Journal Article

H2B Mono-ubiquitylation Facilitates Fork Stalling and Recovery during Replication Stress by Coordinating Rad53 Activation and Chromatin Assembly

Hung, Shih-Hsun, Gay, Sophie, Devys, Didier, Lai, Mong Sing, Wu, Meng-Ying, Kao, Cheng-Fu, Wright, Duncan Edward, Hsiao, Wei-Chun, Marjavaara, Lisette, Tseng, Hsin-Yi, Lin, Chia-Yeh, Wang, Chen-Yi, Hsu, Guoo-Shyng W., Chabes, Andrei

2014

Overview

The influence of mono-ubiquitylation of histone H2B (H2Bub) on transcription via nucleosome reassembly has been widely documented. Recently, it has also been shown that H2Bub promotes recovery from replication stress; however, the underling molecular mechanism remains unclear. Here, we show that H2B ubiquitylation coordinates activation of the intra-S replication checkpoint and chromatin re-assembly, in order to limit fork progression and DNA damage in the presence of replication stress. In particular, we show that the absence of H2Bub affects replication dynamics (enhanced fork progression and reduced origin firing), leading to γH2A accumulation and increased hydroxyurea sensitivity. Further genetic analysis indicates a role for H2Bub in transducing Rad53 phosphorylation. Concomitantly, we found that a change in replication dynamics is not due to a change in dNTP level, but is mediated by reduced Rad53 activation and destabilization of the RecQ helicase Sgs1 at the fork. Furthermore, we demonstrate that H2Bub facilitates the dissociation of the histone chaperone Asf1 from Rad53, and nucleosome reassembly behind the fork is compromised in cells lacking H2Bub. Taken together, these results indicate that the regulation of H2B ubiquitylation is a key event in the maintenance of genome stability, through coordination of intra-S checkpoint activation, chromatin assembly and replication fork progression.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Biochemistry, Molecular Biology / Biology and life sciences / Cell Cycle Proteins - genetics / Cell Cycle Proteins - metabolism / Checkpoint Kinase 2 - genetics / Checkpoint Kinase 2 - metabolism / Chromatin / Chromatin Assembly and Disassembly / DNA damage / DNA Replication / Genetic aspects / Genetic research / Genomics / Histone-Lysine N-Methyltransferase - genetics / Histone-Lysine N-Methyltransferase - metabolism / Histones / Histones - metabolism / Hydroxyurea - pharmacology / Life Sciences / Molecular Chaperones - genetics / Molecular Chaperones - metabolism / Mutation / Nucleosomes - metabolism / Protein-Serine-Threonine Kinases - genetics / Protein-Serine-Threonine Kinases - metabolism / RecQ Helicases - genetics / RecQ Helicases - metabolism / Saccharomyces cerevisiae - drug effects / Saccharomyces cerevisiae - genetics / Saccharomyces cerevisiae Proteins - genetics / Saccharomyces cerevisiae Proteins - metabolism / Ubiquitin / Ubiquitination / Yeast