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Status epilepticus induces p53 sequence-specific DNA binding in mature rat brain
1Program in Neurobiology, University of Southern California, Los Angeles, CA 90089-2520, USA.
Brain Research. Molecular Brain Research
|January 8, 1999
Summary
The tumor suppressor protein p53 becomes active in the brain after seizures. This suggests p53 acts as a transcription factor, potentially regulating genes involved in excitotoxic neuronal apoptosis.
Area of Science:
- Neuroscience
- Molecular Biology
- Genetics
Background:
- The tumor suppressor gene p53 is implicated in neuronal apoptosis following excitotoxin exposure.
- Excitotoxic cell death is a significant concern in neurological disorders.
Purpose of the Study:
- To investigate if the p53 protein functions as a transcription factor during excitotoxic neuronal death.
- To measure p53's DNA-binding activity after kainic acid-induced seizures.
Main Methods:
- Electrophoretic mobility shift assays (EMSA) were employed to assess p53's sequence-specific DNA-binding activity.
- Kainic acid (KA) was used to induce seizures in a model of excitotoxicity.
- Experiments included pre-treatment with cycloheximide (protein synthesis inhibitor) and a p53 monoclonal antibody (PAb421).
Main Results:
- A rapid and significant increase in p53 DNA-binding activity was observed in kainate-vulnerable brain regions 2.5 hours post-seizure.
- This elevated activity persisted for up to 16 hours, returning to baseline by 30 hours after KA injection.
- Inhibition of protein synthesis and p53 antibody pre-incubation significantly reduced KA-induced p53 DNA-binding activity.
Conclusions:
- These findings indicate that p53 protein likely functions as a transcription factor in the context of KA-induced excitotoxicity.
- Activated p53 may regulate the expression of downstream genes critical for neuronal apoptosis.
- This study provides evidence for p53's role in the molecular mechanisms of excitotoxic neuronal death.