Discrimination between complete and incomplete chromosome exchanges in X-irradiated human lymphocytes using FISH with pan-centromeric and chromosome specific DNA probes in combination with telomeric PNA probe.
OBJECTIVE
To discriminate precisely between radiation-induced complete and incomplete chromosome exchanges using chromosome painting together with the detection of the centromeres and telomeres in one FISH assay.


METHODS
Human lymphocytes were exposed in vitro to X-rays at a dose of 4 Gy. Chromosome aberrations were analysed using the FISH technique in combination with a whole chromosome-specific DNA probe for chromosome 8, human pan-centromeric DNA and telomeric PNA probes.


RESULTS
The combined FISH assay has improved the resolution of detecting chromosomal exchanges in human lymphocytes. Results indicate that the frequency of observed incomplete exchange patterns was 21% when telomeric signals were ignored during the analysis. When the telomeric signals were included in the analysis a large proportion of apparently incomplete exchange patterns appeared complete and should be re-classified. The percentage of true incomplete exchanges was found to be less than 5%.


CONCLUSIONS
The combination of chromosome painting and the detection of centromeres and telomeres enable unequivocal discrimination between incomplete and complete exchanges. The fraction of true incomplete exchanges observed in X-irradiated human lymphocytes was found to be low in comparison with previous reports in the literature.
Fomina
J
J
MGC, Department of Radiation Genetics and Chemical Mutagenesis, Leiden University Medical Centre, The Netherlands. Fomina@Rullf2.MedFac.LeidenUniv.NL
Darroudi
F
F
Boei
J J
JJ
Natarajan
A T
AT
D002869:Chromosome Aberrations; D020223:Chromosome Painting; D015342:DNA Probes; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000528:radiation effects / Q000648:ultrastructure; D008297:Male; D020135:Peptide Nucleic Acids / Q000235:genetics; D012854:Sister Chromatid Exchange / Q000528:radiation effects*; D016615:Telomere / Q000235:genetics
D015342:DNA Probes; D020135:Peptide Nucleic Acids