Tissue‐ and developmental stage‐specific forms of a neural cell surface antigen linked to differences in glycosylation of a common polypeptide.

We have previously identified a cell surface glycoprotein of the mouse nervous system named brain cell surface protein‐2 (BSP‐2). Here we report that this antigen is not a single, discrete entity, but a family of antigenically and structurally related molecules. Three components of 180, 140, and 120 K were characteristic for more mature nervous tissues. Adult cerebral cortex contained the 140‐K and 120‐K antigens, adult spinal cord only the 120‐K, and dorsal root ganglia from young mice mainly the 180‐K component. Very different forms of the antigen that migrated as a diffuse zone from 180‐250‐K in SDS‐polyacrylamide gels were found in immature nervous tissues. A molecule different from the previous ones was found in a neuroblastoma line. Evidence is presented that the structural diversity of BSP‐2 is due to differences in glycosylation. This result indicates that cell type‐ and developmental stage‐specific glycoprotein patterns previously found in the nervous system may in part be due to different glycosylation of identical polypeptides. The finding that a neural cell surface protein may be glycosylated in different ways has important implications for the generation of cell surface specificity.