The generation and characterization of a rat neural cell line overexpressing the alpha2,6(N) sialyltransferase.

In order to examine the effects of altered protein sialylation on neural cell function, B104 rat neuroblastoma cells were stably transfected with the cDNA coding for alpha2,6(N) sialyltransferase (ST(6)N). Lectin blot analysis of the clones demonstrated an increase in staining of the Sambucus nigra lectin, which detects alpha2,6 linked sialic acid, in parallel with enzyme activity. There was a concomitant decrease in staining by the Maackia amurensis lectin which labels alpha2,3-linked sialic acid, indicating that the individual sialyltransferase enzymes may compete for penultimate galactose acceptor sites. While there was an initial increase in protein-bound sialic acid in parallel with enzyme activity, the sialylation of the cells was demonstrated to be saturable. There was an inverse relationship between cell adhesion to a fibronectin substrate and ST(6)N activity suggesting that the negatively charged sugar acts to modulate cell-substrate interaction. These cells will provide an ideal model system with which to further investigate the effect of altered sialic acid on neural cell function.