Telomeres and double-strand breaks: trying to make ends meet.

Eukaryotic cells encounter two types of DNA ends: telomeres, the natural ends of linear chromosomes, and double-strand breaks, resulting from DNA damage or normal chromosomal processes such as meiotic or V(D)J recombination. These two termini have long been seen as functionally distinct, based on whether they are resistant to fusion with other ends or instead are acted upon by the DNA-repair machinery. However, a series of recent papers has shown that members of a set of proteins that are crucial for the rejoining of DNA strand breaks are also required for normal telomere function, raising new questions about how these two types of termini maintain their functional distinction.