The expression of concanavalin a binding glycoproteins during the development of cerebellar granule neurons in vitro

We present data on the expression of Concanavalin A (ConA) binding glycoproteins by granule cell enriched cultures derived from 8 day postnatal rat cerebellum. Time course studies were conducted over a 12 day culture period. ConA binding glycoproteins were localized on the cell bodies and fibres of the granule neurons using fluorescence microscopy. The fluorescence intensity increased between 4 and 12 days in vitro. Quantitative studies on the capacity of live cells to bind (125)I-iodinated ConA showed that there was a significant increase in the amount of lectin bound between 4 and 8 days in vitro. However, in contrast to previous results on the developing cerebellum in vivo [Zanetta et al. (1978) Brain Res.142, 301-319.], there was no decline in binding capacity after 8 days in culture. Glycoproteins expressed by these cells were analysed by staining SDS polyacrylamide gels with [(125)I]ConA. A large number of lectin binding proteins were observed which spread over a wide range of molecular weights. Only minor changes were detected in the profile of [(125)I]ConA binding glycoproteins with the maturation of the cells in culture. The comparison of the findings on granule cells developing in culture and in vivo suggested that an interaction between granule cell axons and their normal target neurons is involved in the regulation of the ConA binding protein content in the cerebellum.