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Tumor spectrum analysis in p53-mutant mice
T Jacks1, L Remington, B O Williams
1Center for Cancer Research, Massachusetts Institute of Technology, Cambridge 02139.
Background:
The p53 tumor suppressor gene is mutated in a large percentage of human malignancies, including tumors of the colon, breast, lung and brain. Individuals who inherit one mutant allele of p53 are susceptible to a wide range of tumor types. The gene encodes a transcriptional regulator that may function in the cellular response to DNA damage. The construction of mouse strains carrying germline mutations of p53 facilitates analysis of the function of p53 in normal cells and tumorigenesis.
Results:
In order to study the effects of p53 mutation in vivo, we have constructed a mouse strain carrying a germline disruption of the gene. This mutation removes approximately 40% of the coding capacity of p53 and completely eliminates synthesis of p53 protein. As observed previously for a different germline mutation of p53, animals homozygous for this p53 deletion mutation are viable but highly predisposed to malignancy. Heterozygous animals also have an increased cancer risk, although the distribution of tumor types in these animals differs from that in homozygous mutants. In most cases, tumorigenesis in heterozygous animals is accompanied by loss of the wild-type p53 allele.
Conclusion:
We reaffirm that p53 function is not required for normal mouse development and conclude that p53 status can strongly influence tumor latency and tissue distribution.
Insights
The p53 tumor suppressor gene is crucial for preventing cancer. Disrupting p53 in mice leads to increased cancer predisposition and altered tumor development, highlighting its role in tumorigenesis.
Area of Science:
- Molecular Biology
- Genetics
- Oncology
Background:
- The p53 tumor suppressor gene is frequently mutated in human cancers.
- Inherited p53 mutations increase susceptibility to various tumor types.
- p53 is a transcriptional regulator involved in DNA damage response.
Purpose of the Study:
- To investigate the in vivo effects of p53 gene disruption.
- To analyze the role of p53 in normal cellular function and cancer development.
- To create and study a mouse model with a germline p53 deletion.
Main Methods:
- Construction of a mouse strain with a germline p53 deletion mutation.
- Analysis of p53 protein synthesis elimination.
- Phenotypic characterization of homozygous and heterozygous mutant mice.
Main Results:
- Mice with homozygous p53 deletion are viable but highly prone to malignancy.
- Heterozygous mice also exhibit increased cancer risk with distinct tumor types.
- Tumorigenesis in heterozygous mice often involves loss of the wild-type p53 allele.
Conclusions:
- p53 function is not essential for normal mouse development.
- p53 status significantly impacts tumor latency and tissue distribution.
- This study reaffirms the critical role of p53 in tumor suppression.