Surface proteins of cultured mouse cerebellar cells

Surface proteins of cultured monolayer cells from embryonic and early postnatal C57BL/6J mouse cerebella were identified by a lactoperoxidase-catalysed 131iodine labelling technique. Major iodinated polypeptides have molecular weights of approximately 200, 145, 120, 100, 85, 65, 50, and 30 x 10(3) (P200, P145,...) as estimated by sodium dodecylsulphate polyacrylamide gel electrophoresis. Membrane glycoproteins, of apparent molecular weights 200, 145, 100, 85, and 50 x 10(3), are detected by biosynthetic labelling with [3H]fucose. The two major iodinated proteins are the glycoproteins P200 and P145. P145 is released from the cells into the medium together with other surface proteins. No changes in the patterns of labelled cerebellar cell surface proteins are detectable between embryonic day 17 and postnatal day 10. A pattern similar to the one seen with cerebellum is obtained with embryonic day 12 and 17 cerebral cortex. Cultured retinal cells from 2-day-old mice, skin fibroblasts, and L-cells display a distinctly different pattern, which does not contain P145 as a major iodinated component. In granule cell-enriched fractions of cerebellar cells the two glycoproteins P200 and P145 are proportionately increased, while three proteins, P100, P85, and P50, are more abundant in the glial cell-enriched fraction. These three polypeptides are also enriched in cells obtained from staggerer mutant mice. An antiserum against 4-day-old cerebellar cells (anti-NS-4) precipitates the 145 and 200 x 10(3) molecular weight proteins, from lysates of both embryonic cerebral and postnatal cerebellar cells. From lysates of mouse retinal cells, anti-NS-4 antiserum precipitates two proteins with molecular weights of 140 and 210 x 10(3).