$Interferon-{\Upsilon}$ and Lipopolysaccaride Induce Mouse Guanylate-Binding Protein 3 (mGBP3) Expression in the Murine Macrophage Cell Line RAW264-7

Mouse guanylate-binding protein 3 (mGBP3) is a 71-kDa GTPase which belongs to GTP-binding protein family. The present study showed that the expression of mGBP3 transcript was readily induced in a dose dependent fashion in the macrophage cell line RAW264.7 treated with either $interferon-{\gamma} (IFN-\gamma)$ or lipopolysaccaride (LPS). The expression of mGBP3 protein was also apparent by 4 and 6 h after the treatment of cells with IFN-\gamma (100 U/ml) or LPS ($1{\mu}g/ml$) , and remained at palteau for at least 24 h. Cycloheximide ($10{\mu}g/ml$) had no effect on the $IFN-\gamma-$ or LPS-induced mGBP3 expression, suggesting that the mGBP3 induction did not require further protein synthesis. Interestingly, a protein kinase C (PKC) inhibitor staurosporine (50 nM) abolished the induction of mGBP3 expression by LPS, but not by $IFN-{\gamma}$. These findings suggest that mGBP3 may be involved in the macrophage activation process and both IFN-\gamma and LS induce the mGBP3 expression through distinct signal transduction pathways.