Signaling from Mus81-Eme2-Dependent DNA Damage Elicited by Chk1 Deficiency Modulates Replication Fork Speed and Origin Usage
Hervé Técher,
Stéphane Koundrioukoff,
Sandra Carignon,
Therese Wilhelm,
Gaël A. Millot,
Bernard S. Lopez,
Olivier Brison,
Michelle Debatisse
Affiliations
Hervé Técher
Institut Curie, PSL Research University, CNRS UMR 3244, 75248 Paris Cedex 05, France; Sorbonne Universités, UPMC Univ Paris 06, 75252 Paris Cedex 05, France
Stéphane Koundrioukoff
Institut Curie, PSL Research University, CNRS UMR 3244, 75248 Paris Cedex 05, France; Sorbonne Universités, UPMC Univ Paris 06, 75252 Paris Cedex 05, France
Sandra Carignon
Institut Curie, PSL Research University, CNRS UMR 3244, 75248 Paris Cedex 05, France; Sorbonne Universités, UPMC Univ Paris 06, 75252 Paris Cedex 05, France
Therese Wilhelm
Institut Curie, PSL Research University, CNRS UMR 3244, 75248 Paris Cedex 05, France; Sorbonne Universités, UPMC Univ Paris 06, 75252 Paris Cedex 05, France
Gaël A. Millot
Institut Curie, PSL Research University, CNRS UMR 3244, 75248 Paris Cedex 05, France; Sorbonne Universités, UPMC Univ Paris 06, 75252 Paris Cedex 05, France
Bernard S. Lopez
Institut de Cancérologie Gustave Roussy, CNRS UMR 8200 and Université Paris Sud, 94805 Villejuif, France
Olivier Brison
Institut Curie, PSL Research University, CNRS UMR 3244, 75248 Paris Cedex 05, France; Sorbonne Universités, UPMC Univ Paris 06, 75252 Paris Cedex 05, France
Michelle Debatisse
Institut Curie, PSL Research University, CNRS UMR 3244, 75248 Paris Cedex 05, France; Sorbonne Universités, UPMC Univ Paris 06, 75252 Paris Cedex 05, France; Corresponding author
Summary: Mammalian cells deficient in ATR or Chk1 display moderate replication fork slowing and increased initiation density, but the underlying mechanisms have remained unclear. We show that exogenous deoxyribonucleosides suppress both replication phenotypes in Chk1-deficient, but not ATR-deficient, cells. Thus, in the absence of exogenous stress, depletion of either protein impacts the replication dynamics through different mechanisms. In addition, Chk1 deficiency, but not ATR deficiency, triggers nuclease-dependent DNA damage. Avoiding damage formation through invalidation of Mus81-Eme2 and Mre11, or preventing damage signaling by turning off the ATM pathway, suppresses the replication phenotypes of Chk1-deficient cells. Damage and resulting DDR activation are therefore the cause, not the consequence, of replication dynamics modulation in these cells. Together, we identify moderate reduction of precursors available for replication as an additional outcome of DDR activation. We propose that resulting fork slowing, and subsequent firing of backup origins, helps replication to proceed along damaged templates. : Técher et al. show that modulation of DNA replication dynamics in Chk1-deficient mammalian cells is the consequence of DNA damage arising through unscheduled Mus81-Eme2 and Mre11 activation. Signaling of this damage by the ATM pathway impedes fork progression through dNTP shortage.
