Role of protein synthesis in the repair of sublethal x-ray damage in a mutant Chinese hamster ovary cell line

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:6936365

Yezzi, M J

A temperature-sensitive mutant for protein synthesis, CHO-TSH1, was compared to the wild-type cell, CHO-SC1, in single- and split-radiation-dose schemes. When the cultures were incubated at 40/sup 0/C for 2 hrs before a first dose and maintained at 40/sup 0/C during a 2 hr dose fractionation interval, repair of radiation damage was reduced in the mutant compared to the wild type. These observations implied that a pool of proteins was involved in the repair of sublethal X-ray damage. The effect of diminished repair under conditions of inhibition of protein synthesis was found to be cell-cycle dependent in survival studies with synchronized mutant cell populations. Repair was found to be almost completely eliminated if the temperature sequence described above was applied in the middle of the DNA synthetic phase. Distinct perturbations in the cell-cycle progression were noted following heat alone or heat with radiation. A delay in the progression of synchronized G/sub 1/-phase and S-phase cells was demonstrated autoradiographically after inhibition of protein synthesis. In addition, treated S-phase cells showed a transient increase in the percent labelled cells after the cells were returned to their normal growth temperature of 35/sup 0/C. This observation was suggestive of an unusual pattern of DNA synthesis during the recovery period. Split-dose experiments were done using incubation with cycloheximide to chemically inhibit protein synthesis. Both the chemical and thermal inhibition of protein synthesis substantiate its necessity for the repair of sublethal damage.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 6936365
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CYCLOHEXIMIDE
BIOLOGICAL EFFECTS
DNA
BIOLOGICAL REPAIR
HAMSTERS
OVARIES
PROTEINS
BIOSYNTHESIS
X RADIATION
CELL CULTURES
MUTANTS
ANIMALS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
BIOLOGICAL RECOVERY
BODY
DRUGS
ELECTROMAGNETIC RADIATION
FEMALE GENITALS
FUNGICIDES
GONADS
IONIZING RADIATIONS
MAMMALS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PESTICIDES
RADIATIONS
RECOVERY
REPAIR
RODENTS
SYNTHESIS
VERTEBRATES
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture