FIG. 1.

Importin α mediates the nuclear import of Vpr without importin β. HeLa cells were permeabilized by treatment with 35 μg/ml digitonin. The cells were incubated with 1 μM GST- and GFP-tagged N17C74 or SV40 NLS in the presence (+) or absence (−) of soluble factors for 20 min at 30°C. After fixation, cells were analyzed by confocal laser scanning microscopy (Radiance 2100; Bio-Rad). Soluble factors were included at the following concentrations: importin α1, 1 μM; importin β, 1 μM; RanGDP, 2 μM; and ΔIBB importin α1, 1 μM. Bar = 20 μm.