterning depends upon continued Shh signaling in the posterior limb through mid-to-late bud stages. We find that cyclopamine, a potent antagonist of Shh signaling, can down-regulate hedgehog target genes in the posterior limb throughout the time Shh is expressed, indicating that continued active Shh signaling indeed takes place. To fu

SUBMITTER: Scherz PJ 

PROVIDER: S-EPMC2100419 | biostudies-literature | 2007 Aug

REPOSITORIES: biostudies-literature