Abstract
We have studied the mechanism of mutant p53-mediated oncogenesis using several tumor-derived mutants. Using a colony formation assay, we found that the majority of the mutants increased the number of colonies formed compared to the vector. Expression of tumor-derived p53 mutants increases the rate of cell growth, suggesting that the p53 mutants have 'gain of function' properties. We have studied the gene expression profile of cells expressing tumor-derived p53-D281G to identify genes transactivated by mutant p53. We report the transactivation of two genes, asparagine synthetase and human telomerase reverse transcriptase. Quantitative real-time PCR confirms this upregulation. Transient transfection promoter assays verify that tumor-derived p53 mutants transactivate these promoters significantly. An electrophoretic mobility shift assay shows that tumor-derived p53-mutants cannot bind to the wild-type p53 consensus sequence. The results presented here provide some evidence of a possible mechanism for mutant p53-mediated transactivation.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Substitution
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Aspartate-Ammonia Ligase / biosynthesis
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Aspartate-Ammonia Ligase / genetics
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Cell Division
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Cell Line, Tumor
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Cell Transformation, Neoplastic / genetics*
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Consensus Sequence
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DNA-Binding Proteins / metabolism
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Gene Expression Profiling
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Gene Expression Regulation, Neoplastic
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Genes, Tumor Suppressor
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Genes, p53*
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Humans
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Mutation, Missense
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Neoplasms / genetics*
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Nuclear Proteins / metabolism
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Point Mutation
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Promoter Regions, Genetic / genetics
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Protein Binding
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Protein Structure, Tertiary
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Recombinant Fusion Proteins / physiology
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Structure-Activity Relationship
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Telomerase / biosynthesis
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Telomerase / genetics
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Transcriptional Activation / genetics*
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Tumor Protein p73
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Tumor Stem Cell Assay
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Tumor Suppressor Protein p53 / chemistry
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Tumor Suppressor Protein p53 / physiology*
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Tumor Suppressor Proteins
Substances
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DNA-Binding Proteins
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Nuclear Proteins
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Recombinant Fusion Proteins
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Tumor Protein p73
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Tumor Suppressor Protein p53
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Tumor Suppressor Proteins
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Telomerase
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Aspartate-Ammonia Ligase