Targeted and Non-Targeted Induction of Chromosomal Rearrangements After Exposure to Ionizing Radiation

Abstract

Exposure to ionizing radiation can result in chromosomal rearrangements in a cell cycle dependent manner. This is presumably due to the deposition of energy in the nucleus of the irradiated cell causing DNA double-strand cleavage and the failure of the DNA repair machinery to faithfully restore the integrity of the genetic material. There is also increasing evidence that an irradiated cell can signal to a non-irradiated “bystander” cell and elicit cellular responses, including chromosomal rearrangements, in these non-targeted cells. These signals can be communicated between targeted (irradiated) cells and non-targeted (non-irradiated) cells by both cell-to-cell gap junction communication mechanisms as well as soluble factors secreted into the culture medium. In this chapter we review the evidence for targeted and non-targeted induction of chromosomal rearrangements after exposure to ionizing radiation and speculate about potential mechanisms and their significance in radiation risk assessment.