Establishment of a new cell line for performing sensitive screening of nuclear export inhibitors.

: Cell nuclear import and export of proteins are among the most important processes for cellular homeostasis. Viruses, including influenza virus and HIV-1 also utilize nuclear export machinery for their propagation. Therefore, the specific inhibition of nuclear export can be a good target for the development of antiviral drugs. This report documents the establishment of Madin-Darby Canine Kidney (MDCK) cells stably expressing GFP-NES fusion protein for the sensitive screening of novel nuclear export inhibitors. Leptomycin B (LMB), an inhibitor for the interaction between substrate nuclear export signal (NES) and cellular export factor, CRM1, was used for evaluating the screening system. The low concentration (30 pg/mL) and short time treatment (~10 min) of LMB resulted in the nuclear accumulation of GFP fluorescence.