Reelin is transiently expressed in the peripheral nerve during early development and is upregulated following nerve injury.

Reelin is an extracellular matrix protein which is critical for the positioning of migrating post-mitotic neurons and the laminar organisation of several brain structures during development. We investigated the expression and localization of Reelin in the rodent sciatic nerve during postnatal development and following crush injury in the adult stage. As shown with Western blotting, immunocytochemistry and RT-PCR, Schwann cells in the developing sciatic nerve and in primary cultures from neonatal nerves produce and secrete Reelin. In the sciatic nerve Reelin co-localizes with the compact myelin marker MBP and with the Schwann cell marker S100. While Reelin levels are down-regulated in adult stages, they are again induced following sciatic nerve crush. A morphometric analysis of sciatic nerve sections of reeler mice suggests that Reelin is not essential for axonal ensheathment by Schwann cells, however, influences the caliber of myelinated axons and the absolute number of fibers per unit area. This indicates that Reelin may play a role in peripheral nervous system development and repair by regulating Schwann cell-axon interactions.