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Functional human telomeres are recognized as DNA damage in G2 of the cell cycle

Ramiro E Verdun1, Laure Crabbe, Candy Haggblom

  • 1The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.

Molecular Cell
|November 26, 2005
PubMed

Insights

Telomeres recruit DNA damage response proteins during the G2 phase, suggesting they are unprotected. This localized response is crucial for telomere protection and cell cycle integrity.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Genetics

Background:

  • Telomeres are protective caps at chromosome ends.
  • DNA damage response proteins are known to interact with telomeres, but their role is unclear.
  • Telomere dysfunction is linked to aging and cancer.

Purpose of the Study:

  • To investigate the role of DNA damage response proteins at telomeres in primary cells.
  • To understand the functional significance of these interactions for telomere maintenance.
  • To elucidate the mechanism of telomere protection during the cell cycle.

Main Methods:

  • Cell cycle analysis of telomeric protein recruitment.
  • Assessment of telomere accessibility to modifying enzymes.
  • Investigating the effects of MRN complex degradation and ATM inhibition on telomere function.

Main Results:

  • Telomeres in telomerase-negative primary cells recruit Mre11, phosphorylated NBS1, and ATM during G2 phase.
  • This recruitment is associated with POT1 release and increased telomere accessibility.
  • Disruption of the MRN complex or ATM inhibition caused telomere dysfunction.

Conclusions:

  • A localized DNA damage response at telomeres after replication is essential.
  • This response recruits processing machinery for chromosome end protection.
  • These findings highlight a novel mechanism for maintaining telomere integrity.

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