Granulocyte colony-stimulating factor induces Egr-1 up-regulation through interaction of serum response element-binding proteins

J Biol Chem. 2000 Jul 21;275(29):22418-26. doi: 10.1074/jbc.M001731200.

Abstract

Granulocyte colony-stimulating factor (G-CSF) stimulates the proliferation and maturation of myeloid progenitor cells both in vitro and in vivo. We showed that G-CSF rapidly and transiently induces expression of egr-1 in the NFS60 myeloid cell line. Transient transfections of NFS60 cells with recombinant constructs containing various deletions of the human egr-1 promoter identified the serum response element (SRE) between nucleotides (nt) -418 and -391 as a critical G-CSF-responsive sequence. The SRE (SRE-1) contains a CArG box, the binding site for the serum response factor (SRF), which is flanked at either side by an ETS protein binding site. We demonstrated that a single copy of the wild-type SRE-1 in the minimal promoter plasmid, pTE2, is sufficient to induce transcriptional activation in response to G-CSF and that both the ETS protein binding site and the CArG box are required for maximal transcriptional activation of the pTE2-SRE-1 construct. In electromobility shift assays using NFS60 nuclear extracts, we identified SRF and the ETS protein Fli-1 as proteins that bind the SRE-1. We also demonstrated through electrophoretic mobility shift assays, using an SRE-1 probe containing a CArG mutation, that Fli-1 binds the SRE-1 independently of SRF. Our data suggest that SRE-binding proteins potentially play a role in G-CSF-induced egr-1 expression in myeloid cells.

Publication types

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

MeSH terms

  • Animals
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Early Growth Response Protein 1
  • Granulocyte Colony-Stimulating Factor / metabolism
  • Granulocyte Colony-Stimulating Factor / pharmacology*
  • Humans
  • Immediate-Early Proteins*
  • Mice
  • Mutation
  • Promoter Regions, Genetic
  • Response Elements / genetics
  • Signal Transduction / drug effects*
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Tumor Cells, Cultured
  • Up-Regulation / drug effects

Substances

  • DNA-Binding Proteins
  • EGR1 protein, human
  • Early Growth Response Protein 1
  • Egr1 protein, mouse
  • Immediate-Early Proteins
  • Transcription Factors
  • Granulocyte Colony-Stimulating Factor