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Updated: Aug 10, 2026

Two- and Three-Dimensional Live Cell Imaging of DNA Damage Response Proteins
Published on: September 28, 2012
The DNA damage checkpoint response requires histone H2B ubiquitination by Rad6-Bre1 and H3 methylation by Dot1
Michele Giannattasio1, Federico Lazzaro, Paolo Plevani
1Dipartimento di Scienze Biomolecolari e Biotecnologie, Universita' degli Studi di Milano, 20133 Milano, Italy.
Abstract:
The cellular response to DNA lesions entails the recruitment of several checkpoint and repair factors to damaged DNA, and chromatin modifications may play a role in this process. Here we show that in Saccharomyces cerevisiae epigenetic modification of histones is required for checkpoint activity in response to a variety of genotoxic stresses. We demonstrate that ubiquitination of histone H2B on lysine 123 by the Rad6-Bre1 complex, is necessary for activation of Rad53 kinase and cell cycle arrest. We found a similar requirement for Dot1-dependent methylation of histone H3. Loss of H3-Lys(79) methylation does not affect Mec1 activation, whereas it renders cells checkpoint-defective by preventing phosphorylation of Rad9. Such results suggest that histone modifications may have a role in checkpoint function by modulating the interactions of Rad9 with chromatin and active Mec1 kinase.
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