Cited by 320Telomeres, Telomerase, and SenescenceDNA Repair MechanismsDNA and Nucleic Acid Chemistry

Ku70 stimulates fusion of dysfunctional telomeres yet protects chromosome ends from homologous recombination

Celli, Giulia B., Denchi, Eros Lazzerini, de Lange, Titia·2006·Nature Cell Biology

Abstract

Ku70-Ku80 heterodimers promote the non-homologous end-joining (NHEJ) of DNA breaks and, as shown here, the fusion of dysfunctional telomeres. Paradoxically, this heterodimer is also located at functional mammalian telomeres and interacts with components of shelterin, the protein complex that protects telomeres. To determine whether Ku contributes to telomere protection, we analysed Ku70(-/-) mouse cells. Telomeres of Ku70(-/-) cells had a normal DNA structure and did not activate a DNA damage signal. However, Ku70 repressed exchanges between sister telomeres - a form of homologous recombination implicated in the alternative lengthening of telomeres (ALT) pathway. Sister telomere exchanges occurred at approximately 15% of the chromosome ends when Ku70 and the telomeric protein TRF2 were absent. Combined deficiency of TRF2 and another NHEJ factor, DNA ligase IV, did not elicit this phenotype. Sister telomere exchanges were not elevated at telomeres with functional TRF2, indicating that TRF2 and Ku70 act in parallel to repress recombination. We conclude that mammalian chromosome ends are highly susceptible to homologous recombination, which can endanger cell viability if an unequal exchange generates a critically shortened telomere. Therefore, Ku- and TRF2-mediated repression of homologous recombination is an important aspect of telomere protection.

Integrity signals

Registry

Crossref · 10.1038/ncb1444

Cites

35 of 35 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

This paper’s full text isn’t openly available, so its claims and self-check weren’t run. The registry and citation checks still apply.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • When telomeres are compromised by loss of TRF2, their repair is carried out by c-NHEJ.

    “By contrast, when telomeres are compromised through the loss of TRF2, their repair is carried out by c-NHEJ80–82.”

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Authors
Celli, G. B., Denchi, E. L., & de Lange, T.
Affiliations
Rockefeller University (US)
Venue
Nature Cell Biology
Published
2006-07-16
Volume
8
Issue
8
Pages
885-890
ISSN
  • 1465-7392 (ISSN-L)
  • 1476-4679
OpenAlex
W1990507848
Cited by
320
References
35
Citations by year
2026: 3 · 2025: 6 · 2024: 10 · 2023: 11 · 2022: 7 · 2021: 8 · 2020: 15 · 2019: 10 · 2018: 13 · 2017: 12 · 2016: 8 · 2015: 15 · 2014: 22 · 2013: 30 · 2012: 17
FWCI
15.65
Type
journal article
Language
en
Open access
closed
Locations
  • Nature Cell Biology (publishedVersion)
  • PubMed (publishedVersion)
Funders
National Institute of General Medical Sciences (GM 49046)
Topics
  • Health Sciences › Medicine › Physiology › Telomeres, Telomerase, and Senescence
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › DNA Repair Mechanisms
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › DNA and Nucleic Acid Chemistry
Keywords
Ku70, Ku80, telomere protection, homologous recombination, alternative lengthening of telomeres, TRF2, shelterin, non-homologous end joining, DNA ligase IV, telomere dysfunction
MeSH terms
Ku Autoantigen, DNA Ligase ATP, Animals, DNA Repair, DNA-Binding Proteins, Microscopy, Fluorescence, Models, Biological, DNA Ligases, Recombination, Genetic, Sister Chromatid Exchange, Immunoblotting, Signal Transduction, Telomere, Protein Serine-Threonine Kinases, Mice, Knockout, Chromosomes, Mammalian, Antigens, Nuclear, Telomeric Repeat Binding Protein 2, Mice, Checkpoint Kinase 2

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review