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Yeast As a Chassis for Developing Functional Assays to Study Human P53
Published on: August 4, 2019
Transcriptional regulation by p53 and p73
M Lokshin1, T Tanaka, C Prives
1Department of Biological Sciences, Columbia University, New York, New York 10027, USA.
Cold Spring Harbor Symposia on Quantitative Biology
|July 28, 2006
Summary
The tumor suppressor p53
Area of Science:
- Molecular Biology
- Cancer Research
- Cell Biology
Background:
- The tumor suppressor p53 regulates gene expression, influencing cell cycle arrest and apoptosis.
- p53 protein levels and modifications are critical for target gene discrimination and cell fate determination.
Purpose of the Study:
- To investigate the role of p53 protein levels in promoter selectivity.
- To compare the functional compensation of p53 by p73 in different cellular contexts.
Main Methods:
- Ectopic expression of p53 in H1299 cells.
- Analysis of p53 target gene activation (p53AIP1, p21WAF1).
- Comparison of exogenous p53 and p73 transcriptional activity.
- Quantification of endogenous p73 and p53 protein levels in HCT116 cells after DNA damage.
Main Results:
- Pro-apoptotic gene p53AIP1 requires higher p53 levels for activation than cell cycle arrest gene p21WAF1.
- Exogenous p73 shows similar activity to p53, but endogenous p73 in HCT116 cells cannot compensate for p53 loss.
- Endogenous TAp73 levels in HCT116 cells are low, even after DNA damage, and remain below basal p53 levels.
Conclusions:
- p53 protein levels significantly influence its promoter selectivity, impacting cell fate outcomes.
- Low endogenous p73 levels, even upon DNA damage, limit its ability to substitute for p53 function.
- These findings suggest that insufficient p73 levels contribute to its inability to act as a major tumor suppressor compared to p53.
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