Ku acts in a unique way at the mammalian telomere to prevent end joining

Hsin Ling Hsu, David Gilley, Sanjeev A. Galande, M. Prakash Hande, Beth Allen, Sahn Ho Kim, Gloria C. Li, Judith Campisi, Terumi Kohwi-Shigematsu, David J. Chen

Research output: Contribution to journalArticlepeer-review

278 Scopus citations


Telomeres are specialized DNA/protein structures that act as protective caps to prevent end fusion events and to distinguish the chromosome ends from double-strand breaks. We report that TRF1 and Ku form a complex at the telomere. The Ku and TRF1 complex is a specific high-affinity interaction, as demonstrated by several in vitro methods, and exists in human cells as determined by coimmunoprecipitation experiments. Ku does not bind telomeric DNA directly but localizes to telomeric repeats via its interaction with TRF1. Primary mouse embryonic fibroblasts that are deficient for Ku80 accumulated a large percentage of telomere fusions, establishing that Ru plays a critical role in telomere capping in mammalian cells. We propose that Ku localizes to internal regions of the telomere via a high-affinity interaction with TRF1. Therefore, Ku acts in a unique way at the telomere to prevent end joining.

Original languageEnglish (US)
Pages (from-to)2807-2812
Number of pages6
JournalGenes and Development
Issue number22
StatePublished - Nov 15 2000


  • Ku
  • TRF1
  • Telomere

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology


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