Fragility in the 14q21q translocation region

Abstract

Aphidicolin (APC)-induced chromosomal breakage was analyzed for women representing three generations of a single family and carrying a Robertsonian translocation rob(14q21q). Fluorescence in situ hybridization (FISH) analysis confirmed the dicentric constitution of the derived chromosome and indicated the absence of β-satellite signal at the translocation region. Per-individual analysis of metaphases from APC-treated peripheral blood lymphocyte cultures identified significantly nonrandom chromosomal breakage at the translocation region in all three individuals examined. The APC-inducible fragility at the 14q21q translocation region suggests that this rearrangement was the result of chromosomal mutation at fragile site(s) in the progenitor chromosomes, or that this fragility was the result of the fusion of nonfragile progenitor chromosomes.

Hot spots of DNA double-strand breaks and genomic contacts of human rDNA units are involved in epigenetic regulation

“…In humans, nucleolar organizer regions (NOR) bearing chromosomes undergo translocations more frequently than other chromosomes ( Therman et al, 1989 ; Denison et al, 2002 ). The data might suggest, on one hand, the presence of hot spots of double-strand breaks (DSBs) inside rDNA, and, on the other hand, the close proximity of rDNA units to chromatin regions possessing DSBs in different chromosomes ( Misteli, 2010) .…”