Figure 2.

The RSV Gag protein undergoes CRM1-dependent nucleocytoplasmic trafficking. PR domain of the RSV protein was replaced by GFP (green fluorescent protein). Nuclear export of the Gag protein is inhibited by treatment of cells expressing Gag-GFP with leptomycin B (LMB). LMB binds covalently to CRM1 to interfere with Gag transit through the nuclear pore complex (blue barrels) in the nuclear envelope. The Gag-GFP protein localizes primarily to the cytoplasm and at discrete foci along the plasma membrane in untreated quail fibroblasts. Treatment of cells with LMB results in the accumulation of Gag-GFP in the nucleus.