Identification of human p53 mutations with differential effects on the bax and p21 promoters using functional assays in yeast

Oncogene. 1998 Mar 12;16(10):1369-72. doi: 10.1038/sj.onc.1201889.


Recent studies have suggested that a rare class of p53 mutants found in tumours has a subtle transcriptional defect affecting bax induction but not p21 induction. We have therefore developed simple functional assays in yeast which can be used to identify these mutants. Analysis of 51 different mutations observed in human tumours showed that all mutants tested scored as mutant with the bax reporter strain but nine scored as wild-type with the p21 reporter strain. These results, which can be explained by the lower affinity of the p53 protein for the bax site, may suggest that p21 is not the key target of p53 mutations in tumours. Since p21 status has recently been shown to modulate the chemotherapeutic and radiotherapeutic sensitivities of cancerous cells, the functional assays described here may have important clinical implications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cloning, Molecular
  • Consensus Sequence
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins / biosynthesis*
  • Cyclins / genetics
  • Genes, p53*
  • Humans
  • Mutagenesis, Site-Directed
  • Mutation*
  • Neoplasms / genetics
  • Point Mutation
  • Promoter Regions, Genetic*
  • Proto-Oncogene Proteins / biosynthesis*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins c-bcl-2*
  • Recombinant Proteins / biosynthesis
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae / metabolism
  • Transcription, Genetic
  • Tumor Suppressor Protein p53 / biosynthesis*
  • bcl-2-Associated X Protein


  • BAX protein, human
  • CDKN1A protein, human
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Recombinant Proteins
  • Tumor Suppressor Protein p53
  • bcl-2-Associated X Protein