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Updated: Nov 27, 2025
Quantification of γH2AX Foci in Response to Ionising Radiation
Published on: April 6, 2010
ADP-ribosylation of histone variant H2AX promotes base excision repair
Qian Chen1, Chunjing Bian1, Xin Wang1
1Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope Medical Center, Duarte, CA, USA.
Abstract:
Optimal DNA damage response is associated with ADP-ribosylation of histones. However, the underlying molecular mechanism of DNA damage-induced histone ADP-ribosylation remains elusive. Herein, using unbiased mass spectrometry, we identify that glutamate residue 141 (E141) of variant histone H2AX is ADP-ribosylated following oxidative DNA damage. In-depth studies performed with wild-type H2AX and the ADP-ribosylation-deficient E141A mutant suggest that H2AX ADP-ribosylation plays a critical role in base excision repair (BER). Mechanistically, ADP-ribosylation on E141 mediates the recruitment of Neil3 glycosylase to the sites of DNA damage for BER. Moreover, loss of this ADP-ribosylation enhances serine-139 phosphorylation of H2AX (γH2AX) upon oxidative DNA damage and erroneously causes the accumulation of DNA double-strand break (DSB) response factors. Taken together, these results reveal that H2AX ADP-ribosylation not only facilitates BER repair, but also suppresses the γH2AX-mediated DSB response.
Insights
Histone ADP-ribosylation at glutamate 141 of H2AX is crucial for DNA repair. This modification facilitates base excision repair (BER) and suppresses the DNA double-strand break (DSB) response.
Area of Science:
- Molecular Biology
- Epigenetics
- DNA Repair Mechanisms
Background:
- Histone ADP-ribosylation is vital for DNA damage response.
- The precise molecular mechanisms of DNA damage-induced histone ADP-ribosylation are not fully understood.
Purpose of the Study:
- To elucidate the molecular mechanism of DNA damage-induced histone ADP-ribosylation.
- To investigate the role of H2AX ADP-ribosylation in DNA repair pathways.
Main Methods:
- Unbiased mass spectrometry to identify ADP-ribosylated histone residues.
- Biochemical assays using wild-type H2AX and E141A mutant.
- Analysis of DNA repair factor recruitment and phosphorylation events.
Main Results:
- Glutamate 141 (E141) of histone H2AX is ADP-ribosylated upon oxidative DNA damage.
- H2AX ADP-ribosylation is critical for efficient base excision repair (BER) by recruiting Neil3 glycosylase.
- Loss of H2AX ADP-ribosylation enhances H2AX serine-139 phosphorylation (γH2AX) and promotes DNA double-strand break (DSB) response factor accumulation.
Conclusions:
- H2AX ADP-ribosylation at E141 is a key regulator of DNA damage response.
- This modification facilitates BER pathway and concurrently suppresses the γH2AX-mediated DSB response, highlighting a dual role in maintaining genome stability.
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