Characterization of multilocus lesions in human cells exposed to X radiation and radon

Journal Article · Mon Jan 01 00:00:00 EST 1996 · Radiation Research

DOI:https://doi.org/10.2307/3579192· OSTI ID:478295

Chaudhry, M A; Jiang, Q; Ricanati, M; Horng, M F; Evans, H H ^[1]

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1. Case Western Reserve Univ., Cleveland, OH (United States)

Human TK6 lymphoblasts were exposed to X radiation or radon, and thymidine kinase negative (TK{sup -/-}) mutants were selected, isolated and harvested for analysis of structural changes in the TK gene. A large majority (82%) of the radon-induced mutants, 74% of the X-radiation-induced mutants and 45% of the spontaneous mutants lost the entire active TK allele. To analyze these mutants further we measured the loss of heterozygosity at several loci neighboring the TK locus on chromosome 17q. A greater proportion (61%) of the radon-induced mutants than X-radiation-induced or spontaneous mutants harbored the smaller lesions involving the TK allele alone or extending from the TK locus to one or both of the closest neighboring sequences tested. Further, 21% of the X-radiation-induced mutants but only 5% of the radon-induced mutants lost heterozygosity at the col1A1 locus, 31 Mb from the TK gene. These results are in agreement with a recent analysis of radon- and X-radiation-induced lesions inactivating the HPRT gene of TK6 cells, in which we reported that a lower percentage of radon- than X-radiation-induced mutants showed lesions extending to markers 800 kb or more from the HPRT gene on the X chromosome. In the present study, we observed that the percentage of slowly growing and very slowly growing TK{sup -/-} mutants was greater after treatment with radon than after treatment with X radiation, regardless of the type of lesion present. It is possible, therefore, that the radon-induced lesions are complex and/or less easily repaired, leading to slow growth in a large proportion of the surviving mutant cells. 36 refs., 6 figs., 2 tabs.

• Sponsoring Organization: USDOE
• DOE Contract Number: FG02-88ER60658
• OSTI ID: 478295
• Journal Information: Radiation Research, Vol. 145, Issue 1; Other Information: PBD: Jan 1996
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
RADON
RADIATION DOSES
X RADIATION
PHOSPHOTRANSFERASES
GENE MUTATIONS
GENETIC RADIATION EFFECTS
GENETIC MAPPING
MUTATION FREQUENCY
DNA SEQUENCING
GENE RECOMBINATION
DELAYED RADIATION EFFECTS
HUMAN CHROMOSOME 17
RADIATION INDUCED MUTANTS
GROWTH
CELL CYCLE
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL REPAIR
DNA
DNA REPAIR
STRAND BREAKS
THYMIDINE
BIOLOGICAL MARKERS
RBE