Growth-promoting cytokines induce expression of nuclear proto-oncogenes that play critical roles in the regulation of cell proliferation. c-myc gene is one of those nuclear proto-oncogenes, whose regulation mechanisms of cytokine-mediated expression are not fully understood. Here, I generated a green fluorescent protein (GFP) reporter system that faithfully reflects interleukin-3 (IL-3)-induced c-myc gene expression. Flowcytometric analysis revealed cytokine-specific expression of reporter GFP. Kinetics of GFP mRNA expression was similar to that of endogenous c-myc mRNA. The reporter cell line will be a useful tool for studies of cell proliferation regulation through analysis of cytokine-induced c-myc gene expression. (C) 2009, The Society for Biotechnology, Japan. All rights reserved.