Previous Article | Next Article 
Molecular and Cellular Biology, September 2004, p. 7987-7997, Vol. 24, No. 18
0270-7306/04/$08.00+0 DOI: 10.1128/MCB.24.18.7987-7997.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.
Regulation of Human p53 Activity and Cell Localization by Alternative Splicing
Anirban Ghosh,
Deborah Stewart,
and Greg Matlashewski*
Department of Microbiology and Immunology, McGill University, Montreal, Canada
Received 6 May 2004/
Accepted 14 June 2004
The development of cancer is a multistep process involving mutations in proto-oncogenes, tumor suppressor genes, and other genes which control cell proliferation, telomere stability, angiogenesis, and other complex traits. Despite this complexity, the cellular pathways controlled by the p53 tumor suppressor protein are compromised in most, if not all, cancers. In normal cells, p53 controls cell proliferation, senescence, and/or mediates apoptosis in response to stress, cell damage, or ectopic oncogene expression, properties which make p53 the prototype tumor suppressor gene. Defining the mechanisms of regulation of p53 activity in normal and tumor cells has therefore been a major priority in cell biology and cancer research. The present study reveals a novel and potent mechanism of p53 regulation originating through alternative splicing of the human p53 gene resulting in the expression of a novel p53 mRNA. This novel p53 mRNA encodes an N-terminally deleted isoform of p53 termed p47. As demonstrated within, p47 was able to effectively suppress p53-mediated transcriptional activity and impair p53-mediated growth suppression. It was possible to select for p53-null cells expressing p47 alone or coexpressing p53 in the presence of p47 but not cells expressing p53 alone. This showed that p47 itself does not suppress cell viability but could control p53-mediated growth suppression. Interestingly, p47 was monoubiquitinated in an Mdm2-independent manner, and this was associated with its export out of the nucleus. In the presence of p47, there was a reduction in Mdm2-mediated polyubiquitination and degradation of p53, and this was also associated with increased monoubiquitination and nuclear export of p53. The expression of p47 through alternative splicing of the p53 gene thus has a major influence over p53 activity at least in part through controlling p53 ubiquitination and cell localization.
* Corresponding author. Mailing address: Department of Microbiology and Immunology, McGill University, 3775 University St., Room 511, Montreal, Quebec, Canada H3A 2B4. Phone: (514) 398-3914. Fax: (514) 398-7052. E-mail:
greg.matlashewski{at}mcgill.ca.
A.G. and D.S. contributed equally to this research.
Molecular and Cellular Biology, September 2004, p. 7987-7997, Vol. 24, No. 18
0022-538X/04/$08.00+0 DOI: 10.1128/MCB.24.18.7987-7997.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.
This article has been cited by other articles:
-
Lefkimmiatis, K., Caratozzolo, M. F., Merlo, P., D'Erchia, A. M., Navarro, B., Levrero, M., Sbisa', E., Tullo, A.
(2009). p73 and p63 Sustain Cellular Growth by Transcriptional Activation of Cell Cycle Progression Genes. Cancer Res.
69: 8563-8571
[Abstract]
[Full Text]
-
Ghosh, A., Kuppusamy, H., Pilarski, L. M.
(2009). Aberrant Splice Variants of HAS1 (Hyaluronan Synthase 1) Multimerize with and Modulate Normally Spliced HAS1 Protein: A POTENTIAL MECHANISM PROMOTING HUMAN CANCER. J. Biol. Chem.
284: 18840-18850
[Abstract]
[Full Text]
-
Rosenbluth, J. M., Pietenpol, J. A.
(2008). The jury is in: p73 is a tumor suppressor after all. Genes Dev.
22: 2591-2595
[Abstract]
[Full Text]
-
Avery-Kiejda, K. A., Zhang, X. D., Adams, L. J., Scott, R. J., Vojtesek, B., Lane, D. P., Hersey, P.
(2008). Small Molecular Weight Variants of p53 Are Expressed in Human Melanoma Cells and Are Induced by the DNA-Damaging Agent Cisplatin. Clin. Cancer Res.
14: 1659-1668
[Abstract]
[Full Text]
-
Malaguarnera, R., Vella, V., Pandini, G., Sanfilippo, M., Pezzino, V., Vigneri, R., Frasca, F.
(2008). TAp73{alpha} Increases p53 Tumor Suppressor Activity in Thyroid Cancer Cells via the Inhibition of Mdm2-Mediated Degradation. Mol Cancer Res
6: 64-77
[Abstract]
[Full Text]
-
Chan, W. M., Poon, R. Y.C.
(2007). The p53 Isoform {Delta}p53 Lacks Intrinsic Transcriptional Activity and Reveals the Critical Role of Nuclear Import in Dominant-Negative Activity. Cancer Res.
67: 1959-1969
[Abstract]
[Full Text]
-
Valbuena, A., Vega, F. M., Blanco, S., Lazo, P. A.
(2006). p53 Downregulates Its Activating Vaccinia-Related Kinase 1, Forming a New Autoregulatory Loop.. Mol. Cell. Biol.
26: 4782-4793
[Abstract]
[Full Text]
-
Anensen, N., Oyan, A. M., Bourdon, J.-C., Kalland, K. H., Bruserud, O., Gjertsen, B. T.
(2006). A Distinct p53 Protein Isoform Signature Reflects the Onset of Induction Chemotherapy for Acute Myeloid Leukemia.. Clin. Cancer Res.
12: 3985-3992
[Abstract]
[Full Text]
-
Frasca, F., Rustighi, A., Malaguarnera, R., Altamura, S., Vigneri, P., Del Sal, G., Giancotti, V., Pezzino, V., Vigneri, R., Manfioletti, G.
(2006). HMGA1 Inhibits the Function of p53 Family Members in Thyroid Cancer Cells.. Cancer Res.
66: 2980-2989
[Abstract]
[Full Text]
-
Delettre, C., Yuste, V. J., Moubarak, R. S., Bras, M., Lesbordes-Brion, J.-C., Petres, S., Bellalou, J., Susin, S. A.
(2006). AIFsh, a Novel Apoptosis-inducing Factor (AIF) Pro-apoptotic Isoform with Potential Pathological Relevance in Human Cancer. J. Biol. Chem.
281: 6413-6427
[Abstract]
[Full Text]
-
Mills, A. A.
(2005). p53: link to the past, bridge to the future. Genes Dev.
19: 2091-2099
[Full Text]
-
Bourdon, J.-C., Fernandes, K., Murray-Zmijewski, F., Liu, G., Diot, A., Xirodimas, D. P., Saville, M. K., Lane, D. P.
(2005). p53 isoforms can regulate p53 transcriptional activity. Genes Dev.
19: 2122-2137
[Abstract]
[Full Text]
-
Stewart, D., Ghosh, A., Matlashewski, G.
(2005). Involvement of Nuclear Export in Human Papillomavirus Type 18 E6-Mediated Ubiquitination and Degradation of p53. J. Virol.
79: 8773-8783
[Abstract]
[Full Text]
-
Harms, K. L., Chen, X.
(2005). The C Terminus of p53 Family Proteins Is a Cell Fate Determinant. Mol. Cell. Biol.
25: 2014-2030
[Abstract]
[Full Text]