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Human p53 inhibits growth in Schizosaccharomyces pombe
J R Bischoff1, D Casso, D Beach
1Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, New York 11724.
Abstract:
Overexpression of wild-type p53 in mammalian cells blocks growth. We show here that the overexpression of wild-type human p53 in the fission yeast Schizosaccharomyces pombe also blocks growth, whereas the overexpression of mutant forms of p53 does not. The p53 polypeptide is located in the nucleus and is phosphorylated at both the cdc2 site and the casein kinase II site in S. pombe. A new dominant mutation of p53, resulting in the change of a cysteine to an arginine at amino acid residue 141, was identified. The results presented here demonstrate that S. pombe could provide a simple system for studying the mechanism of action of human p53.
Insights
Overexpression of wild-type human p53 protein inhibits growth in yeast, similar to mammalian cells. Mutant p53 forms do not block growth, suggesting yeast as a model for p53 research.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Wild-type p53 protein is known to inhibit cell growth in mammalian systems.
- Understanding p53's function is crucial due to its role in cancer.
Purpose of the Study:
- To investigate the effects of human p53 overexpression in the fission yeast Schizosaccharomyces pombe.
- To determine if S. pombe can serve as a model system for studying p53.
Main Methods:
- Overexpression of wild-type and mutant human p53 in S. pombe.
- Localization studies of p53 within yeast cells.
- Identification of p53 mutations and phosphorylation sites.
Main Results:
- Overexpression of wild-type p53 blocked S. pombe growth, mirroring mammalian cell responses.
- Overexpression of mutant p53 forms did not inhibit growth.
- Human p53 was found to be localized in the nucleus and phosphorylated at specific sites (cdc2 and casein kinase II) in S. pombe.
- A novel dominant p53 mutation (Cys141Arg) was identified.
Conclusions:
- Schizosaccharomyces pombe is a suitable and simple model for studying human p53's mechanism of action.
- The growth-inhibitory function of p53 is conserved between yeast and mammalian cells.
- Phosphorylation and specific mutations affect p53 activity in vivo.