TZAP: A telomere-associated protein involved in telomere length control

A protein to trim too-long telomeres Telomeres cap the ends of linear eukaryotic chromosomes. They consist of multiple copies of short DNA repeats. The length of telomeres is important to genome stability; if they become too short, individuals can become prone to cancer and premature aging. Li et al. discovered a protein, TZAP (telomeric zinc finger–associated protein), which instead prevents telomeres from becoming too long (see the Perspective by Lossaint and Lingner). TZAP binds directly to the telomeric DNA repeats, competing with the shelterin complex. It stimulates telomere trimming, preventing aberrantly long telomeres. Science , this issue p. 638 ; see also p. 578