Nerve growth factor-inducible, large external (NILE) glycoprotein in developing rat cerebral cells in culture

Fetal rat cerebral cells underwent neuronal differentiation in culture. This process was accompanied by distinct changes in the cellular glycoprotein pattern. The incorporation of [3H]-fucose into two proteins of apparent molecular weights of 30,000 and 60,000 daltons was significantly decreased and specific developmental changes were observed in a group of glycoproteins with high molecular weights (150,000-250,000 dalton). By means of indirect immunoprecipitation one of them was identified as NILE gp (nerve growth factor-inducible large external) glycoprotein (200,000 dalton), a marker of central and peripheral neurons. Its developmental expression on neurons of dissociated rat cerebral cultures was studied using the indirect immunofluorescence technique and compared to the fluorescent-labeling pattern of other neuronal markers. Neurons expressing NILE gp were detected as early as after one day in culture. No preferential staining of neurites versus cell bodies was observed. Two classes of NILE gp-positive cell-type, whereas the other group was represented by larger, more spindle-shaped neurons with a limited number of neuritic processes. In most cases one of these neuritic processes was preferentially labeled. Astroglia cells, as identified by immunolabeling with antisera against the glial acidic fibrillary protein, were observed to develop and mature after the first week in culture. NILE-positive neurons were found to be positioned in close association with glial cell processes.