Mitogen regulated induction of FRA-1 proto-oncogene is controlled by the transcription factors binding to both serum and TPA response elements

Oncogene. 2005 Jun 16;24(26):4193-205. doi: 10.1038/sj.onc.1208583.

Abstract

FRA-1, a member of the FOS family of transcription factors, is overexpressed in a variety of human tumors, and contributes to tumor progression. In addition to mitogens, various toxicants and carcinogens persistently induce FRA-1 expression in vitro and in vivo. Although the mitogen induced expression of c-FOS is relatively well understood, it is poorly defined in the case of FRA-1. Our recent analysis of the FRA-1 promoter has shown a critical role for a TRE located at -318 in mediating the TPA-induced expression. The -379 to -283 bp promoter segment containing a critical TRE (-318), however, is insufficient for the induction of FRA-1 promoter. Here, we show that a 40-bp (-276/-237) segment, comprising a TCF binding site and the CArG box (collectively known as serum response element, SRE), and an ATF site, is also necessary for the FRA-1 induction by TPA and EGF. Interestingly, the -283 to +32 bp FRA-1 promoter fragment containing an SRE and an ATF site alone was also insufficient to confer TPA sensitivity to a reporter gene. However, in association with the -318 TRE, the SRE and ATF sites imparted a strong TPA-inducibility to the reporter. Similarly, EGF also required these motifs for the full induction of this gene. Using ChIP assays we show that, in contrast to c-Jun, SRF, Elk1, ATF1 and CREB proteins bind to SRE and ATF sites of the FRA-1 promoter, constitutively. RNAi-mediated knockdown of endogenous SRF, ELK1 and c-JUN protein expression significantly reduced TPA-stimulated FRA-1 promoter activity. Thus, a bipartite enhancer formed by an upstream TRE and the downstream SRE and ATF sites and the cognate factors is necessary and sufficient for the regulation of FRA-1 in response to mitogens.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Activating Transcription Factors
  • Blood Proteins / genetics
  • Blood Proteins / pharmacology
  • Breast Neoplasms / genetics
  • Breast Neoplasms / pathology
  • Disease Progression
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Lung Neoplasms / genetics
  • Lung Neoplasms / pathology
  • Mitogens / pharmacology
  • Promoter Regions, Genetic
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins c-fos / biosynthesis*
  • Proto-Oncogene Proteins c-fos / pharmacology*
  • Serum Response Element
  • Tetradecanoylphorbol Acetate / analogs & derivatives*
  • Tetradecanoylphorbol Acetate / pharmacology*
  • Transcription Factors / genetics
  • Transcription Factors / pharmacology*
  • Tumor Cells, Cultured

Substances

  • Activating Transcription Factors
  • Blood Proteins
  • MAS1 protein, human
  • Mitogens
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins c-fos
  • Transcription Factors
  • fos-related antigen 1
  • 12-O-tetradeca-2,4,6,8-tetranoylphorbol-13-acetate
  • Tetradecanoylphorbol Acetate