The non-random repositioning of whole chromosomes and individual gene loci in interphase nuclei and its relevance in disease, infection, aging, and cancer

The genomes of a wide range of different organisms are non-randomly organized within interphase nuclei. Chromosomes and genes can be moved rapidly, with direction, to new non-random locations within nuclei upon a stimulus such as a signal to initiate differentiation, quiescence or senescence, or also the application of heat or an infection with a pathogen. It is now becoming increasingly obvious that chromosome and gene position can be altered in diseases such as cancer and other syndromes that are affected by changes to nuclear architecture such as the laminopathies. This repositioning seems to affect gene expression in these cells and may play a role in progression of the disease. We have some evidence in breast cancer cells and in the premature aging disease Hutchinson-Gilford Progeria that an aberrant nuclear envelope may lead to genome repositioning and correction of these nuclear envelope defects can restore proper gene positioning and expression in both disease situations.Although spatial positioning of the genome probably does not entirely control expression of genes, it appears that spatio-epigenetics may enhance the control over gene expression globally and/or is deeply involved in regulating specific sets of genes. A deviation from normal spatial positioning of the genome for a particular cell type could lead to changes that affect the future health of the cell or even an individual.