title: Delayed induction of telomere instability in normal human fibroblast cells by ionizing radiation.
abstract: We examined the delayed induction of telomere instability in hTERT-immortalized normal human fibroblast (BJ1-hTERT) cells exposed to X-rays. BJ1-hTERT cells were irradiated with 2 Gy of X-rays, and chromosome aberrations were analyzed 24 hours after irradiation and in the surviving cells 14 days after X-ray exposure. We found that the X-ray-surviving cells showed an increased frequency of chromatid gaps and breaks and chromosome fragments compared to the control cells. Furthermore, centromere- and telomere-FISH revealed that the frequency of telomere loss and duplication significantly increased in surviving cells compared to the control level. Because no induction of telomere abnormality was observed in cells 24 hours after irradiation, X-irradiation might not affect telomeres directly, but it specifically induces delayed telomere instability in normal human fibroblast cells.
authors.affiliation: Division of Radiation Biology, Department of Radiology and Radiation Biology, Course of Life Sciences and Radiation Research, Graduate School of Biomedical Sciences, Nagasaki University, Japan.
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Ojima
authors.forename: Hiroki
authors.initials: H
authors.lastname: Hamano
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Suzuki
authors.forename: Keiji
authors.initials: K
authors.lastname: Suzuki
authors.forename: Seiji
authors.initials: S
authors.lastname: Kodama
authors.forename: Masami
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics / Q000528:radiation effects; D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects; D043171:Chromosomal Instability / Q000235:genetics / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D005347:Fibroblasts / Q000473:pathology* / Q000528:radiation effects*; D005786:Gene Expression Regulation / Q000528:radiation effects; D006801:Humans; D011829:Radiation Dosage; D011839:Radiation, Ionizing; D016615:Telomere / Q000235:genetics* / Q000528:radiation effects* / Q000648:ultrastructure