Biomaterial Database

Quantitation of O6-methylguanine-DNA methyltransferase in HeLa cells. 1983

R S Foote, and B C Pal, and S Mitra

A synthetic DNA polymer containing [8-3H]O6-methylguanine (m6G) was used as a substrate to assay the in situ demethylation of the alkylated base by an activity in HeLa cell extracts. The repair activity appears to be similar to the O6-methylguanine-DNA methyltransferase of E. coli and to be inactivated by reaction with the substrate. Extracts of a methylation-repair proficient (Mer+) cell strain, HeLa CCL2, were found to contain m6G repair activity equivalent to approx. 100 000 molecules of methyltransferase per cell, assuming that each molecule can demethylate one m6G residue. No activity could be detected in the extract of a repair deficient (Mer-) cell strain, HeLa S3, and there is no evidence of an inhibitor of repair activity in this strain.

UI	MeSH Term	Description	Entries
D008745	Methylation	Addition of methyl groups. In histo-chemistry methylation is used to esterify carboxyl groups and remove sulfate groups by treating tissue sections with hot methanol in the presence of hydrochloric acid. (From Stedman, 25th ed)	Methylations
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
D004260	DNA Repair	The removal of DNA LESIONS and/or restoration of intact DNA strands without BASE PAIR MISMATCHES, intrastrand or interstrand crosslinks, or discontinuities in the DNA sugar-phosphate backbones.	DNA Damage Response
D006147	Guanine
D006367	HeLa Cells	The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for, among other things, VIRUS CULTIVATION and PRECLINICAL DRUG EVALUATION assays.	Cell, HeLa,Cells, HeLa,HeLa Cell
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D019853	O(6)-Methylguanine-DNA Methyltransferase	An enzyme that transfers methyl groups from O(6)-methylguanine, and other methylated moieties of DNA, to a cysteine residue in itself, thus repairing alkylated DNA in a single-step reaction. EC 2.1.1.63.	Methylated-DNA-Protein-Cysteine S-Methyltransferase,O(6)-AGT,O(6)-Methylguanine Methyltransferase,DNA Repair Methyltransferase I,DNA Repair Methyltransferase II,Guanine-O(6)-Alkyltransferase,O(6)-Alkylguanine-DNA Alkyltransferase,O(6)-MeG-DNA Methyltransferase,O(6)-Methylguanine DNA Transmethylase,Methylated DNA Protein Cysteine S Methyltransferase,S-Methyltransferase, Methylated-DNA-Protein-Cysteine