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Interplay between ATM and ATR in the regulation of common fragile site stability

E Ozeri-Galai1, M Schwartz, A Rahat

  • 1Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem, Israel.

Oncogene
|October 16, 2007
PubMed

Insights

The ataxia-telangiectasia mutated (ATM) protein helps maintain fragile site stability during replication stress, particularly when ATR is absent. Both ATM and ATR pathways regulate fragile site expression via Chk1 phosphorylation.

Area of Science:

  • Genetics
  • Molecular Biology
  • Cellular Biology

Background:

  • Common fragile sites are genomic regions susceptible to breakage during replication stress.
  • These sites are implicated in chromosomal instability and cancer development.
  • DNA damage response proteins like ATR and Chk1 are known regulators of fragile site stability.

Purpose of the Study:

  • To investigate the role of ataxia-telangiectasia mutated (ATM) in regulating common fragile site stability.
  • To elucidate the interplay between ATM and ATR pathways in response to replication stress.

Main Methods:

  • Induction of replication stress to observe fragile site expression.
  • Assessment of DNA fragmentation and ATM phosphorylation at double-strand breaks (DSBs).
  • Analysis of ATM and ATR roles in fragile site stability, including in knockout conditions.

Main Results:

  • Replication stress induces DNA fragmentation and ATM recruitment to DSBs.
  • ATM contributes to fragile site stability, especially in the absence of ATR.
  • ATM activation during replication stress is independent of ATR.
  • Both ATR and ATM phosphorylate Chk1, suggesting a shared regulatory mechanism.

Conclusions:

  • ATM plays a crucial role in maintaining fragile site stability under replication stress.
  • The interplay between ATM and ATR pathways is critical for managing replication stress and fragile site integrity.
  • Chk1 phosphorylation by both ATM and ATR highlights a converging pathway for fragile site regulation.

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