Crosstalk between chromatin structure, nuclear compartmentalization, and telomere biology

Telomeres are heterochromatic structures essential for the maintenance of genomic stability and the proliferative potential of human somatic cells. A minimal length of telomeric DNA repeats and proper binding of specialized proteins are required for the maintenance of telomere structure and function. Activation of telomere length maintenance mechanisms is considered a hallmark of cancer, while attrition of telomeres is a known contributor to the phenotypes associated with the aging process. However, the molecular mechanisms responsible for telomere homeostasis are not completely understood. Compelling data indicates that the epigenetic status of telomeric and subtelomeric chromatin also plays a role in the regulation of telomere biology. In addition, genomic regions are not randomly distributed within the nucleus, but rather compartmentalized into spatial and temporal domains whose functional implications for the cell are only beginning to be unraveled. Recent studies indicate that alterations in some of the mechanisms responsible for nuclear organization associate with defects in chromatin structure. These observations suggest a link between these two processes, raising the question of whether nuclear compartmentalization of telomeres might also impact on telomere biology.