Histone H3 Lysine 56 Acetylation and the Response to DNA Replication Fork Damage

Abstract

In Saccharomyces cerevisiae, histone H3 lysine 56 acetylation (H3K56ac) occurs in newly synthesized histones that are deposited throughout the genome during DNA replication. Defects in H3K56ac sensitize cells to genotoxic agents, suggesting that this modification plays an important role in the DNA damage response. However, the links between histone acetylation, the nascent chromatin structure, and the DNA damage response are poorly understood. Here we report that cells devoid of H3K56ac are sensitive to DNA damage sustained during transient exposure to methyl methanesulfonate (MMS) or camptothecin but are only mildly affected by hydroxyurea. We demonstrate that, after exposure to MMS, H3K56ac-deficient cells cannot complete DNA replication and eventually segregate chromosomes with intranuclear foci containing the recombination protein Rad52. In addition, we provide evidence that these phenotypes are not due to defects in base excision repair, defects in DNA damage tolerance, or a lack of Rad51 loading at sites of DNA damage. Our results argue that the acute sensitivity of H3K56ac-deficient cells to MMS and camptothecin stems from a failure to complete the repair of specific types of DNA lesions by recombination and/or from defects in the completion of DNA replication.

ACKNOWLEDGMENTS

We thank David Lydall (University of Newcastle), Maria Pia Longhese (University of Milan), Hocine Mankouri, and Ian Hickson (University of Copenhagen) for valuable technical advice.

This work was supported by grants from the Danish Natural Science Research Council (http://en.fi.dk/), the Alfred Benzon Foundation (http://www.benzon-foundation.dk/), and the Villum Kann Rasmussen Foundation (http://www.vkrf.org/vkrf_home.php) to M. Lisby. P. Pasero was funded by the Agence Nationale de la Recherche (http://www.agence-nationale-recherche.fr/) and the Fondation pour la Recherche Médicale (http://www.frm.org/). P. Maddox and A. Verreault were funded by the Canadian Cancer Society Research Institute (FRN-018450) (http://www.cancer.ca/research/) and the Canadian Institutes of Health Research (FRN-79392) (http://www.cihr-irsc.gc.ca/), respectively. The Institute for Research in Immunology and Cancer is supported by infrastructure funds from the Canadian Centre for Excellence in Commercialization and Research, the Canadian Foundation for Innovation, and the Fonds de la Recherche en Santé du Québec.