Biomaterial Database

Enhancement of O6-methylguanine-DNA-methyltransferase activity induced by various treatments in mammalian cells. 1986

P Lefebvre, and F Laval

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.

UI	MeSH Term	Description	Entries
D008769	Methylnitronitrosoguanidine	A nitrosoguanidine derivative with potent mutagenic and carcinogenic properties.	Methylnitrosonitroguanidine,Nitrosomethylnitroguanidine,Nitrosonitromethylguanidine,MNNG,N-Methyl-N'-nitro-N-nitrosoguanidine,N Methyl N' nitro N nitrosoguanidine
D008780	Methyltransferases	A subclass of enzymes of the transferase class that catalyze the transfer of a methyl group from one compound to another. (Dorland, 28th ed) EC 2.1.1.	Methyltransferase
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D001761	Bleomycin	A complex of related glycopeptide antibiotics from Streptomyces verticillus consisting of bleomycin A2 and B2. It inhibits DNA metabolism and is used as an antineoplastic, especially for solid tumors.	BLEO-cell,Blanoxan,Blenoxane,Bleolem,Bleomicina,Bleomycin A(2),Bleomycin A2,Bleomycin B(2),Bleomycin B2,Bleomycin Sulfate,Bleomycins,Bleomycinum Mack,Bléomycine Bellon,BLEO cell,BLEOcell,Bellon, Bléomycine,Mack, Bleomycinum,Sulfate, Bleomycin
D002453	Cell Cycle	The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.	Cell Division Cycle,Cell Cycles,Cell Division Cycles,Cycle, Cell,Cycle, Cell Division,Cycles, Cell,Cycles, Cell Division,Division Cycle, Cell,Division Cycles, Cell
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D002945	Cisplatin	An inorganic and water-soluble platinum complex. After undergoing hydrolysis, it reacts with DNA to produce both intra and interstrand crosslinks. These crosslinks appear to impair replication and transcription of DNA. The cytotoxicity of cisplatin correlates with cellular arrest in the G2 phase of the cell cycle.	Platinum Diamminodichloride,cis-Diamminedichloroplatinum(II),cis-Dichlorodiammineplatinum(II),Biocisplatinum,Dichlorodiammineplatinum,NSC-119875,Platidiam,Platino,Platinol,cis-Diamminedichloroplatinum,cis-Platinum,Diamminodichloride, Platinum,cis Diamminedichloroplatinum,cis Platinum
D004247	DNA	A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).	DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D004611	Ellipticines	Pyrido-CARBAZOLES originally discovered in the bark of OCHROSIA ELLIPTICA. They inhibit DNA and RNA synthesis and have immunosuppressive properties.
D004790	Enzyme Induction	An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.	Induction, Enzyme