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Nucleic Acids Res. 2015 Mar 11;43(5):2603-14. doi: 10.1093/nar/gkv104. Epub 2015 Feb 17.

CHK1-driven histone H3.3 serine 31 phosphorylation is important for chromatin maintenance and cell survival in human ALT cancer cells.

Author information

1
Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia.
2
Institute of Basic Medical Sciences, and Norwegian Center for Stem Cell Research, Faculty of Medicine, University of Oslo, Oslo 0317, Norway.
3
Stem Cell Epigenetics Laboratory, Murdoch Childrens Research Institute, Flemington Road, Parkville, Victoria 3052, Australia.
4
Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia lee.wong@monash.edu.

Abstract

Human ALT cancers show high mutation rates in ATRX and DAXX. Although it is well known that the absence of ATRX/DAXX disrupts H3.3 deposition at heterochromatin, its impact on H3.3 deposition and post-translational modification in the global genome remains unclear. Here, we explore the dynamics of phosphorylated H3.3 serine 31 (H3.3S31ph) in human ALT cancer cells. While H3.3S31ph is found only at pericentric satellite DNA repeats during mitosis in most somatic human cells, a high level of H3.3S31ph is detected on the entire chromosome in ALT cells, attributable to an elevated CHK1 activity in these cells. Drug inhibition of CHK1 activity during mitosis and expression of mutant H3.3S31A in these ALT cells result in a decrease in H3.3S31ph levels accompanied with increased levels of phosphorylated H2AX serine 139 on chromosome arms and at the telomeres. Furthermore, the inhibition of CHK1 activity in these cells also reduces cell viability. Our findings suggest a novel role of CHK1 as an H3.3S31 kinase, and that CHK1-mediated H3.3S31ph plays an important role in the maintenance of chromatin integrity and cell survival in ALT cancer cells.

PMID:
25690891
PMCID:
PMC4357709
DOI:
10.1093/nar/gkv104
[Indexed for MEDLINE]
Free PMC Article

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