Phenotypic expression time of mutagen-induced 6-thioguanine resistance in Chinese hamster ovary cells (CHO/HGPRT system): expression in division-arrested cell cultures

Journal Article · Thu Dec 31 23:00:00 EST 1981 · Environ. Mutagen.; (United States)

DOI:https://doi.org/10.1002/em.2860040402· OSTI ID:6137073

O'Neill, J P; Machanoff, R; Hsie, A W

The phenotypic expression time of ethyl methanesulfonate (EMS) induced 6-thioguanine-resistant mutants was studied with Chinese hamster ovary cells in culture (CHO/HGPRT system). After mutagen treatment of exponential phase cultures, the cells were maintained either in the exponential phase through subculture in medium containing 5% dialyzed fetal bovine serum (FBS) or in a nondividing viable state by use of medium containing 0-1% dialyzed FBS. The time course of expression of the 6-thioguanine-resistant phenotype was similar with both exponential phase division-arrested cultures showing maximum expression by 9 days after mutagen event is fixed, the expression of the mutant phenotype does not require continued cell division since it occurs in division-arrested cultures. These results also suggest that both dilution of pre-existing hypoxanthine-guanine phosphoribosyl transferase (HGPRT) enzyme by cell division and turnover by protein degradation are involved in the phenotypic expression. These results separate genetic damage and phenotypic expression in a temporal sense, and point out the need to consider the mechanisms responsible for each process involved in the induction and expression of mutations.

• Research Organization: Oak Ridge National Lab., TN
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6137073
• Journal Information: Environ. Mutagen.; (United States), Journal Name: Environ. Mutagen.; (United States) Vol. 4; ISSN ENMUD
• Country of Publication: United States
• Language: English

Related Subjects

550301 -- Cytology-- Tracer Techniques
550401* -- Genetics-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINES
ANIMAL CELLS
BIOLOGICAL EFFECTS
BIOSYNTHESIS
CHO CELLS
EMS
ENZYMES
ESTERS
GENETIC EFFECTS
GLYCOSYL TRANSFERASES
HYPOXANTHINE PHOSPHORIBOSYLTRANSFERASE
LABELLED COMPOUNDS
MUTAGENS
MUTATION FREQUENCY
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PENTOSYL TRANSFERASES
PHENOTYPE
PROTEINS
SULFONIC ACID ESTERS
SYNTHESIS
TIME DEPENDENCE
TRANSFERASES
TRITIUM COMPOUNDS