Current Biology
Volume 4, Issue 1, 1 January 1994, Pages 1-7
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Research Paper
Tumor spectrum analysis in p53-mutant mice

https://doi.org/10.1016/S0960-9822(00)00002-6Get rights and content

Abstract

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.

Section snippets

Background:

The p53 tumor suppressor gene appears to be a critical regulator of normal cell proliferation. This is indicated by the fact that mutant alleles of this gene are found in a majority of human tumors, involving a wide range of tumor types [1]. In addition to the frequent somatic mutation of p53 in sporadic cancer, germline mutation of one allele of this gene in humans causes an inborn predisposition to cancer known as Li-Fraumeni syndrome [2]. Individuals with Li-Fraumeni syndrome are highly

p53 gene targeting

One allele of the p53 gene was disrupted in D3 ES cells using the targeting vector p53KO shown in Figure 1. The neomycin resistance gene (neo) in this vector is flanked by fragments of p53 totaling 8 kilobases (kb); neo replaces approximately 40 % of the p53 coding sequences, beginning within exon 2 (upstream of the initiator codon AUG) and extending into intron 6. The HSV-TK gene follows the p53 sequences to allow negative selection using the protocol of Mansour et al.[18]. p53KO was

Discussion

The method of gene targeting in mouse ES cells [24] has allowed the construction of a large number of novel mouse strains that can be used to study diverse areas of biology, including development, immunology, human genetic disease and cancer. Here, we have described the properties of a mouse strain carrying a targeted deletion mutation in the p53 tumor suppressor gene. Given the importance of p53 mutations in sporadic and familial forms of cancer, this strain and analogous strains constructed

Gene targeting

p53KO was constructed by cloning fragments of the murine p53 gene (isolated from strain BALB/c) [32] into the targeting vector pPNT [33]. The neo gene in p53KO is flanked by a 3.5 kb fragment extending from the Bam HI site in intron 1 to the NcoI in exon 2 and a 5 kb fragment extending from the Bam HI in intron 6 to the Eco RI downstream of exon 11 [32]. Electroporation of p53KO into D3 ES cells [34], subsequent drug selection, and Southern blot analysis were performed as described [28]. The

Acknowledgements

The authors wish to thank P. Hinds, A. Fazeli, P. Mombaerts, K. MacLeod, L. Johnson and S. Lowe for helpful discussion and advice; R. Hynes and J. Rossant for the gift of D3 ES cells; E. Harlow for the gift of antibodies PAb248 and M73; C. Crawford and J. Williams for technical assistance; and M. Weigel for help with preparation of the manuscript. T.J. is a Lucille P. Markey Scholar and this work was funded in part by a grant from the General Cinemas Charitable Trust. R.A.W. is supported in

Tyler Jacks (corresponding author), Lee Remington, Bart O. Williams and Earlene M. Schmitt, Center for Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 USA.

Schlomit Halachmi, Dana-Farber Cancer Institute, 44 Binney Street, Boston, Massachusetts 02215 USA.

Roderick T. Bronson, Department of Pathology, Tufts University Schools of Medicine and Veterinary Medicine, Boston, Massachusetts 02111 USA.

Robert A. Weinberg, Whitehead Institute

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    Tyler Jacks (corresponding author), Lee Remington, Bart O. Williams and Earlene M. Schmitt, Center for Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 USA.

    Schlomit Halachmi, Dana-Farber Cancer Institute, 44 Binney Street, Boston, Massachusetts 02215 USA.

    Roderick T. Bronson, Department of Pathology, Tufts University Schools of Medicine and Veterinary Medicine, Boston, Massachusetts 02111 USA.

    Robert A. Weinberg, Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142 USA.

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