Wnt signalling during limb development.

Wnts control a number of processes during limb development--from initiating outgrowth and controlling patterning, to regulating cell differentiation in a number of tissues. Interactions of Wnt signalling pathway components with those of other signalling pathways have revealed new mechanisms of modulating Wnt signalling, which may explain how different responses to Wnt signalling are elicited in different cells. Given the number of Wnts that are expressed in the limb and their ability to induce differential responses, the challenge will be to dissect precisely how Wnt signalling is regulated and how it controls limb development at a cellular level, together with the other signalling pathways, to produce the functional limb capable of coordinated precise movements.