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 α-mannose residues is dramatically reduced (≤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 cytotoxicity of concanavalin A (Con A); (d) an increased ability to bind125I-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, resistant clones from each of two complementary CHO auxotrophic 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.
Original language | English (US) |
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Pages (from-to) | 208-215 |
Number of pages | 8 |
Journal | In Vitro |
Volume | 12 |
Issue number | 3 |
DOIs | |
State | Published - Mar 1976 |
Externally published | Yes |
Keywords
- complementation
- glycosyl transferases
- lectins
- membrane mutants
- somatic cell genetics
ASJC Scopus subject areas
- Developmental Biology
- Clinical Biochemistry
- Cell Biology