Mechanistic insight into how Shh patterns the vertebrate limb.
- ISSN: 0959437X
- ISBN: 0959-437X (Print)\r0959-437X (Linking)
- DOI: 10.1016/j.gde.2006.10.010
- PubMed: 16806898
The hands and feet of a newborn baby are a beautiful reminder of the complexity of embryonic patterning. Classical studies on how these structures form have led to a theoretical framework for understanding, in general, how discrete groups of cells can instruct differential fates across a wider field through the action of long-range signals. The discovery just more than a decade ago that localized expression of Sonic hedgehog (Shh) differentially patterns structures across the limb field, resulting in digits with unique characteristics, provided a starting point for readdressing these models at a molecular level. Current research has revealed unexpected complexity in how a gradient of Shh activity is both established and received, prompting re-evaluation of the nature of patterning mechanisms within the limb.