Regulated expression systems are invaluable for studying gene function and offer advantages of dosage dependent and temporally defined gene expression, and limits possible clonal variation when toxic or pleiotropic genes are over-expressed. Previously, establishment of inducible expression systems, such as tetracycline and ecdysone inducible systems, required assessment of the inducible characteristics of individual clones by tedious luciferase assays. Taking advantage of a GFP reporter controlled by tetracycline or ecdysone responsive element and fluorescence activated cell sorting (FACS), we propose a simple and efficient strategy to select highly inducible cell lines according to their fluorescence profiles after transiently transfecting the candidate cell pools with a surrogate GFP reporter. We demonstrate tetracycline and ecdysone inducible systems could be set up in Madin Darby canine kidney (MDCK) and Human Embryonic Kidney 293 (HEK293) cells employing this selection scheme. Importantly, this dual regulatory expression system is applied in studying the complex interplay between two Ras related small GTPases, Cdc42 and Rac1, on detachment induced apoptosis. Furthermore, establishment of two tightly regulated expression systems in one target cell line could be of great advantage for dissecting small GTPase Rac1 transduced signalling pathways by global gene expression approaches such as proteomic assays.