Quantitation of DNA repair capacities of human tumor cells by estimation of transfer of DNA adducts to repair proteins.
The repair of O6-methylguanine produced in DNA by alkylating agents is accomplished by a unique lesion reversal mechanism which recognizes the methyl group and transfers it to itself in a suicide reaction. Much of what we know about the importance of O6-methylguanine-DNA methyltransferase repair in human cells comes from the study of Mer- tumor cell strains which are deficient in transferase activity. The human transferase has a preference for repair of methyl groups, but will also act on other substrates. Assays for transferase activity detect either the loss of O6-methylguanine from DNA or the appearance of methylated protein. A new assay detects the recovery of a restriction site in a synthetic polymer following demethylation. Inhibition of transferase activity can be produced in cells by several methods.
D002460:Cell Line; D004260:DNA Repair / Q000187:drug effects*; D004273:DNA, Neoplasm / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors; D004926:Escherichia coli; D006801:Humans; D008780:Methyltransferases / Q000494:pharmacology*; D019853:O(6)-Methylguanine-DNA Methyltransferase
D004273:DNA, Neoplasm; D004791:Enzyme Inhibitors; D008780:Methyltransferases; D019853:O(6)-Methylguanine-DNA Methyltransferase