Induction of epidermal growth factor receptor gene transcription by transforming growth factor beta 1: association with loss of protein binding to a negative regulatory element

Cell Growth Differ. 1994 Aug;5(8):801-9.

Abstract

Transforming growth factor beta (TGF-beta) is a potent modulator of cell growth in many systems. In normal rat kidney fibroblasts, TGF-beta 1 increases epidermal growth factor (EGF) receptor gene transcription and synergizes with EGF to stimulate growth in soft agar, a characteristic of the transformed phenotype. In order to identify the target of TGF-beta 1 action, we have used a series of 5' deletion mutants of the EGF receptor promoter linked to a chloramphenicol acetyltransferase reporter gene (ERCAT). The TGF-beta response element(s) was localized to a cis-regulatory region which resides between positions -919 and -860 relative to the ATG translation initiation codon of the EGF receptor promoter. This 60-base pair region contains a repressor of the EGF receptor promoter and a TGF-beta inhibitory element that mediates TGF-beta 1 suppression of transin/stromelysin gene transcription through binding of a Fos-containing protein complex. Cotransfection of c-fos, c-jun, or both expression vectors with the intact or 5'-deleted ERCAT constructs identified several Fos-responsive inhibitory regions within the EGF receptor promoter, but these did not localize to the -919 to -860 promoter region. Mobility shift assays showed binding of the 60-base pair DNA fragment to proteins in extracts from untreated normal rat kidney cells; the binding was specifically competed by oligonucleotides containing a CAGATG sequence but not by oligonucleotides containing the EGF receptor repressor or the TGF-beta inhibitory element. TGF-beta 1 treatment but not anti-Fos antibody caused a decrease in specific 60-base pair DNA-protein complex formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

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

MeSH terms

  • Animals
  • Base Sequence
  • Cell Line
  • ErbB Receptors / genetics*
  • Genes, Regulator / drug effects*
  • Humans
  • Molecular Sequence Data
  • Mutation
  • Promoter Regions, Genetic*
  • Protein Binding
  • Proto-Oncogene Proteins c-fos / physiology
  • Rats
  • Transcription, Genetic / drug effects*
  • Transcriptional Activation
  • Transfection
  • Transforming Growth Factor beta / pharmacology*

Substances

  • Proto-Oncogene Proteins c-fos
  • Transforming Growth Factor beta
  • ErbB Receptors