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SET8 localization to chromatin flanking DNA damage is dependent on RNF168 ubiquitin ligase
Stanimir Dulev1, Sichun Lin1, Qingquan Liu1
1Department of Medical Biophysics, University of Toronto, Toronto, Canada.
Cell Cycle (Georgetown, Tex.)
|November 26, 2019
Summary
The DNA damage response involves recruiting repair proteins to double-strand breaks (DSBs). This study reveals RNF168 ubiquitin ligase mediates SET8 methyltransferase recruitment to DSBs, a crucial step for DNA repair.
Area of Science:
- Molecular Biology
- Cellular Biology
- Genetics
Background:
- The DNA damage response (DDR) orchestrates the recruitment of chromatin remodelers and repair factors to DNA double-strand breaks (DSBs).
- Proteins like 53BP1 are critical for DSB repair, and their localization depends on ubiquitin ligases (e.g., RNF168) and methyltransferases (e.g., SET8).
Purpose of the Study:
- To investigate the precise mechanism by which RNF168 and SET8 contribute to 53BP1 recruitment at DSBs.
- To determine if RNF168 and SET8 utilize the same pathways for their localization to DSBs.
Main Methods:
- Depletion of cellular ubiquitin via proteasome inhibition.
- Knockdown of RNF8 and RNF168.
- Assessment of RNF168 and SET8 localization to DNA damage sites.
- Analysis of RNF168 and SET8 complex formation in vivo.
Main Results:
- RNF168 mediates the recruitment of SET8 to DSBs.
- Depletion of ubiquitin or knockdown of RNF8/RNF168 prevents SET8 localization to DNA damage.
- RNF168 and SET8 form stable complexes in vivo, suggesting a direct interaction.
Conclusions:
- RNF168 is essential for recruiting SET8 to DSBs, clarifying a key step in the DDR pathway.
- A model is proposed where SET8 accumulates at DSBs via tethering to proteins that recognize specific chromatin modifications, facilitated by RNF168.
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