Leukotriene C-4 synthase is a key enzyme in leukotriene biosynthesis. Its gene has been cloned and mapped to mouse chromosome 11. Expression occurs in cells of myeloid origin and also in the choroid plexus, the hypothalamus and the medial eminence of mouse brain. In this study a vector that expresses enhanced green fluorescent protein (eGFP) under the control of the mouse leukotriene C-4 synthase promoter was constructed and used to study promoter activity in different cell lines. Specific eGFP expression was observed in human monocytic leukemia (THP-1) and rat basophilic leukemia (RBL-1) myeloid cells which both express leukotriene C-4 synthase, but not in human embryonic kidney (HEK293/T) epithelial cells which do not express this enzyme. In the myeloid cells, but not in the epithelial cells, we observed that the leukotriene C-4 synthase promoter activity was stimulated by 12-O-tetradecanoylphorbol-13-acetate and all-trans-retinoic acid. In contrast dimethyl sulfoxide did not affect promoter activity. (C) 2007 Elsevier Inc. All rights reserved.