FIG. 4.

Cell-free nuclear import assays. (A) Uninfected cells (mock infected) or cells that had been infected with poliovirus for the indicated amount of time were permeabilized and used in an in vitro nuclear import assay. Assays were carried out in the presence of rabbit reticulocyte lysate (RRL) as a source of cytosolic factors. The top panels show GFP using an FITC filter, and the bottom panels show Hoechst staining of DNA using a UV filter. (B) Same as in panel A except rabbit reticulocyte lysate was omitted from the reactions. (C) Same as in panel A except that after virus adsorption the cells were incubated in the presence of 2 mM GuHCl. Mock-infected cells were exposed to GuHCl for 4 h. All GFP images were acquired by using identical exposure times and digital manipulations.