The protooncogene c-myb increases the expression of insulin-like growth factor 1 and insulin-like growth factor 1 receptor messenger RNAs by a transcriptional mechanism

Cancer Res. 1991 Nov 1;51(21):5997-6000.


The protooncogene c-myb is the cellular equivalent of the viral transforming oncogene v-myb. When human c-myb is constitutively expressed in Balb/c3T3 cells it abrogates their absolute requirement for insulin-like growth factor 1 (IGF-1). We show now, in two different cell lines, that the constitutive expression of the protooncogene c-myb causes an increase in both IGF-1 and IGF = 1 receptor mRNA levels. This increase in mRNA levels is due, at least in part, to an increase in the rate of transcription since, by run-on assay, cells carrying the human c-myb cDNA show a 3-fold increase in transcriptional rates in comparison to the control parent cell lines. The increased expression of IGF-1 receptor mRNA also results in an increased number of IGF-1 binding sites per cell. Although some oncogenes have been described that are homologous to growth factors, or growth factor receptors, c-myb seems to represent a novel way of oncogene action inasmuch as it increases the expression of both a growth factor receptor and its ligand, thus establishing a quasi-autocrine mechanism which modifies the growth factor requirements of the cell and its growth regulation.

Publication types

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

MeSH terms

  • 3T3 Cells
  • Animals
  • Base Sequence
  • Cell Line
  • Cricetinae
  • DNA Probes
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Insulin-Like Growth Factor I / genetics*
  • Mesocricetus
  • Mice
  • Molecular Sequence Data
  • Oligodeoxyribonucleotides
  • Oncogenes*
  • Plasmids
  • Polymerase Chain Reaction
  • Proto-Oncogenes*
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism
  • Receptors, Cell Surface / genetics*
  • Receptors, Somatomedin
  • Restriction Mapping
  • Thymidine Kinase / genetics
  • Transcription, Genetic*
  • Transfection*


  • DNA Probes
  • Oligodeoxyribonucleotides
  • RNA, Messenger
  • Receptors, Cell Surface
  • Receptors, Somatomedin
  • Insulin-Like Growth Factor I
  • Thymidine Kinase