title: Selection and characterization of Chinese hamster ovary cells resistant to the cytotoxicity of lectins.
abstract: Chinese hamster ovary (CHO) cells selected in a single step for resistance to the cytotoxicity of the lectin from red kidney beans (PHA) behave as authentic somatic cell mutants. The PHA-resistant (Phar) phenotype is stable in the absence of selection; its frequency in a sensitive-population is increased several-fold by mutagenesis; and it behaves recessively in somatic cell hybrids. The activity of a specific glycosyl transferase which transfers N-acetylglucosamine (GlcNAc) to terminal alpha-mannose residues is dramatically reduced (less than or equal to 5% of the activity detected in wild-type CHO cells) in several independent PhaR clones. These clones also exhibit (a) a decreased ability to bind [125I]-PHA; (b) a marked resistance to the cytotoxicity of wheat germ agglutinin (WGA), Ricin (RIC) and Lens culinaris agglutinin (LCA); (c) a 4- to 5-fold increased sensitivity to the cytoxocity of concanavalin A (Con A); (d) an increased ability to bind 125I-Con A; and (e) decreased surface galactose residues - all properties consistent with the specific loss of the GlcNAc transferase activity. The lectins WGA, RIC, LCA and Con A have also been used to select, in a single step, resistance closes from each of two complementary CHO auxitrophic lines. These lectin-resistant clones have been characterized by their ability to survive cytotoxic doses of PHA, Con A, WGA, RIC, or LCA, and 4-5 "lectin-resistance" phenotypes have been demonstrated. Complementation data is being sought by somatic cell hybridization. Preliminary results show that two phenotypically-distinct Con AR mutants are complementary in that hybrid cells formed between them exhibit wild-type sensitivity to Con A.
mesh_terms: D002460:Cell Line; D002462:Cell Membrane; D002999:Clone Cells; D003208:Concanavalin A / Q000494:pharmacology; D004351:Drug Resistance; D005020:Ethyl Methanesulfonate / Q000494:pharmacology; D005808:Genes, Recessive; D005964:Glucosyltransferases / Q000378:metabolism; D006822:Hybrid Cells; D037102:Lectins / Q000378:metabolism / Q000494:pharmacology*; D009154:Mutation; D010641:Phenotype; D011955:Receptors, Drug; D013329:Structure-Activity Relationship
chemical_list: D037102:Lectins; D011955:Receptors, Drug; D003208:Concanavalin A; D005020:Ethyl Methanesulfonate; D005964:Glucosyltransferases