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

Several molecules have been identified as potential sources of the barriers to glial cell mixing and sensory regeneration that exist at the boundary b etween the peripheral and central nervous systems, including tenasch-C, ten ascin-R, chondroitin sulfate proteoglycans, and NG2. Here we show that tena scin-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 dos e-dependent effects on glial cell attachment, spreading, and migration. In addition, nanomolar concentrations of tenascin-Y cause the rapid collapse o f sensory growth cones cultured on fibronectin, and regenerating sensory ne urites preferentially migrate on fibronectin and avoid tenascin-Y in micros tripe 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 ce ll migration and sensory regeneration in nerve roots. (C) 2001 Wiley-Liss, Inc.