The ends of linear eukaryotic chromosomes are capped by sequences known as telomeres. Although telomeres are essentially one half of a DNA double-strand break, which is a pathogenic lesion that must be repaired, telomeres do not normally activate DNA damage repair pathways. Here, the three-member MRN complex is shown to serve two roles at the telomere: it protects newly synthesized telomeric ends from repair factors and it promotes a type of fusion repair when the telomere is not functioning properly.
- Yibin Deng
- Xiaolan Guo
- Sandy Chang