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Interaction of p53 with its consensus DNA-binding site
Y Wang1, J F Schwedes, D Parks
1Department of Molecular Genetics and Microbiology, State University of New York, Stony Brook 11794.
Molecular and Cellular Biology
|April 1, 1995
Summary
Murine p53 protein binds DNA cooperatively. A single p53 tetramer recognizes two DNA half-sites, indicating flexibility in its tetramerization domain for specific DNA interactions.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- The p53 protein is a crucial transcription factor involved in cellular responses to stress.
- Understanding the precise mechanism of p53's DNA binding is essential for deciphering its regulatory functions.
Purpose of the Study:
- To analyze the specific interaction of murine p53 with its consensus DNA-binding sequence.
- To elucidate the role of different p53 domains in DNA binding specificity and cooperativity.
Main Methods:
- Used truncated p53 protein segments lacking the C-terminal domain to simplify analysis.
- Investigated DNA binding by p53 amino acids 1-360 (tetramers) and 80-290 (monomers).
- Performed in vivo transcription studies to confirm DNA-protein interactions.
Main Results:
- p53 amino acids 1-360 bind the consensus sequence as tetramers, promoting further tetramer interactions.
- p53 amino acids 80-290 bind as monomers cooperatively, with minimal binding by fewer than four monomers.
- A single p53 tetramer binds the entire consensus DNA site, which comprises two functional half-sites.
- DNA binding is sensitive to alterations within half-sites and the relative orientation of separated half-sites.
Conclusions:
- Wild-type p53 engages consensus DNA sequences as a single tetramer.
- The p53 protein exhibits strong cooperative DNA binding.
- Consensus DNA binding is rotationally specific, and p53 possesses a flexible tetramerization region allowing it to bind separated DNA half-sites.