Cellular heredity in haploid cultures of somatic cells. Comprehensive report, April 1975--June 1977. [UV radiation]

Technical Report · Fri Jul 01 04:00:00 EDT 1977

DOI:https://doi.org/10.2172/5134519· OSTI ID:5134519

Freed, J. J.

This report reviews genetic studies carried out since 1975 on a haploid cultured cell line from frog embryos (ICR 2A). Although a single chromosome set would be expected to facilitate recovery of recessive mutants, experiments suggested that cell culture variants might arise through processes more complex than the selection of simple mutational changes. Therefore, the objectives of the work reported here have been to throw light on just how cell culture variants arise in this system. First, we have continued to characterize the ICR 2A line, with emphasis on stability of karyotype and DNA content. Second, we have studied in detail the origin of two classes of drug-resistant variants. Bromodeoxyuridine resistance of the thymidine deficiency type has been shown to arise through sequential loss of two forms of thymidine-phosphorylating enzyme; loss of the second form of enzyme is complex, suggesting that changes more complex than simple recessive mutations may be involved. Another form of resistance, in which tolerance of high levels of bromodeoxyuridine is found in cells that continue to express thymidine kinase, remains under study. Variants resistant to microtubule inhibitors were isolated. It was found that these haploid strains have properties distinguishing them from analogous resistant strains isolated from diploid mammalian cell cultures in other laboratories. In order to understand better how mutagens are involved in the origin of cell culture variants, we have examined the effect of different forms of DNA repair on the frequency of drug-resistant colonies induced by ultraviolet radiation. Preliminary experiments suggest that the frequency of such colonies is greater when repair takes place through (presumably error-prone) dark repair than when (error-free) photoreversal is allowed to occur. Such experiments can determine whether new phenotypes arise from alterations in DNA, and thus whether, in a broad sense, they are likely to be mutational in nature.

• Research Organization: Institute for Cancer Research, Philadelphia, Pa. (USA). Fox Chase Cancer Center
• OSTI ID: 5134519
• Report Number(s): COO-3110-29
• Country of Publication: United States
• Language: English

Related Subjects

550400 -- Genetics
560121* -- Radiation Effects on Cells-- External Source-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMPHIBIANS
ANIMAL CELLS
ANIMALS
ANTIMETABOLITES
ANTIMITOTIC DRUGS
AQUATIC ORGANISMS
AZINES
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BIOLOGY
BROMOURACILS
BUDR
CELL CULTURES
CHROMOSOMES
DNA
DRUGS
ELECTROMAGNETIC RADIATION
EMBRYOS
ENZYMES
FROGS
GENETICS
HAPLOIDY
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
KARYOTYPE
MUTAGENS
MUTANTS
MUTATIONS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC BROMINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PLOIDY
PYRIMIDINES
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
RIBOSIDES
SOMATIC CELLS
THYMIDINE
ULTRAVIOLET RADIATION
URACILS
VERTEBRATES