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Complex of simian virus large T antigen and p53 can bind DNA specifically
1Department of Biochemistry, College of Medicine, National Cheng Kung University, Tainan, Taiwan, R.O.C.
Abstract:
The DNA-binding activity of p53 was suggested to be abrogated by binding of large T antigen. However we demonstrate that a fraction of p53 can form a complex with large T antigen and still bind DNA specifically. In EMSA analysis, both PAb 416 and 419 anti-large-T antibodies could induce supershift on p53-DNA complex using extracts derived from two T-antigen-transformed cell lines. In EMSA-Western analysis, one of the p53-complexes was shown to contain large T antigen.
Insights
Large T antigen does not fully inhibit p53 DNA binding. A portion of p53 forms a complex with large T antigen but retains specific DNA-binding activity, confirmed by supershift assays.
Area of Science:
- Molecular Biology
- Virology
- Cancer Research
Background:
- The tumor suppressor protein p53 plays a crucial role in maintaining genomic stability.
- Large T antigen (LT) from simian virus 40 (SV40) is known to interact with p53.
- Previous studies suggested LT binding abrogates p53's DNA-binding activity.
Purpose of the Study:
- To investigate the effect of large T antigen binding on p53's DNA-binding capacity.
- To determine if p53 can retain DNA-binding activity while complexed with large T antigen.
Main Methods:
- Electrophoretic Mobility Shift Assay (EMSA) was employed to analyze p53-DNA complexes.
- Specific anti-large-T antibodies (PAb 416 and 419) were used for supershift analysis.
- EMSA-Western blotting confirmed the presence of large T antigen within p53 complexes.
Main Results:
- A fraction of p53 forms a complex with large T antigen.
- This p53-large T antigen complex retains the ability to bind DNA specifically.
- Supershift analysis using anti-large-T antibodies confirmed the presence of large T antigen in p53-DNA complexes from T-antigen-transformed cell lines.
Conclusions:
- Large T antigen does not completely abolish the DNA-binding activity of p53.
- A subset of p53 remains functionally active in DNA binding even when associated with large T antigen.
- These findings refine the understanding of p53-large T antigen interactions in viral oncogenesis.