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Human NTH1 physically interacts with p53 and proliferating cell nuclear antigen
Masaki Oyama1, Mitsuo Wakasugi, Takashi Hama
1Laboratory of Molecular Human Genetics, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192, Japan.
Biochemical and Biophysical Research Communications
|September 11, 2004
Summary
Human NTH1 enzyme repairs oxidative DNA damage by removing thymine glycol (Tg). Researchers found that p53 and XPG proteins directly interact with NTH1 and enhance its DNA repair activity.
Area of Science:
- Biochemistry
- Molecular Biology
- Genetics
Background:
- Thymine glycol (Tg) is a major oxidative DNA lesion.
- Human NTH1 is a bifunctional enzyme crucial for base excision repair (BER).
- NTH1 removes Tg lesions, initiating the BER pathway.
Purpose of the Study:
- To identify factors interacting with human NTH1.
- To investigate the functional impact of these interactions on NTH1 activity.
- To explore potential links between NTH1-mediated repair and other cellular processes.
Main Methods:
- Pull-down assays using GST-NTH1 fusion protein.
- Interaction studies with recombinant proteins (FLAG-tagged XPG, PCNA, and (His)6-tagged p53).
- Enzyme activity assays to measure NTH1 glycosylase/AP lyase activity.
Main Results:
- GST-NTH1 precipitated proliferating cell nuclear antigen (PCNA), p53, and XPG from cell extracts.
- Direct protein-protein interactions were confirmed between NTH1 and recombinant p53, XPG, and PCNA.
- His-p53 and FLAG-XPG significantly stimulated NTH1's Tg DNA glycosylase/AP lyase activity.
- PCNA did not show a stimulatory effect on NTH1 activity.
Conclusions:
- NTH1 interacts directly with p53, XPG, and PCNA.
- p53 and XPG positively regulate NTH1's DNA repair function.
- These findings suggest a regulatory mechanism for base excision repair of thymine glycol.
- A potential connection between BER and other cellular pathways is indicated.