Higher-order structure of interphase chromosomes and radiation-induced chromosomal exchange aberrations.
OBJECTIVE
To discuss the effects of chromosome structure on the inter- and intrachromosomal exchanges in the framework of the model, which argues that the higher-order chromosome structure contains 10-30 Mbp loop clusters (micelles).


CONCLUSIONS
Intermicelle contacts determine exchange-type chromosome aberrations. Ratios of inter- to intrachromosomal exchanges calculated in the model are similar to the experimental data (literature) for human lymphocytes and flat fibroblasts. The frequency of interchanges is affected by nuclear shape; this might explain the greater number of interchanges observed in 3-D spherical lymphocytes vs. that in 2-D flat fibroblasts. Chromosome configuration (linear vs. folded Rab1) affects the pattern of micelle contacts. The model predicts that chromosomes in haploid Tradescantia microspores have the folded Rab1 orientation; this explains quantitatively the low value of the ratio of dicentrics to centric rings observed in these cells.
Ostashevsky
J Y
JY
Department of Radiation Oncology, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA. ostasj23@hscbklyn.edu
D002869:Chromosome Aberrations; D002875:Chromosomes / Q000502:physiology / Q000528:radiation effects*; D005347:Fibroblasts / Q000528:radiation effects; D017343:Genes, Plant / Q000502:physiology / Q000528:radiation effects; D006801:Humans; D007399:Interphase / Q000528:radiation effects*; D008214:Lymphocytes / Q000528:radiation effects; D008823:Micelles; D008954:Models, Biological; D012854:Sister Chromatid Exchange
D008823:Micelles