title: Gene dosage and complementation analysis of ataxia telangiectasia lymphoblastoid cell lines assayed by induced chromosome aberrations.
abstract: An approach of general applicability to mammalian radiosensitive mutants has been used in the analysis of gene dosage and complementation in ataxia telangiectasia (A-T). Thymidine residues in DNA of one parental lymphoblastoid cell line were substituted with bromodeoxyuridine before fusion with a second parental cell line, to allow differential staining of the two sets of chromosomes. Following gamma-irradiation, induced chromosome aberrations were scored in diploid and homokaryon cells from each parental line as well as in heterokaryons. Four complementation groups were ascertained among 7 A-T cell lines. Analysis of heterokaryons formed between appropriate combinations of normal, A-T homozygote and A-T heterozygote cells, gave a quantitative measure of gene dosage and demonstrated increasing radiosensitivity with increasing numbers of A-T alleles.
mesh_terms: D001260:Ataxia Telangiectasia / Q000235:genetics*; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000528:radiation effects; D004260:DNA Repair; D005720:Gamma Rays; D005816:Genetic Complementation Test; D006579:Heterozygote; D006720:Homozygote; D006801:Humans