Enhancement of O6-methylguanine-DNA-methyltransferase activity induced by various treatments in mammalian cells
The O6-methylguanine-DNA-methyltransferase (methyltransferase) activity was determined in a rat hepatoma cell line after treatment with ultraviolet or gamma-irradiation, heat treatment, or incubation with cis-diamminedichloroplatinum(II),2-methyl-9-hydroxyellipticinium, or bleomycin. The assay measured the removal of O6-methylguanine from 3H-alkylated DNA by cellular extracts. The results show that 48 h after the various treatments, the methyltransferase activity is increased by 2- to 5-fold. This increase is due to de novo specific protein synthesis. It is not related to a modification of the cell cycle parameters, as a similar enhancement is observed in plateau-phase cells treated with ionizing radiations or cis-dichlorodiammineplatinum(II). The increase of the methyltransferase activity measured using an alkylated substrate represents an actual increase of the active molecules in the cells, as the mutation frequency is much lower in cells treated with N-methyl-N'-nitro-N-nitrosoguanidine 48 h after an irradiation (3 Gy) than in nonirradiated cells. This induction of the methyltransferase was not observed in Chinese hamster ovary cells after gamma-irradiation, and therefore it does not seem to occur in cells which have a low constitutive level of O6-methylguanine repair.
- Research Organization:
- Institut Gustave-Roussy, Villejuif, France
- OSTI ID:
- 7133149
- Journal Information:
- Cancer Res.; (United States), Journal Name: Cancer Res.; (United States) Vol. 11; ISSN CNREA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Increase of O6-methylguanine-DNA-methyltransferase and N3-methyladenine glycosylase RNA transcripts in rat hepatoma cells treated with DNA-damaging agents
Sensitivity of human cell strains having different abilities to repair O6-methylguanine in DNA to inactivation by alkylating agents including chloroethylnitrosoureas
Related Subjects
Cells
& Tissue Culture
560200 -- Thermal Effects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMINES
ANIMAL CELLS
ANIMALS
AROMATICS
AZAARENES
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CELL CYCLE
CHO CELLS
DNA
DNA POLYMERASES
ELECTROMAGNETIC RADIATION
ENZYME ACTIVITY
ENZYME INDUCTION
ENZYMES
GAMMA RADIATION
GENE REGULATION
GUANINE
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
IONIZING RADIATIONS
MAMMALS
NUCLEIC ACIDS
NUCLEOTIDYLTRANSFERASES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
POLYMERASES
PROTEINS
PURINES
RADIATION EFFECTS
RADIATIONS
RATS
RODENTS
TEMPERATURE EFFECTS
TRANSFERASES
TUMOR CELLS
ULTRAVIOLET RADIATION
VERTEBRATES