Impaired Axonal Regeneration in a7 Integrin-Deficient Mice

The interplay between growing axons and the extracellular substrate is pivotal for directing axonal outgrowth during development and regeneration. Here we show an important role for the neuronal cell adhesion molecule a7b1 integrin during peripheral nerve regeneration. Axotomy led to a strong increase of this integrin on regenerating motor and sensory neurons, but not on the normally nonregenerating CNS neurons. a7 and b1 subunits were present on the axons and their growth cones in the regenerating facial nerve. Transgenic deletion of the a7 subunit caused a significant reduction of axonal elongation. The associated delay in the reinnervation of the whiskerpad, a peripheral target of the facial motor neurons, points to an important role for this integrin in the successful execution of axonal regeneration.