How are sticky chromosomes formed?
Blood lymphocytes in culture were irradiated by gamma-rays 3 h to 30 mn before harvesting. The various induced lesions were analysed, with a particular attention on sticky chromosomes, i.e. radial figures in which chromosomes are not obviously broken, but are linked by a tiny filament. Such anomalies are preferentially induced in mid to late G2-phase. They result from recombinations occurring at nonrandom chromosome regions: junction between hetero- and euchromatin, and telomeric regions. It is proposed that they are formed when double strand breaks are induced while intrachromatidic links have started to be formed in the course of chromosome condensation. If this interpretation is correct, the apparent lack of induced breakage of premitotic chromosomes is artifactual.
Al Achkar
W
W
IPSN, Département de Protection Sanitaire, Fonte-Nay-Aux-Roses, France.
Sabatier
L
L
Dutrillaux
B
B
D002478:Cells, Cultured; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000528:radiation effects*; D005720:Gamma Rays; D006570:Heterochromatin / Q000528:radiation effects; D006801:Humans; D066298:In Vitro Techniques; D007399:Interphase / Q000528:radiation effects; D008214:Lymphocytes / Q000528:radiation effects; D013997:Time Factors
D006570:Heterochromatin