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Identification of an additional negative regulatory region for p53 sequence-specific DNA binding
B F Müller-Tiemann1, T D Halazonetis, J J Elting
1Institute for Bone and Joint Disorders and Cancer, Bayer Corporation, Pharmaceutical Division, 400 Morgan Lane, West Haven, CT 06516, USA. beate.muellertiemann@schering.de
Summary
Researchers identified a new negative regulatory domain in the p53 protein (amino acids 80-93). This domain, along with a known region, cooperatively maintains p53
Area of Science:
- Molecular Biology
- Protein Regulation
- Cancer Research
Background:
- The tumor suppressor protein p53's DNA binding is tightly regulated.
- The C-terminus of p53 is known to inhibit its DNA binding activity in an uninduced state.
- Posttranslational modifications and interacting proteins activate p53 DNA binding, primarily by targeting the C-terminus.
Purpose of the Study:
- To identify the specific interaction sites of p53 with activating peptides.
- To characterize previously unidentified regulatory regions of p53 involved in DNA binding.
Main Methods:
- Peptide affinity precipitation assays using p53 deletion constructs and C-terminal activating peptides.
- DNA binding analyses of p53 deletion constructs.
- In vitro activation of p53 DNA binding using synthetic peptides.
Main Results:
- Two distal regions of p53 (amino acids 80-93 and 364-393) synergistically interact with activating peptides.
- Residues 80-93 were identified as a novel negative regulatory domain of p53, exhibiting similar inhibitory function to residues 364-393.
- Synthetic peptides from the 80-93 region activated p53 sequence-specific DNA binding in vitro.
Conclusions:
- The p53 regions 80-93 and 364-393 cooperatively maintain p53 in a latent, low-affinity DNA binding conformation.
- The newly identified domain (80-93) provides new insights into the regulation of p53 tumor suppressor activity.