title: Selectivity of the excision of alkylation products in a xeroderma pigmentosum-derived lymphoblastoid line.
abstract: Lymphoblastoid cell derived from a complementation group C xeroderma patient were unable to remove 06-methyl guanine residues formed in DNA by treatment of cells with low concentration of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). The xeroderma cells were competent in their ability to excise 3-methyl adenine adducts. MNNG treatment induced excision repair in the xeroderma line and in addition the treatment resulted in the presence of numerous single-strand breaks in the DNA. The single gene, UV-excision-defective mutants of Escherichia coli, uvrA and uvrB, are able to excise MNNG-induced 06-methyl guanine adducts indicating that excision of this compound is not due to operation of UV endonuclease system.
mesh_terms: D002460:Cell Line; D004247:DNA / Q000378:metabolism; D004260:DNA Repair; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology; D009153:Mutagens; D010641:Phenotype; D014983:Xeroderma Pigmentosum / Q000235:genetics*
chemical_list: D009153:Mutagens; D008769:Methylnitronitrosoguanidine; D004247:DNA