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Article

  • The EMBO Journal (2007) 26, 2707 - 2718
  • doi:10.1038/sj.emboj.7601719

Published online: 10 May 2007

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

Andreas Meier1, Heike Fiegler2, Purificacion Muñoz3, Peter Ellis2, Diane Rigler2, Cordelia Langford2, Maria A Blasco3, Nigel Carter2 and Stephen P Jackson1

  1. The Wellcome Trust and Cancer Research UK Gurdon Institute, Department of Zoology, University of Cambridge, Cambridge, UK
  2. The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
  3. Spanish National Cancer Center (CNIO), Melchor Fernández Almagro no 3, Madrid, Spain

Correspondence to:

Stephen P Jackson, The Wellcome Trust and Cancer Research UK Gurdon Institute, Department of Zoology, University of Cambridge, Tennis Court Road, CB2 1QN Cambridge, UK. Tel.: +44 1223 334 102; Fax: +44 1223 334 089; E-mail: s.jackson@gurdon.cam.ac.uk

Received 6 March 2007; Accepted 19 April 2007

Phosphorylated histone H2AX (gammaH2AX) is generated in nucleosomes flanking sites of DNA double-strand breaks, triggering the recruitment of DNA-damage response proteins such as MDC1 and 53BP1. Here, we study shortened telomeres in senescent human cells. We show that most telomeres trigger gammaH2AX formation, which spreads up to 570 kb into the subtelomeric regions. Furthermore, we reveal that the spreading patterns of 53BP1 and MDC1 are very similar to that of gammaH2AX, consistent with a structural link between these factors. Moreover, different subsets of telomeres signal in different cell lines, with those that signal tending to equate to the shortest telomeres of the corresponding cell line, thus linking telomere attrition with DNA-damage signalling. Notably, we find that, in some cases, gammaH2AX spreading is modulated in a manner suggesting that H2AX distribution or its ability to be phosphorylated is not uniform along the chromosome. Finally, we observe weak gammaH2AX signals at telomeres of proliferating cells, but not in hTERT immortalised cells, suggesting that low telomerase activity leads to telomere uncapping and senescence in proliferating primary cells.

  • Keywords:

    • ChIP-chip,
    • DNA-damage response,
    • H2AX,
    • senescence,
    • telomere