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CometChip: A High-throughput 96-Well Platform for Measuring DNA Damage in Microarrayed Human Cells
10:59

CometChip: A High-throughput 96-Well Platform for Measuring DNA Damage in Microarrayed Human Cells

Published on: October 18, 2014

Spreading of mammalian DNA-damage response factors studied by ChIP-chip at damaged telomeres

Andreas Meier1, Heike Fiegler, Purificacion Muñoz

  • 1The Wellcome Trust and Cancer Research UK Gurdon Institute, Department of Zoology, University of Cambridge, Cambridge, UK.

The EMBO Journal
|May 12, 2007
PubMed

Insights

Shortened telomeres in senescent cells trigger DNA damage signals, with gammaH2AX spreading into subtelomeric regions. This telomere attrition links to DNA damage signaling, impacting cell proliferation and senescence.

Area of Science:

  • Cellular Biology
  • Genetics
  • Molecular Biology

Background:

  • Phosphorylated histone H2AX (gammaH2AX) marks DNA double-strand breaks, recruiting DNA-damage response proteins like MDC1 and 53BP1.
  • Senescence in human cells is associated with telomere shortening.

Purpose of the Study:

  • To investigate the relationship between shortened telomeres and DNA damage signaling in senescent human cells.
  • To characterize the spreading patterns of gammaH2AX, MDC1, and 53BP1 at shortened telomeres.

Main Methods:

  • Analysis of gammaH2AX formation and spreading in senescent human cells.
  • Comparison of spreading patterns of gammaH2AX, MDC1, and 53BP1.
  • Investigation of telomere signaling in different cell lines and correlation with telomere length.
  • Assessment of gammaH2AX signals in proliferating and immortalized cells.

Main Results:

  • Most telomeres in senescent cells trigger gammaH2AX formation, spreading up to 570 kb into subtelomeric regions.
  • Spreading patterns of 53BP1 and MDC1 closely resemble gammaH2AX spreading, suggesting a structural link.
  • Telomere signaling varies between cell lines, with shortest telomeres typically initiating the signal, linking telomere attrition to DNA damage response.
  • gammaH2AX spreading is modulated, indicating non-uniform H2AX distribution or phosphorylation capacity.
  • Weak gammaH2AX signals are observed at telomeres of proliferating cells but absent in hTERT immortalized cells.

Conclusions:

  • Telomere attrition in senescent cells activates a DNA damage response pathway involving gammaH2AX, MDC1, and 53BP1.
  • The observed patterns suggest a direct link between telomere shortening and the initiation of DNA damage signaling.
  • Low telomerase activity may lead to telomere uncapping and subsequent senescence in proliferating primary cells.

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