title: O6-Methylguanine removal by competent and incompetent human lymphoblastoid lines from the same male individual.
abstract: Two cell lines, one proficient (Mex+) and one deficient (Mex-) in the ability to remove O6-methylguanine, have been isolated by Epstein-Barr virus-mediated transformation of a single blood sample obtained from a normal human male. Extracts of untreated cells differ in their O6-methylguanine transferase (methyl acceptor protein) activity. Although both lines arise from the same individual, they show great difference in their sensitivities to the toxic action of N-methyl-N'-nitro-N-nitrosoguanidine. Chromosome counts of the strains reveal a modal number of 46 for both. Neither X-inactivation nor a gross abnormality in chromosome number can be the cause of the difference between the two lines.
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000302:isolation & purification; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002869:Chromosome Aberrations; D006147:Guanine / Q000031:analogs & derivatives* / Q000302:isolation & purification; D006801:Humans; D007621:Karyotyping; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology
chemical_list: D008769:Methylnitronitrosoguanidine; C025946:3-methyladenine; D006147:Guanine; C008449:O-(6)-methylguanine; D000225:Adenine