An autonomous N-terminal transactivation domain in Fos protein plays a crucial role in transformation

EMBO J. 1994 Mar 15;13(6):1467-75.


To date, three functional domains have been defined in c-Fos and v-Fos proteins and have been shown to play a role in transactivation: the leucine zipper mediating hetero-dimerization, the basic DNA contact site, and a C-terminally located transactivation domain (C-TA) harbouring the HOB1 and HOB2 motifs. While the bZip region, consisting of the leucine zipper and the DNA contact site, is indispensable for transformation, the C-TA domain is not required and is actually altered by internal deletions in the FBR-MuSV. We now show that the N-terminal regions of c-Fos and v-Fos contain a second transactivation domain (N-TA). A functionally crucial motif within the N-TA domain, termed NTM, was pinpointed to a approximately 25 amino acid stretch around positions 60-84 which is highly conserved in FosB. Analysis of LexA fusion proteins showed that the N-TA domains of both c-Fos and FosB function in an autonomous fashion in both fibroblasts and yeast. Most importantly, deletion of the NTM motif impairs the transforming properties of v-Fos. Apart from the bZip region, the N-TA domain is the only functional domain required for transformation by v-Fos, at least when its expression is driven by the strong FBR-MuSV-LTR promoter.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Binding Sites
  • Cells, Cultured
  • Conserved Sequence
  • DNA Primers
  • Humans
  • Mice
  • Molecular Sequence Data
  • Mutation
  • Proto-Oncogene Proteins c-fos / genetics
  • Proto-Oncogene Proteins c-fos / metabolism*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Sequence Homology, Amino Acid
  • Transcriptional Activation*
  • Transformation, Genetic*


  • DNA Primers
  • Proto-Oncogene Proteins c-fos