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Signaling from Mus81-Eme2-Dependent DNA Damage Elicited by Chk1 Deficiency Modulates Replication Fork Speed and

Hervé Técher1, Stéphane Koundrioukoff1, Sandra Carignon1

  • 1Institut Curie, PSL Research University, CNRS UMR 3244, 75248 Paris Cedex 05, France; Sorbonne Universités, UPMC Univ Paris 06, 75252 Paris Cedex 05, France.

Cell Reports
|January 26, 2016
PubMed

Insights

Mammalian cells lacking ATR or Chk1 show replication issues. Chk1 deficiency causes DNA damage, which drives replication changes, unlike ATR deficiency.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Genetics

Background:

  • Mammalian cells deficient in ATR or Chk1 exhibit replication fork slowing and increased initiation density.
  • The precise mechanisms underlying these replication dynamics in ATR- or Chk1-deficient cells remain poorly understood.

Purpose of the Study:

  • To elucidate the distinct mechanisms by which ATR and Chk1 deficiencies impact DNA replication dynamics.
  • To investigate the role of DNA damage and the DNA Damage Response (DDR) in modulating replication phenotypes.

Main Methods:

  • Utilized deoxyribonucleosides to assess replication phenotypes in Chk1- and ATR-deficient cells.
  • Investigated nuclease-dependent DNA damage formation in Chk1-deficient cells.
  • Examined the effects of inhibiting nucleases (Mus81-Eme2, Mre11) and the ATM pathway on replication phenotypes.

Main Results:

  • Exogenous deoxyribonucleosides ameliorated replication phenotypes in Chk1-deficient cells but not ATR-deficient cells, indicating distinct mechanisms.
  • Chk1 deficiency, but not ATR deficiency, induced nuclease-dependent DNA damage.
  • Inhibiting DNA damage formation or DDR signaling suppressed replication phenotypes in Chk1-deficient cells, establishing damage as a cause, not a consequence.
  • DDR activation was found to reduce replication precursor availability, contributing to fork slowing and backup origin firing.

Conclusions:

  • Replication dynamics modulation in Chk1-deficient cells is driven by DNA damage and subsequent DDR activation.
  • ATR and Chk1 deficiencies impact DNA replication through separate pathways.
  • Reduced precursor availability due to DDR activation is a key factor in replication fork slowing and origin firing in damaged cells.

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