Tenascin-C glycoproteins in neural pattern formation and plasticity

It is widely accepted that astroglia plays an important role in the regulation of neural pattern formation, for example by guiding migrating neuroblasts and growth cones or by designing transient tissue boundaries. In this context, the tenascin-C glycoproteins of the extracellular matrix have attracted increased attention, because they are selectively expressed by glial lineages in the brain and exert both stimulatory and inhibitory effects on CNS neurons. Several lines of evidence suggest that these properties are encoded by distinct molecular domains. This concept has been probed by the use of recombinant proteins in various in-vitro assays. The present review summarizes these studies which show that several functions of tenascin-C can be reproduced with isolated, defined segments of the molecule.