Detection of incomplete exchanges and interstitial fragments in X-irradiated human lymphocytes using a telomeric PNA probe.
OBJECTIVE
The detection of incomplete exchanges and interstitial fragments by fluorescence in situ hybridization using a telomeric peptide nucleic acid (PNA) probe.


METHODS
Isolated human lymphocytes were exposed in vitro to X-rays at a dose of 3 Gy. Aberrations were analysed in the first mitosis after irradiation using a telomeric PNA probe.


RESULTS
After an acute dose of 3 Gy, only about 16% of the cells contained a pair of incomplete chromosome elements with telomeric signals at only one terminal end. Acentric interstitial fragments, lacking telomeric signals, were observed with a frequency of 0.56 per cell, which was very similar to the dicentric frequency (0.61 per cell).


CONCLUSIONS
The low frequency of incompleteness suggests that most of the non-reciprocal interchanges observed using chromosome painting must originate from terminal exchanges rather than from incomplete exchanges. Furthermore, it was estimated that about 78% of excess acentric fragments originate from interstitial fragments and only 22% from terminal fragments.
MGC, Department of Radiation Genetics and Chemical Mutagenesis, Leiden University, The Netherlands.
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D002453:Cell Cycle / Q000528:radiation effects; D002869:Chromosome Aberrations; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D066298:In Vitro Techniques; D007621:Karyotyping; D008214:Lymphocytes / Q000166:cytology / Q000528:radiation effects*; D009838:Oligodeoxyribonucleotides; D015345:Oligonucleotide Probes; D010455:Peptides; D016615:Telomere / Q000528:radiation effects*; D014965:X-Rays
D009838:Oligodeoxyribonucleotides; D015345:Oligonucleotide Probes; D010455:Peptides