PU.1, Interferon Regulatory Factor (IRF) 2, and the Interferon Consensus Sequence-binding Protein (ICSBP/IRF8) cooperate to activate NF1 transcription in differentiating myeloid cells

Weiqi Huang, Elizabeth Horvath, Elizabeth A. Eklund*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

Nf1 (neurofibromin 1) is a Ras-GAP protein that regulates cytokine-induced proliferation of myeloid cells. In previous studies, we found that the interferon consensus sequence-binding protein (ICSBP; also referred to as interferon regulatory factor 8) activates transcription of the gene encoding Nf1 (the NF1 gene) in differentiating myeloid cells. We also found that NF1 activation requires cytokine-stimulated phosphorylation of a conserved tyrosine residue in the interferon regulatory factor (IRF) domain of ICSBP/IRF8. In this study, we found that ICSBP/IRF8 cooperates with PU.1 and interferon regulatory factor 2 to activate a composite ets/IRF-cis element in the NF1 promoter. We found that PU.1 binds directly to the NF1-cis element, and DNA-bound PU.1 interacts with IRF2, recruiting IRF2 to the cis element. This interaction requires cytokine-induced phosphorylation of specific serine residues in the PU.1 PEST domain and of a conserved tyrosine residue in the IRF domain of IRF2. We found that ICSBP/IRF8 interaction with the NF1-cis element requires pre-binding of PU.1 and IRF2. The conserved IRF domain tyrosine in ICSBP/IRF8 is required for interaction with the DNA-bound PU.1-IRF2 heterodimer. NF1 deficiency in myeloid progenitor cells results in cytokine hypersensitivity and myeloproliferation. Therefore, these studies identify a target gene for the previously observed tumor-suppressor effect of PU.1. Additionally, these studies identify a tumor-suppressor function for the "oncogenic" transcription factor, IRF2.

Original languageEnglish (US)
Pages (from-to)6629-6643
Number of pages15
JournalJournal of Biological Chemistry
Volume282
Issue number9
DOIs
StatePublished - Mar 2 2007

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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