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Tumour suppressor ING1b maintains genomic stability upon replication stress
Ronald P C Wong1, Hanyang Lin, Shahram Khosravi
1Department of Dermatology and Skin Science, Jack Bell Research Centre, Vancouver Coastal Health Research Institute, University of British Columbia, Vancouver, British Columbia, ON, Canada V6H 3Z6.
Nucleic Acids Research
|January 14, 2011
Summary
Tumor suppressor ING1b preserves genomic stability by regulating proliferating cell nuclear antigen (PCNA) monoubiquitination. ING1b deficiency impairs DNA lesion bypass, increasing cancer risk.
Area of Science:
- Molecular Biology
- Genetics
- Cancer Research
Background:
- The lesion bypass pathway, regulated by proliferating cell nuclear antigen (PCNA) monoubiquitination, is crucial for resolving DNA replication stalling.
- Genomic instability and cancer development are linked to defects in DNA repair pathways.
- Tumor suppressor p33ING1 (ING1b) deficiency causes hypersensitivity to DNA damaging agents through an uncharacterized mechanism.
Purpose of the Study:
- To elucidate the novel tumor suppressive function of ING1b in maintaining genomic stability during replication stress.
- To investigate the role of ING1b in regulating PCNA monoubiquitination and its impact on DNA lesion bypass.
Main Methods:
- Knockdown of ING1b in cells.
- Assessment of sensitivity to UV irradiation and DNA damaging agents.
- Analysis of PCNA monoubiquitination status.
- Investigation of ING1b's interaction with Rad18 and its role in lesion bypass.
- Evaluation of histone H4 acetylation and chromatin remodeling.
Main Results:
- ING1b knockdown cells exhibit increased sensitivity to UV due to impaired recovery from replication blockage, leading to genomic instability.
- ING1b is essential for Rad18-mediated PCNA monoubiquitination during lesion bypass.
- ING1b-dependent PCNA monoubiquitination is linked to histone H4 acetylation.
- Chromatin remodeling contributes to stalled replication fork stabilization and PCNA monoubiquitination regulation.
Conclusions:
- ING1b plays a critical role in preserving genomic stability by regulating PCNA monoubiquitination during replication stress.
- ING1b's function in lesion bypass is mediated through its regulation of PCNA monoubiquitination and associated chromatin modifications.
- These findings reveal a novel tumor suppressive mechanism involving ING1b, PCNA, and chromatin remodeling, offering potential therapeutic targets for cancer prevention.
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