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Regulation of mutant p53 temperature-sensitive DNA binding
P Friedlander1, Y Legros, T Soussi
1Department of Biological Sciences, Columbia University, New York, New York 10027, USA.
The Journal of Biological Chemistry
|October 11, 1996
Summary
Mutant tumor suppressor p53 proteins can bind DNA at lower temperatures, but lose this ability when heated. Specific antibodies targeting an N-terminal epitope can restore DNA binding at physiological temperatures.
Area of Science:
- Molecular Biology
- Cancer Research
- Protein Biochemistry
Background:
- Mutations in the tumor suppressor gene p53 are common in human cancers.
- Understanding the DNA binding properties of mutant p53 is crucial for cancer therapy.
Purpose of the Study:
- To investigate the DNA binding capabilities of various tumor-derived mutant p53 proteins.
- To explore methods for restoring the DNA binding function of mutant p53.
Main Methods:
- Immunopurification of tumor-derived mutant p53 proteins.
- Assessment of DNA binding at different temperatures (25-37°C).
- Analysis of transcriptional activation in transfected cells.
- Evaluation of antibody stabilization of mutant p53 DNA binding.
Main Results:
- Mutant p53 proteins exhibited defective DNA binding at 37°C but bound specifically at lower temperatures (25-33°C).
- Heating mutant p53 irreversibly abolished DNA binding at lower temperatures.
- Monoclonal antibodies recognizing an N-terminal epitope (amino acids 46-55) significantly stabilized mutant p53 binding at 37°C.
- Antibody fragments also restored DNA binding, unlike antibodies targeting other epitopes.
Conclusions:
- Major hot-spot p53 mutants retain the intrinsic ability to bind DNA.
- An N-terminal region of p53 is critical for maintaining DNA binding at physiological temperatures.
- Developing small molecules to stabilize mutant p53 at physiological temperatures is a potential therapeutic strategy.