Virtual radiation biophysics: implications of nuclear structure.
The non-random positioning of chromosome territories (CTs) in lymphocyte cell nuclei has raised the question whether systematic chromosome-chromosome associations exist which have significant influence on interchange rates. In such a case the spatial proximity of certain CTs or even of clusters of CTs is expected to increase the respective exchange yields significantly, in comparison to a random association of CTs. In the present study we applied computer simulated arrangements of CTs to calculate interchange frequencies between all heterologous CT pairs, assuming a uniform action of the molecular repair machinery. For the positioning of CTs in the virtual nuclear volume we assumed a) a statistical, and b) a gene density-correlated arrangement. The gene density-correlated arrangement regards the more experimentally observed interior localization of gene-rich and the more peripheral positioning of gene-poor CTs. Regarding one-chromosome yields, remarkable differences for single CTs were observed taking into account the gene density-correlated distribution of CTs.
Kreth
G
G
Kirchhoff Institute for Physics, INF 227 Heidelberg, Germany. gkreth@kip.uni-heidelberg.de
Finsterle
J
J
Cremer
C
C
D055592:Biophysical Phenomena; D001703:Biophysics; D002467:Cell Nucleus / Q000528:radiation effects* / Q000648:ultrastructure; D002478:Cells, Cultured / Q000528:radiation effects / Q000648:ultrastructure; D002843:Chromatin / Q000528:radiation effects / Q000648:ultrastructure; D002869:Chromosome Aberrations; D019457:Chromosome Breakage; D002877:Chromosomes, Human / Q000528:radiation effects / Q000648:ultrastructure; D003198:Computer Simulation; D004260:DNA Repair; D006801:Humans; D008214:Lymphocytes / Q000528:radiation effects / Q000648:ultrastructure; D008957:Models, Genetic; D011853:Radiobiology; D014584:User-Computer Interface
D002843:Chromatin