Chromatin stiffening underlies enhanced locus mobility after DNA damage in budding yeast. (10th July 2017)

• Record Type: Journal Article
• Authors: Herbert, Sébastien; Brion, Alice; Arbona, Jean‐Michel; Lelek, Mickaël; Veillet, Adeline; Lelandais, Benoît; Parmar, Jyotsana; Fernández, Fabiola García; Almayrac, Etienne; Khalil, Yasmine; Birgy, Eleonore; Fabre, Emmanuelle; Zimmer, Christophe
• Is Part Of: EMBO journal. Volume 36:Number 17(2017)
• Page Start: 2595
• Page End: 2608
• Publication Date: 2017-07-10
• Subjects: chromatin dynamics -- chromatin structure -- DNA damage -- polymers -- yeast; Molecular biology -- Periodicals; 572.805
• DOI: 10.15252/embj.201695842
• Languages: English
• ISSNs: 0261-4189

Abstract

Abstract: DNA double‐strand breaks (DSBs) induce a cellular response that involves histone modifications and chromatin remodeling at the damaged site and increases chromosome dynamics both locally at the damaged site and globally in the nucleus. In parallel, it has become clear that the spatial organization and dynamics of chromosomes can be largely explained by the statistical properties of tethered, but randomly moving, polymer chains, characterized mainly by their rigidity and compaction. How these properties of chromatin are affected during DNA damage remains, however, unclear. Here, we use live cell microscopy to track chromatin loci and measure distances between loci on yeast chromosome IV in thousands of cells, in the presence or absence of genotoxic stress. We confirm that DSBs result in enhanced chromatin subdiffusion and show that intrachromosomal distances increase with DNA damage all along the chromosome. Our data can be explained by an increase in chromatin rigidity, but not by chromatin decondensation or centromeric untethering only. We provide evidence that chromatin stiffening is mediated in part by histone H2A phosphorylation. Our results support a genome‐wide stiffening of the chromatin fiber as a consequence of DNA damage and as a novel mechanism underlying increased chromatin mobility. Synopsis: Live cell tracking of yeast chromatin loci allows analysis of chromosome dynamic alteration in response to DNA breaks, suggesting global chromatin stiffening upon genotoxic stress. Fluorescence microscopy measures distances between 16 pairs of chromatin loci and tracks the motion of multiple loci on the right arm of chromosome IV. Intrachromosomal distance distributions agree with polymer models and reflect centromeric stretching. DNA damage by prolonged exposure to Zeocin increases chromatin subdiffusion and intrachromosomal distances. Polymer modeling and super‐resolution imaging support global chromatin stiffening as a cause for increased mobility. H2A phosphorylation is part of the molecular mechanism of chromatin stiffening. Abstract : Live tracking of chromatin loci shows that genotoxic stress and subsequent H2A phosphorylation are associated with genome‐wide intrachromosomal distances increases.