Tenascin-Y is concentrated in adult nerve roots and has barrier properties in vitro.

Several molecules have been identified as potential sources of the barriers to glial cell mixing and sensory regeneration that exist at the boundary between the peripheral and central nervous systems, including tenascin-C, tenascin-R, chondroitin sulfate proteoglycans, and NG2. Here we show that tenascin-Y, the avian homologue of tenascin-X, is concentrated in the proximal portions of peripheral nerves in the chicken. In vitro analyses of cultures enriched for Schwann cells demonstrate that recombinant tenascin-Y has dose-dependent effects on glial cell attachment, spreading, and migration. In addition, nanomolar concentrations of tenascin-Y cause the rapid collapse of sensory growth cones cultured on fibronectin, and regenerating sensory neurites preferentially migrate on fibronectin and avoid tenascin-Y in microstripe assays. We conclude that the expression pattern of tenascin-Y and its properties in vitro are consistent with a role as an inhibitor of glial cell migration and sensory regeneration in nerve roots.