G-CSF receptor-mediated up-regulation of c-fos but not c-raf mRNA expression in myeloid cells.
Granulocyte colony stimulating factor (G-CSF) regulates survival, proliferation, and differentiation of myeloid precursor cells. One of the signaling mechanisms for the G-CSF receptor (G-CSF-R) involves the activation of Ras/MAP kinase (MEK) pathway. Since Raf is an important, common link between Ras and MEK in the Ras-Raf-MEK cascade, we studied the expression of c-raf mRNA in G-CSF-treated myeloid precursor cell lines--NFS-60 and HL-60. G-CSF did not alter c-raf mRNA expression in these cells up to 24 h, but induced a transient up-regulation of c-fos mRNA expression between 15-60 min post-treatment. Our results show that G-CSF triggers a de novo induction of c-fos but not c-raf mRNA, and suggests that G-CSF-R-mediated activation of Ras/MEK pathway may involve post-transcriptional mechanisms of Raf regulation.
Deshpande
R V
RV
James Ewing Laboratory of Developmental Hematopoiesis, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Moore
M A
MA
D001854:Bone Marrow Cells / Q000502:physiology*; D002455:Cell Division; D018922:HL-60 Cells; D006801:Humans; D016133:Polymerase Chain Reaction; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics*; D019908:Proto-Oncogene Proteins c-raf / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis*; D016188:Receptors, Granulocyte Colony-Stimulating Factor / Q000502:physiology*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D016188:Receptors, Granulocyte Colony-Stimulating Factor; D019908:Proto-Oncogene Proteins c-raf