Perturbation of nuclear architecture by long-distance chromosome interactions

The nuclear architecture is disrupted by long-distance chromosome interactions that cause stochastic transcriptional silencing of genes that are present near heterochromatin (position-effect variegation). In the Drosophila embryonic nuclei, a heterochromatic insertion at the brown locus is spatially isolated from other heterochromatin. During larval development, this insertion physically associates with other heterochromatic regions on the same chromosome in a stochastic manner. The frequency of long distance interactions is highest in the interphase nuclei.