Analysis of radiation-induced chromosomal aberrations using telomeric and centromeric PNA probes.
OBJECTIVE
To generate dose-response curves for X-ray-induced chromosomal aberrations analysed in human blood lymphocytes using telomeric and centromeric peptide nucleic acid (PNA) probes.


METHODS
Isolated human lymphocytes were X-irradiated with doses of 0, 1, 2, 3, 4 and 6 Gy. Aberrations were analysed in the first post-irradiation metaphases using telomeric and centromeric PNA probes.


RESULTS
Similar to the dose-response curves for the yield of dicentrics and centric rings, the dose-response curves for interstitial fragments and incomplete elements (derived from either terminal deletions or incomplete exchanges) follow a linear-quadratic function. Furthermore, it was estimated that 76% of excess acentric fragments originate from complete exchanges (interstitial deletions) and only 24% from incomplete exchanges or terminal deletions.


CONCLUSIONS
Interstitial fragments form a major class of radiation-induced chromosomal aberrations. They are induced about half as frequently as dicentrics over the whole dose range investigated. The comparable trend of the dose-response curve for the different aberrations, including incomplete elements, indicates that all detected aberrations are formed by a similar underlying mechanism. It also suggests that the ratio between non- or incomplete repair (leading to open ends of broken chromosomes) and incorrect repair (leading to exchange aberrations) is independent of dose.
Boei
J J
JJ
MGC, Department of Radiation Genetics and Chemical Mutagenesis, Leiden University Medical Center, The Netherlands. Boei@Rullf2.MedFac.LeidenUniv.NL
Vermeulen
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Natarajan
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D002503:Centromere; D002869:Chromosome Aberrations; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008214:Lymphocytes / Q000528:radiation effects / Q000648:ultrastructure; D015341:Nucleic Acid Probes; D016615:Telomere; D014965:X-Rays
D015341:Nucleic Acid Probes