Transforming activity of EWS/FLI is not strictly dependent upon DNA-binding activity

Oncogene. 1999 Sep 30;18(40):5592-7. doi: 10.1038/sj.onc.1202940.


In approximately 85% of Ewing sarcomas, chromosomal translocations give rise to the chimeric gene EWS/FLI, encoding the N-terminus of the RNA binding protein EWS fused to the DNA-binding domain of the ETS protein FLI-1. EWS/FLI is a stronger transcriptional activator than wild-type FLI-1, although both proteins bind to the same DNA sequences in vitro. In addition, EWS/FLI, but not FLI-1, is a transforming oncogene in NIH3T3 fibroblasts. EWS/FLI is thought to transform through its ability to deregulate the expression of target genes. We introduced several point mutations into the ETS domain of EWS/FLI that abolished DNA-binding activity. Although two of these mutations disrupted the transforming activity of EWS/FLI, one mutated protein containing a substitution of isoleucine 347 with glutamic acid (I347E) retained diminished transforming activity. In addition, EWS/FLI I347E did not activate expression of the endogenous EWS/FLI target gene manic fringe (MFNG). These studies demonstrate that a portion of the oncogenic activity of EWS/FLI is independent of FLI DNA-binding activity.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3T3 Cells
  • Amino Acid Substitution
  • Animals
  • Bone Neoplasms / genetics*
  • Cell Transformation, Neoplastic / genetics*
  • Consensus Sequence
  • DNA / metabolism*
  • Humans
  • Mice
  • Mutagenesis, Site-Directed
  • Oncogene Proteins, Fusion / metabolism
  • Oncogene Proteins, Fusion / physiology*
  • Point Mutation
  • Proto-Oncogene Protein c-fli-1
  • Proto-Oncogene Proteins / metabolism
  • RNA-Binding Protein EWS
  • Sarcoma, Ewing / genetics*
  • Trans-Activators / metabolism
  • Transcription Factors / metabolism
  • Transcription Factors / physiology*
  • Transcriptional Activation*
  • Tumor Stem Cell Assay


  • EWS-FLI fusion protein
  • Oncogene Proteins, Fusion
  • Proto-Oncogene Protein c-fli-1
  • Proto-Oncogene Proteins
  • RNA-Binding Protein EWS
  • Trans-Activators
  • Transcription Factors
  • proto-oncogene protein Spi-1
  • DNA