The product of a novel growth factor activated gene, fos B, interacts with JUN proteins enhancing their DNA binding activity

EMBO J. 1989 Mar;8(3):805-13.


We have identified a gene, fos B, encoding a nuclear protein of 338 amino acids presenting a 70% homology with c-fos, whose expression is activated during G0/G1 transition. Growth factor stimulation of quiescent cells leads to a rapid and transient accumulation of fos B mRNA, with kinetics similar to those of c-fos. The induction of fos B mRNA levels is in part due to a dramatic increase in the transcription of the gene. The half-life of fos B mRNA is in the order of 10-15 min. Both transcriptional activation and mRNA stability are substantially increased in the presence of protein synthesis inhibitors. Immunoprecipitation studies showed that fos B as c-fos protein, forms a complex in vitro with c-jun and jun B proteins in the absence of a target binding sequence. Gel retardation assays demonstrated that fos B protein positively influences the binding of c-jun and jun B proteins to an AP-1 binding consensus sequence, suggesting that fos B protein plays a role in control of gene expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Binding Sites
  • DNA / genetics
  • DNA-Binding Proteins / metabolism*
  • Gene Expression Regulation
  • Mice
  • Molecular Sequence Data
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-fos
  • Proto-Oncogene Proteins c-jun
  • Proto-Oncogenes
  • Sequence Homology, Nucleic Acid
  • Transcription Factors / metabolism*


  • DNA-Binding Proteins
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-fos
  • Proto-Oncogene Proteins c-jun
  • Transcription Factors
  • DNA

Associated data

  • GENBANK/X14897