title: CHO cells selected for phytohemagglutinin and con A resistance are defective in both early and late stages of protein glycosylation.
abstract: The lipid-linked and asparagine-linked oligosaccharides of two lectin-resistant and one parental Chinese hamster ovary (CHO) cell line have been compared by glycosidase digestion and gel filtration analysis of radiolabeled glycopeptides and oligosaccharides. The additional glycosylation defect in a double mutant cell line (CHO-PhaRConAR) selected from a phytohemagglutinin-resistant single mutant cell line (CHO-PhaR) for resistance to concanavalin A has been identified as a block in the synthesis of the lipid-linked oligosaccharide precursor, resulting in a structure with seven instead of the normal nine mannose units. Both the CHO-PhaRConR and CHO-PhaR cells were completely blocked in the synthesis of complex, acidic type oligosaccharides because of a previously demonstrated deficiency in a particular N--acetylglucosamine transferase activity. In addition, an altered collection of neutral type oligosaccharides (Man4-7GlcNAc2) accumulated in the glycoproteins of the double mutant.
mesh_terms: D000818:Animals; D001216:Asparagine; D002236:Carbohydrate Conformation; D002460:Cell Line; D003208:Concanavalin A / Q000494:pharmacology*; D006224:Cricetinae; D004351:Drug Resistance; D005260:Female; D037102:Lectins / Q000494:pharmacology*; D009154:Mutation; D009844:Oligosaccharides / Q000032:analysis / Q000378:metabolism*; D010053:Ovary; D011506:Proteins / Q000378:metabolism*
chemical_list: D037102:Lectins; D009844:Oligosaccharides; D011506:Proteins; D003208:Concanavalin A; D001216:Asparagine