Interaction of sulfoglucuronyl (HNK-1) carbohydrate and its binding protein, SBP-1, in microexplant cultures of rat cerebellum

Sulfoglucurony[ carbohydrate (SGC) is expressed on several neural cell-adhe sion molecules and on glycolipids. SGC and its binding protein, SEP-I. are developmentally regulated in the nervous system and have been implicated in regulating neurite outgrowth and cell-cell recognition during neuronal cel l migration. To elucidate the role of interaction between SGC and SBP-1, mi cro-explant cultures of postnatal day 5 rat cerebellum were employed. In ex p[ant cultures, SGC was localized primarily in the neuronal cell processes, neurofilaments, and dendrites that emerge from the core of the explants up to 90 mu m, after 24 hr in culture. SGC was also present in the short astr ocytic processes near the core of the explant. SBP-1 was localized mainly i n the granule neuron cell bodies and faintly on cell plasma membranes and p rocesses. Granule neurons, expressing SBP-1, migrated outward in close cont act with the SGC bearing neuronal processes, suggesting interaction between SGC and SEP-I. The neurite outgrowth and cell migration were specifically and severely reduced, in dose-dependent manners, by anti-SGC (HNK-1) and an ti-SBP-1 antibodies and sulfoglucuronyl glycolipid (SGGL). Other irrelevant antibodies and glycolipids had little effect. The results showed that SEP- I was required for neurite outgrowth and that SGC-SBP-1 interaction was imp ortant for cell-cell recognition and cell migration. (C) 2000 Wiley-Liss, I nc.