Synergistic activation of the chicken mim-1 gene by v-myb and C/EBP transcription factors

EMBO J. 1993 May;12(5):2027-38.


The retroviral oncogene v-myb encodes a transcriptional activator which is responsible for the activation of the mim-1 gene in myelomonocytic cells transformed by v-myb. The mim-1 promoter contains several myb consensus binding sites and has previously been shown to be regulated directly by v-myb. Here we report that the mim-1 gene is activated synergistically by v-myb and different C/EBP transcription factors. We have cloned a chicken C/EBP-related gene that is highly expressed in myeloid cells and identified it as the chicken homolog of C/EBP beta. A dominant-negative variant of chicken C/EBP beta interferes with the v-myb induced activation of the mim-1 gene in these cells, suggesting that C/EBP beta or another C/EBP transcription factor is required for the activation of mim-1 by v-myb. We found that C/EBP beta and other C/EBP transcription factors confer to fibroblasts the ability to induce the mim-1 gene in the presence of v-myb. Finally we show that, in contrast to v-myb, c-myb synergizes with C/EBP transcription factors only at low concentrations of c-myb protein. Our results suggest a role for C/EBP beta, and possibly for other C/EBP transcription factors, in v-myb function and in myeloid-specific gene activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetyltransferases*
  • Amino Acid Sequence
  • Animals
  • Avian Myeloblastosis Virus
  • Base Sequence
  • CCAAT-Enhancer-Binding Proteins
  • Cell Line
  • Chickens
  • DNA-Binding Proteins / metabolism*
  • Gene Expression Regulation
  • Mice
  • Molecular Sequence Data
  • Muramidase / genetics
  • Nuclear Proteins / metabolism*
  • Oligodeoxyribonucleotides
  • Oncogene Proteins v-myb
  • Promoter Regions, Genetic
  • Proteins / genetics*
  • Proteins / metabolism
  • Rats
  • Retroviridae Proteins, Oncogenic / metabolism*
  • Sequence Homology, Amino Acid
  • Transcription Factors / metabolism*
  • Transcriptional Activation


  • CCAAT-Enhancer-Binding Proteins
  • DNA-Binding Proteins
  • Nuclear Proteins
  • Oligodeoxyribonucleotides
  • Oncogene Proteins v-myb
  • Proteins
  • Retroviridae Proteins, Oncogenic
  • Transcription Factors
  • Acetyltransferases
  • mim-1 protein, Gallus gallus
  • Muramidase

Associated data

  • GENBANK/X70813