Baby-hamster kidney (BHK) cells were grown continuously in long-term monolayer culture in the presence of Swainsonine, an inhibitor of alpha-mannosidase II, a processing enzyme involved in glycoprotein biosynthesis. The asparagine-linked oligosaccharides (N-glycans) were isolated from Pronase-digested cells by gel filtration, ion-exchange chromatography and affinity chromatography on concanavalin A—Sepharose and lentil lectin—Sepharose. The major N-glycans, analysed by 500 MHz 1H-n.m.r. spectroscopy, were identified as hybrid structures containing five mannose residues and neutral high-mannose N-glycans. The major hybrid species contained a core-substituted fucose alpha(1–6) residue and a NeuNAc alpha(2–3)Gal beta(1–4)GlcNAc terminal sequence; smaller amounts of non-sialylated and non-fucosylated hybrid structures were also detected. Swainsonine-treated cells also produced neutral oligosaccharides containing a single reducing N-acetylglucosamine residue substituted with polymannose sequences. The glycopeptide composition of Swainsonine-treated BHK cells resembles closely that of the ricin-resistant BHK cell mutant, RicR21 [P. A. Gleeson, J. Feeney and R. C. Hughes (1985) Biochemistry 24, 493-503], except the hybrid structures of RicR21 cells contain three, not five, mannose residues. Like RicR21 cells, Swainsonine-treated BHK cells showed a greatly increased resistance to ricin cytotoxicity, but not to modeccin, another galactose-binding lectin. These effects were readily reversed on removal of Swainsonine and growth in normal medium.
Properties of baby-hamster kidney (BHK) cells treated with Swainsonine, an inhibitor of glycoprotein processing. Comparison with ricin-resistant BHK-cell mutants
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L Foddy, J Feeney, R C Hughes; Properties of baby-hamster kidney (BHK) cells treated with Swainsonine, an inhibitor of glycoprotein processing. Comparison with ricin-resistant BHK-cell mutants. Biochem J 1 February 1986; 233 (3): 697–706. doi: https://doi.org/10.1042/bj2330697
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