Characterisation of homologous recombination induced by replication inhibition in mammalian cells

Yannick Saintigny (1) , Fabien Delacote (2) , Guillaume Vares (2, 3) , Fabrice Petitot (2) , Sarah Lambert (2) , Dietrich Averbeck (4) , Bernard Lopez (2)

1 LERA - Laboratoire d'Etudes de la Réparation de l'ADN
2 LMR - Laboratoire d'étude des Mécanismes de la recombinaison
3 GCC - Génotoxicologie et cycle cellulaire
4 Stress génotoxiques et cancer

To analyze relationships between replication and homologous recombination in mammalian cells, we used replication inhibitors to treat mouse and hamster cell lines containing tandem repeat recombination substrates. In the ®rst step, few double-strand breaks (DSBs) are produced, recombination is slightly increased, but cell lines defective in non-homologous end-joining (NHEJ) affected in ku86 (xrs6) or xrcc4 (XR-1) genes show enhanced sensitivity to replication inhibitors. In the second step, replication inhibition leads to coordinated kinetics of DSB accumulation, Rad51 foci formation and RAD51-dependent gene conversion stimulation. In xrs6 as well as XR-1 cell lines, Rad51 foci accumulate more rapidly compared with their respective controls. We propose that replication inhibition produces DSBs, which are ®rst processed by the NHEJ; then, following DSB accumulation, RAD51 recombination can act.

Domaines: Cancer

Yannick Saintigny, Fabien Delacote, Guillaume Vares, Fabrice Petitot, Sarah Lambert, et al.. Characterisation of homologous recombination induced by replication inhibition in mammalian cells. EMBO Journal, 2001, 20 (14), pp.3861-3870. ⟨10.1093/emboj/20.14.3861⟩. ⟨cea-01938127⟩