Position of telomeres in nucleus influences length
Telomeres are specialised structures at the ends of chromosomes and protect these from damage much like the plastic caps on a shoelace protect it from fraying. And as anyone who has threaded a shoelace will tell you, it's important that shoelace ends are neither too short nor too long.
A recent paper in Nature Cell Biology from the laboratory of Susan Gasser from the Friedrich Miescher Institute for Biomedical Research has shown that the position of telomeres within the nucleus can influence how long they become. Using the budding yeast, Saccharomyces cerevisiae, the authors showed that telomere localization is influenced by the post-translational modification of telomeric proteins by SUMO. In cells where these proteins were not SUMO modified, because the SUMO-ligase Siz2 was deleted, telomeres detached from their usual location at the nuclear periphery and move to the interior of the nucleus. Subsequently, telomeres became longer.
In addition, the researchers were able to show that cells can use nuclear localisation to promote the restoration of normal telomere length when these telomeres became too short. This study helps to understand how cells organise the location of their genetic material within the nucleus and the significance of such a nuclear compartmentalization.