The Cellular Response to Induction of the p21 c-Ha-ras Oncoprotein Includes Stimulation of Jun Gene Expression

EMBO J. 1989 Mar;8(3):815-22.

Abstract

We have studied the effects of c-Ha-ras oncogene in mouse NIH 3T3 fibroblasts by DNA transfection and analysis of gene expression at the mRNA and protein level in a heat- and heavy metal-inducible model system. The human c-Ha-ras proto-oncogene and oncogene were cloned under the hsp70 heat-shock promoter. Clonal lines of cells with negligible basal expression of the hsp-c-Ha-ras oncogene construct were chosen on the basis of the inducibility of p21c-Ha-ras protein and several transformation parameters. We demonstrate that the expression of ornithine decarboxylase (ODC) mRNA is enhanced approximately 4-6 h after the induction of the p21c-Ha-ras oncoprotein. This increase was reversible upon cessation of c-Ha-ras mRNA and protein synthesis, while constitutively elevated ODC was characteristic for stably c-Ha-ras-transformed cells. The high-level expression of ODC in ras-transformed cells was insensitive to tumour promoter stimulation. A similar mRNA induction by c-Ha-rasVal-12 was also observed for two other serum- and tumour promoter-regulated genes associated with the transformed phenotype: transin (stromelysin) and the glucose transporter. This prompted us to examine also potential changes in the expression of the serum- and tumour promoter-induced transcription factor genes junB and c-jun after induction of the hsp--c-Ha-ras construct. The junB mRNA was enhanced approximately 10-fold and the c-jun oncogene mRNA to a lesser degree in the hsp--c-Ha-ras-transfected cells after zinc activation of the hsp70 promoter. These effects were not seen in similarly treated control cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line, Transformed
  • Cloning, Molecular
  • DNA-Binding Proteins / biosynthesis
  • DNA-Binding Proteins / genetics*
  • Gene Expression Regulation
  • Heat-Shock Proteins / genetics
  • Humans
  • Matrix Metalloproteinase 3
  • Metalloendopeptidases / genetics
  • Mice
  • Monosaccharide Transport Proteins / genetics
  • Ornithine Decarboxylase / genetics
  • Proto-Oncogene Proteins / biosynthesis
  • Proto-Oncogene Proteins / genetics*
  • Proto-Oncogene Proteins c-jun
  • Proto-Oncogene Proteins p21(ras)
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Tetradecanoylphorbol Acetate / pharmacology
  • Transcription Factors / biosynthesis
  • Transcription Factors / genetics*

Substances

  • DNA-Binding Proteins
  • Heat-Shock Proteins
  • Monosaccharide Transport Proteins
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-jun
  • RNA, Messenger
  • Transcription Factors
  • Metalloendopeptidases
  • Matrix Metalloproteinase 3
  • HRAS protein, human
  • Proto-Oncogene Proteins p21(ras)
  • Ornithine Decarboxylase
  • Tetradecanoylphorbol Acetate