FIG. 3.

Density gradient and ultrastructural analysis of COS-1 cells that expressed poliovirus 3A protein. (A) Cytoplasmic membranes from cells expressing 3A protein were separated on a 12% stock isotonic Percoll; proteins in each fraction were detected by immunoblotting using antibodies directed against the poliovirus 3A protein, calnexin (ER), and mtHSP70 [HSP70m(mito); mitochondria]; lightest fractions are at the left. The distribution profiles of Golgi and lysosomal proteins did not vary significantly from the patterns displayed in Fig. 2 and were not included for simplicity. (B) Ultrastructure of COS-1 cell expressing poliovirus 3A protein. N, nucleus. Bar = 1 μm.