p200, a collagen secreted by Schwann cells, is expressed in developing nerves and in adult nerves following axotomy

Previously we reported that cultured rat Schwann cells secrete p200, a coll agen-like heparin-binding adhesive glycoprotein with a restricted pattern o f expression. Here we report that p200 is secreted as a stable trimer, but only after treatment of Schwann cells with ascorbic acid, and was deposited in the fibrillar extracellular matrix. Heparin and heparitinase treatment inhibited incorporation of p200 into extracellular matrix, suggesting the i nvolvement of Schwann cell heparan sulfate proteoglycans in this process. P epsin digestion revealed that p200 secreted by ascorbate-treated cells cont ains a collagenous domain of approximately 140 kDa. Immunofluorescent stain ing of rat embryos at different ages slowed that p200 first appeared betwee n embryonic days 15 and 18, and was confined to peripheral nerves. Staining of adult peripheral nerve was negative, but p200 expression was induced in adult sciatic nerve following nerve transection. These data suggest that p 200 carries out unique functions during peripheral nerve development and re generation and that its expression by Schwann cells is regulated by axon-Sc hwann cell interaction. J. Neurosci. Res. 56:284-294, 1999. (C) 1999 Wiley- Liss, Inc.