title: Characterization of late-arising chromosome aberrations in human B-cell lines established from alpha-ray- or gamma-ray-irradiated lymphocytes.
abstract: To clarify the characteristics of late-arising (delayed) chromosome aberrations after irradiation in human lymphocytes, 30 B-cell lines were established from the peripheral blood from a healthy adult donor, the lymphocytes of which were exposed to alpha-rays or gamma-rays and then used for experiments. Chromosome aberrations were serially observed at several passages by both conventional cytogenetics and fluorescence in situ hybridization analysis using subtelomere probes. These B-cell lines derived from lymphocytes with a history of radiation exposure had higher percentages of delayed chromosome aberrations, such as dicentrics, rings, endoreduplication, hyperdiploid, hyperploidy, and telomere association. Furthermore, alpha-ray exposure induced higher chromosome instability than gamma-ray exposure, indicating that delayed chromosome aberrations were related with radiation quality. Chromosome instabilities were also observed at the subtelomere. Cell lines showing high chromosome instability had high DNA-PK activity, low expressions of Ku70, p53, and TRF1 proteins after stimulation with radiation. These results indicate that mechanisms underlying delayed chromosome aberrations might be epigenetic, and multiple factors such as defects of DNA-PK, subtelomere, and telomere might be associated.
authors.affiliation: Department of Radiobiology, Institute for Environmental Sciences, Rokkasho, Aomori 039-3213, Japan. kmtanaka@ies.or.jp
authors.forename: Kimio
authors.initials: K
authors.lastname: Tanaka
authors.forename: Tirukalikundram S
authors.initials: TS
authors.lastname: Kumaravel
authors.forename: Shozo
authors.initials: S
authors.lastname: Ihda
authors.forename: Nanao
authors.initials: N
authors.lastname: Kamada
mesh_terms: D000512:Alpha Particles; D034961:Antigens, Nuclear / Q000378:metabolism; D001402:B-Lymphocytes / Q000378:metabolism*; D002460:Cell Line; D043171:Chromosomal Instability; D002869:Chromosome Aberrations; D020732:Cytogenetic Analysis; D051747:DNA-Activated Protein Kinase / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005720:Gamma Rays; D006801:Humans; D000072200:Ku Autoantigen; D008214:Lymphocytes / Q000528:radiation effects*; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D012854:Sister Chromatid Exchange; D019098:Telomerase / Q000378:metabolism; D035321:Telomeric Repeat Binding Protein 1 / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
chemical_list: D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; C495901:TP53 protein, human; D035321:Telomeric Repeat Binding Protein 1; D016159:Tumor Suppressor Protein p53; D051747:DNA-Activated Protein Kinase; D019098:Telomerase; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen